Fact-checked by Grok 2 weeks ago

Energy modeling

Energy modeling is the process of developing and applying computational simulations to represent energy systems, enabling predictions of production, consumption, distribution, and optimization across scales from individual buildings to national grids and global economies. These models integrate physical laws, empirical data on fuels and technologies, and economic factors to evaluate scenarios such as efficiency improvements, renewable integration, and policy impacts. Originating in the 1970s amid oil crises, energy modeling has advanced through tools like the U.S. National Energy Modeling System (NEMS), which simulates U.S. energy markets, and EnergyPlus, a whole-building simulation engine that has informed standards for low-energy design since its 2001 release. Key applications include supporting building codes for reduced consumption, forecasting grid reliability under variable renewables, and assessing decarbonization pathways, though achievements are tempered by persistent challenges in validation against real-world data. Controversies arise from documented inaccuracies, particularly in long-term projections where models often overestimate efficiency gains or underestimate intermittency risks in renewable-heavy scenarios, leading to critiques of overreliance for policy without robust sensitivity testing. Despite these limitations, ongoing refinements in data integration and hybrid approaches continue to enhance causal fidelity in simulating energy transitions.

Fundamentals

Definition and purpose

Energy modeling refers to the development and use of mathematical, statistical, and computational frameworks to represent and simulate the dynamics of energy systems, encompassing production, transformation, distribution, and consumption across scales from individual facilities to national or global economies. These models typically integrate physical principles—such as and —with economic variables like prices and demand elasticities, as well as technological parameters including rates and capacity factors. For example, the U.S. Energy Information Administration's National Energy Modeling System (NEMS), operational since 1993, employs modular components to project U.S. energy through 2050, linking sectors like and via calculations. The core purpose of energy modeling is to forecast potential outcomes under specified scenarios, enabling the evaluation of policy options, technological deployments, and market evolutions to enhance , efficiency, and environmental performance. Models support tasks such as estimating the impacts of carbon pricing on fuel switching—NEMS, for instance, simulated a 20-30% reduction in use by 2040 under certain regulatory assumptions—or optimizing building designs to cut use by up to 50% through iterative simulations of HVAC and envelope systems. By quantifying causal linkages, such as how renewable integration affects grid reliability amid variable weather inputs, these tools inform regulatory standards, investment decisions, and research priorities, though their reliability hinges on accurate parameterization of uncertainties like future fuel costs. In broader applications, energy models assess systemic risks and transitions, including the feasibility of achieving by mid-century through pathways involving and deployment, as explored in integrated assessments that balance supply constraints with demand growth rates averaging 1-2% annually in developed economies. This analytical capability extends to stress-testing resilience against events like supply disruptions, where simulations reveal that diversified portfolios—e.g., combining at 25% capacity factors with baseload —can stabilize costs within 10-15% variance compared to fossil-heavy baselines. Ultimately, the utility of energy modeling lies in its capacity to distill complex interactions into actionable insights, provided inputs reflect empirical data rather than unsubstantiated assumptions.

Historical origins and evolution

The practice of energy modeling traces its origins to the mid-20th century, with initial applications of techniques emerging in the to optimize energy supply chains and in growing industrial economies. These early models focused on simplifying complex systems through mathematical formulations that balanced costs against technical constraints, often applied by utilities and governments for short-term planning amid rising dependence. By the late , econometric approaches began incorporating macroeconomic variables to forecast demand, laying groundwork for more integrated frameworks, though limited by computational constraints and data availability. The marked a pivotal acceleration, exposing vulnerabilities in global markets and prompting governments to invest in long-range forecasting tools for policy analysis and crisis mitigation. This led to the establishment of the Energy Modeling Forum (EMF) in 1976 at , which convened modelers, policymakers, and industry experts to compare projections, identify methodological gaps, and enhance reliability through structured comparisons—such as reconciling divergent U.S. demand forecasts that had varied by factors of two or more. Concurrently, the initiated development of the MARKAL model in the late , a dynamic framework representing national systems over multi-decade horizons to minimize costs while tracking technology evolution and fuel substitutions. Subsequent evolution in the 1980s and saw a proliferation of bottom-up models emphasizing technology-specific details, contrasting with top-down macroeconomic simulations, enabling finer-grained analysis of efficiency improvements and fuel switching. Tools like the Long-range Energy Alternatives Planning (LEAP) system, first developed in 1980 for fuelwood assessment in , expanded into integrated platforms for scenario-building across developing and developed contexts. By the 2000s, models incorporated environmental externalities, such as greenhouse gas constraints under frameworks like the , evolving toward hybrid optimization-simulation hybrids to handle variable renewables and sector interdependencies; for instance, MARKAL's successor, TIMES, introduced in 2008, enhanced partial equilibrium representations with endogenous technological learning. Recent decades have emphasized open-source architectures and computational advances to address uncertainties in decarbonization pathways, though persistent challenges include reconciling model assumptions with empirical outcomes, as evidenced by EMF studies revealing systematic overestimation of energy intensities in prior decades.

Methodological Foundations

Bottom-up versus top-down approaches

Bottom-up approaches in energy modeling construct projections by aggregating detailed representations of individual technologies, end-uses, and processes within the , such as specific , , or power generation units. These models emphasize engineering data and physical constraints, enabling granular analysis of efficiency improvements, fuel switching, and deployment costs for discrete components before scaling to sectoral or national levels. For instance, bottom-up models might simulate hourly from building-level simulations using tools like TRNSYS, which accounts for and specifications. In contrast, top-down approaches begin with macroeconomic aggregates, such as GDP, labor supply, and historical consumption patterns, treating energy as one input within broader economic equilibria often modeled via econometric or frameworks. These models prioritize behavioral responses, including price elasticities for between energy sources or effects where gains lead to increased consumption, derived from observed data rather than engineered parameters. Top-down methods thus capture economy-wide feedbacks, such as how affects investment and trade, but at the expense of technological specificity. The primary distinction lies in scope and granularity: bottom-up models excel in evaluating technology-driven scenarios, such as the potential for variable renewable integration by modeling dispatchable versus intermittent sources at sub-hourly resolutions, but often neglect macroeconomic interactions like or capital constraints. Top-down models, conversely, integrate energy decisions into general economic optimization, revealing causal links like how carbon taxes alter sectoral outputs, yet they aggregate technologies into averaged coefficients that may undervalue disruptive innovations. This aggregation can lead to underestimation of long-term potentials, as evidenced by discrepancies in projected energy intensities where bottom-up estimates exceed top-down by factors of 1.5 to 2 in some sectoral analyses. Critics note that bottom-up models risk over-optimism by assuming cost-independent adoption of technologies without accounting for barriers or behavioral inertia, while top-down models may embed historical biases from , potentially understating feasible transitions in rapidly evolving sectors like . methods, combining disaggregated details with macroeconomic feedbacks, address these limitations but introduce coordination challenges in . Empirical validations, such as those comparing model outputs to actual U.S. residential use from 1990–2015, show bottom-up approaches better matching end-use trends but diverging on due to omitted rebound effects estimated at 10–30% of savings.

Optimization, simulation, and hybrid techniques

Optimization techniques in energy modeling involve mathematical programming to identify cost-minimal or emission-minimal configurations of energy systems subject to technical, economic, and policy constraints. () and mixed-integer linear programming (MILP) dominate, as they efficiently handle large-scale problems like capacity expansion and dispatch in and integrated energy systems; for instance, MILP models discrete decisions such as building new plants versus existing ones. variants incorporate in fuel prices or demand via scenario-based or , improving realism over deterministic approaches but increasing computational demands. These methods assume perfect foresight in long-term planning, which can overestimate efficiency in volatile markets unless hybridized with behavioral elements. Simulation techniques replicate dynamic energy system behaviors over time, capturing nonlinearities and stochastic processes that optimization often abstracts. (DES) models sequential operations like power plant startups, while agent-based modeling (ABM) simulates interactions among heterogeneous actors such as consumers or firms responding to price signals. (SD) emphasizes feedback loops, such as reinforcement from falling renewable costs driving adoption. These approaches excel in forecasting short-term variability, like hourly load profiles, but require extensive parameterization and validation against empirical data to avoid . Monte Carlo methods propagate input uncertainties through simulations to generate probabilistic outputs, essential for in renewable-heavy grids. Hybrid techniques integrate optimization's prescriptive power with simulation's descriptive fidelity, addressing limitations like optimization's rigidity to real-world dependencies. Simulation-optimization hybrids iteratively refine decisions: simulations generate scenarios for optimization , while optimizers select policies evaluated via forward simulations. In hybrid renewable energy systems (HRES), tools like employ genetic algorithms within simulation frameworks to size components such as panels and batteries, minimizing levelized costs under variable weather. discrete-continuous models, often based on formalism, link production processes to energy flows, enabling granular analysis of efficiency trade-offs in industrial settings. Such methods enhance causal accuracy by embedding empirical dynamics, though they demand high computational resources and careful calibration to prevent bias from over-reliance on historical data.

Core inputs, assumptions, and uncertainties

Energy models rely on a range of core inputs to represent physical, economic, and technological realities. Primary inputs include historical and projected energy demand by sector (e.g., residential, industrial, transportation), derived from econometric data on GDP growth, population demographics, and end-use efficiencies; for instance, the (EIA) uses disaggregated sectoral data from surveys like the Residential Energy Consumption Survey (RECS) to baseline demand. Supply-side inputs encompass resource endowments such as proven reserves of fossil fuels, renewable potential (e.g., solar irradiance maps or wind speed distributions), and infrastructure capacities like grid transmission limits. Technology-specific parameters include capital costs, operation and maintenance expenses, conversion efficiencies, and lifetimes; the National Renewable Energy Laboratory (NREL) Annual Technology Baseline provides detailed cost trajectories for technologies like , which fell from $4.00/W in 2010 to $0.30/W in 2023 due to scaling effects. Fuel prices form another critical input, often drawn from futures markets or historical series, with natural gas prices in the U.S. benchmark averaging $2.50/MMBtu in 2023 but exhibiting high volatility. Assumptions underpin model dynamics and often introduce normative elements. Common assumptions include for fuels (typically 0.1-0.5 in partial equilibrium models), learning curves for technology cost declines (e.g., 20% cost reduction per doubling of cumulative capacity for wind turbines), and discount rates (3-7% for calculations, reflecting debates). Behavioral assumptions, such as effects where efficiency gains lead to increased consumption (estimated at 10-30% in empirical studies), are frequently parameterized conservatively despite evidence from meta-analyses showing higher magnitudes in developing economies. Policy assumptions, like carbon pricing paths or subsidy phase-outs, are scenario-dependent; for example, the (IEA) Stated Policies Scenario assumes partial implementation of commitments, leading to 2.4°C warming by 2100, whereas the Scenario enforces stricter net-zero pathways. These choices reflect modelers' priors, with bottom-up models often overemphasizing engineering feasibility over macroeconomic feedbacks, as critiqued in peer-reviewed comparisons showing top-down models better capturing income effects. Uncertainties arise from inherent variability and incomplete knowledge, necessitating sensitivity analyses and probabilistic methods like simulations. Key sources include technological innovation rates (e.g., battery storage costs projected to drop 50-70% by 2030 but with wide error bands due to disruptions), geopolitical risks affecting import-dependent fuels (e.g., supply shocks modeled with processes in EIA's Annual Energy Outlook), and feedbacks altering renewable yields (e.g., variability under IPCC RCP scenarios). Demand-side uncertainties stem from trends and lifestyle changes, with studies indicating 20-50% variance in sector projections based on EV adoption rates. Academic critiques highlight systemic underestimation of tail risks in deterministic models, such as events, advocating for ensemble approaches across multiple models to quantify structural uncertainties; for instance, the (SSPs) framework spans narratives from sustainability (SSP1) to fossil-fueled development (SSP5), revealing output divergences up to 30% in cumulative emissions. Source credibility varies, with government models like NEMS prone to policy optimism biases, whereas independent efforts like those from the Joint Program incorporate more robust error propagation.

Model Categories

End-use and building-level models

End-use energy models disaggregate total sectoral energy demand into specific consumption categories, such as space heating, cooling, lighting, appliances, and water heating, primarily in residential, commercial, and industrial contexts. These models rely on bottom-up methodologies that integrate engineering data on equipment stock, efficiencies, and operational patterns with statistical representations of user behavior and socioeconomic drivers. For instance, the U.S. Energy Information Administration (EIA) employs regression-based engineering models in the Commercial Buildings Energy Consumption Survey (CBECS) to estimate end-use consumption, using building characteristics like floor area, vintage, and equipment type as inputs to predict fuel-specific demands. Similarly, probabilistic simulations account for variability in appliance usage over time, drawing from activity-based data to generate time-series profiles of energy draw. Building-level models extend end-use analysis by simulating the dynamic interactions within individual structures, incorporating physics-based representations of thermal dynamics, ventilation, and equipment performance. These tools model through building envelopes, internal gains from occupants and lighting, and system responses to weather and schedules, often at sub-hourly resolutions. The U.S. Department of Energy's EnergyPlus software, for example, solves coupled differential equations for zone air temperatures, surface heat balances, and HVAC operations, enabling predictions of annual energy use and peak loads with inputs including geometry, materials, and control strategies. Prototype models, such as those developed for Standard 90.1 compliance, represent standardized archetypes across 16 commercial building types and 19 climate zones, facilitating code development and retrofit assessments by scaling simulations to stock-level aggregates. Key challenges in these models include handling uncertainties from occupancy patterns, equipment degradation, and weather variability, often addressed through methods or sensitivity analyses. The National Renewable Energy Laboratory's (NREL) End-Use Load Profiles dataset, derived from thousands of simulated buildings, provides 15-minute resolution data separated by end-use, revealing, for instance, that lighting and space conditioning dominate commercial loads in certain archetypes. Validation against empirical data, such as metered consumption, underscores discrepancies; for example, models may overestimate appliance loads by 10-20% without calibrated behavioral inputs, highlighting the need for hybrid approaches combining simulation with measured data. These models support applications like demand-side management and efficiency policy evaluation but require cautious interpretation due to assumptions about technology adoption rates, which can vary significantly by region and economic conditions.

Electricity sector models

Electricity sector models simulate the generation, transmission, distribution, and consumption of to support planning, operations, and . These models typically operate at regional, , or interconnected scales, incorporating factors such as demand profiles, generator characteristics, fuel prices, and regulatory constraints to forecast system evolution and performance. Capacity expansion models project long-term investments in power plants, renewables, , and transmission lines, often spanning 20-40 years, by optimizing cost-minimizing portfolios that meet reliability standards like reserve margins. Production cost models, by contrast, evaluate short- to medium-term dispatch decisions, simulating hourly or sub-hourly generator commitments and outputs to minimize operational expenses while balancing supply with variable loads and intermittent sources like and . Network reliability models integrate power flow analyses to assess transmission constraints, voltage , and contingency risks, ensuring simulated configurations avoid blackouts under stressed conditions. Core techniques in these models emphasize optimization and simulation. Linear and mixed-integer linear programming (MILP) dominate capacity expansion and dispatch formulations, solving for least-cost solutions under constraints like energy balances and capacity limits; for instance, MILP handles binary decisions for unit on/off states in unit commitment problems. Stochastic variants incorporate uncertainties in renewables output or demand via scenario trees or Monte Carlo methods, reflecting real-world variability where wind generation capacity factors average 35-45% in the U.S. compared to 80-90% for nuclear. Simulation approaches, often chronological or sequential, replicate time-series operations to capture temporal dynamics, such as diurnal load peaks or seasonal hydro inflows, enabling assessments of metrics like levelized cost of electricity (LCOE) or curtailment rates. Hybrid methods combine these, linking expansion outputs to detailed dispatch runs for iterative refinement, as in models evaluating decarbonization pathways where storage deployment rises to mitigate over 20% renewable penetration without excessive firm capacity needs. Inputs include granular data on technologies—e.g., overnight capital costs ($1,000-2,000/kW for gas combined cycle, $3,000-4,000/kW for utility-scale solar as of 2023)—fuel trajectories, load growth (projected 1-2% annually in mature economies), and policies like emissions caps. Outputs yield capacity mixes, generation profiles, system costs (e.g., total annualized costs in billions), emissions trajectories, and reliability indicators like loss-of-load probabilities below 1 event per decade. Uncertainties arise from parameter sensitivity; for example, a 20% error in solar cost decline assumptions can shift optimal renewable shares by 10-15 percentage points in expansion models. Validation against historical data, such as matching observed 2022 U.S. renewable growth to 12% of generation, underscores model fidelity, though limitations persist in capturing rare events or market behaviors like strategic bidding. Government and research institutions, including the U.S. Department of Energy and NREL, develop these tools, but outputs warrant scrutiny for assumptions favoring subsidized technologies, as empirical over-optimism in battery cost reductions has led to revised projections in recent analyses.

Integrated energy system models

Integrated energy system models simulate the interactions among multiple energy sectors, such as , networks, , and transportation, to assess holistic including supply-demand balances, conversion processes, and cross-sectoral dependencies. These models differ from sector-specific approaches by explicitly accounting for couplings like conversion or electrified heating, which can alter peak loads and resource utilization across infrastructures. For instance, increased renewable penetration may necessitate flexible gas plant operations or to maintain stability. Methodologically, integrated models often combine optimization frameworks, such as , with techniques to minimize objectives like total system cost or emissions while enforcing constraints on capacities, limits, and energy balances. typically spans hourly to annual scales, with finer granularity for capturing diurnal variability in renewables or demand. Uncertainty handling is integral, employing methods including simulations for probabilistic scenarios or to address input variability in fuel prices, technology costs, or weather-dependent generation. Data inputs encompass technology performance parameters, network topologies, and socioeconomic drivers, often sourced from empirical measurements or engineering databases. A key advantage lies in revealing synergies and trade-offs overlooked in isolated analyses, such as cost savings from coordinated dispatch of combined heat and power units that serve both and thermal needs. However, their complexity demands high computational resources; for example, multi-period optimizations over national-scale systems can require on high-performance clusters. Validation typically involves calibration against historical data, like matching observed energy flows during the 2021 grid event where interdependencies exacerbated shortages. In practice, these models support evaluations of decarbonization pathways, projecting that sector integration could reduce abatement costs by 20-30% through efficient resource sharing, though results vary with assumptions on technology adoption rates. Limitations include potential over-reliance on linear approximations, which may underestimate nonlinear dynamics like storage degradation or market feedbacks.

Macroeconomic and energy-economy models

Macroeconomic and energy-economy models represent top-down approaches in energy modeling, aggregating economic sectors to analyze interactions between energy systems and broader macroeconomic variables such as (GDP), , , and balances. These models emphasize behavioral responses to shocks, including effects, income feedbacks, and general equilibrium adjustments, often calibrated to historical data or matrices rather than detailed representations. They are particularly suited for evaluating the economy-wide implications of energy policies, such as carbon pricing or subsidies, by simulating how changes in energy prices ripple through production functions and consumer utility maximization. A prominent subclass consists of (CGE) models, which solve for simultaneous across goods, labor, and capital under assumptions of rational agents and or imperfect market structures. For instance, the GEM-E3 model, developed by the of the , is a multi-regional, multi-sectoral CGE framework that incorporates substitution possibilities and assesses policies like the EU Emissions Trading System, projecting GDP impacts from decarbonization scenarios with elasticities drawn from econometric estimates. Similarly, the GTAP-E extension of the Global Trade Analysis Project database applies CGE methods to trade and policy, revealing that a global could reduce world GDP by 0.5-1% by 2030 under baseline assumptions, though results vary with Armington trade elasticities typically ranging from 4-8 for commodities. Econometric and dynamic stochastic general equilibrium variants extend these by incorporating time-series data for forecasting. The E3ME model, a global sectoral econometric system, links energy demand to macroeconomic drivers via cointegrated equations estimated from post-1970 data, enabling simulations of long-term transitions; for example, it estimates that aggressive EU renewable targets could boost GDP by 0.2% annually through induced innovation but raise energy costs by 10-15% without compensatory measures. In the United States, the Macroeconomic Activity Module within the Energy Information Administration's National Energy Modeling System (NEMS) uses IHS Markit's U.S. economy model to generate over 1,700 variables, projecting that oil price shocks above $100 per barrel in 2023 terms could contract GDP by 0.3-0.5% via reduced industrial output and consumer spending. Hybrid linkages address limitations of pure top-down models, such as underrepresentation of , by iteratively coupling with bottom-up models. Procedures like those in MESSAGE-MACRO combine partial equilibrium energy optimization with macroeconomic closure rules, ensuring consistency in prices and quantities; applications show that ignoring macroeconomic feedbacks can overestimate mitigation costs by 20-50% in scenarios targeting by 2050. Uncertainties arise from parameter sensitivity—e.g., labor supply elasticities of 0.5-1.0 can swing GDP impacts of energy taxes by factors of two—and reliance on historical correlations that may not hold amid structural shifts like digitalization or geopolitical disruptions. Empirical validation against post-2008 data indicates these models generally capture short-term contractions well but diverge in long-run growth projections due to varying treatments of .

Key Established Models

LEAP and scenario-based planning tools

The Long-range Energy Alternatives Planning (LEAP) system, developed by the Stockholm Environment Institute, is a scenario-based software tool designed for analysis, assessment, and integrated energy-environment modeling. LEAP structures analyses around user-defined s that account for energy demand across sectors such as residential, , , and ; energy transformation processes like and refining; and primary resource supply including fossil fuels, renewables, and imports. Unlike optimization-focused models, LEAP emphasizes flexible, narrative-driven scenario construction, allowing planners to explore "what-if" pathways by specifying assumptions on technology adoption, efficiency improvements, fuel switching, and policy interventions without enforcing a single objective like cost minimization. LEAP's core methodology relies on bottom-up frameworks, where energy balances are built from detailed activity data, end-use efficiencies, and factors, enabling comprehensive tracking of gases, air pollutants, and resource extraction across an . On the demand side, it models final using exogenous drivers like , GDP, and behavioral parameters; supply-side modeling includes of capacity expansion, dispatch, and costs via , , or limited optimization routines. The tool incorporates uncertainty through sensitivity analyses, simulations, and branching, facilitating robust exploration of risks such as price or technological breakthroughs. Recent enhancements, introduced in 2024, include cloud-based databases for collaborative data sharing, energy affordability metrics integrating household expenditure modeling, and a for custom extensions like AI-assisted generation. Scenario-based planning tools like LEAP prioritize exploratory foresight over prescriptive outcomes, supporting long-term horizons typically spanning 20–50 years with annual or finer time-steps. They enable comparative evaluation of baselines against intervention scenarios, such as those aligned with Nationally Determined Contributions under the , by quantifying metrics like demand, cumulative emissions, and investment needs. LEAP has been applied in over 100 countries for national energy master plans, with documented uses in for detailed sectoral modeling of and fuel demands alongside supply options. Its user-friendly interface, requiring minimal programming expertise, contrasts with more computationally intensive alternatives, though this accessibility can introduce subjectivity in assumption selection, necessitating validation against historical data for credibility. Extensions like LEAP-IBC integrate co-benefits analysis, such as health impacts from reduced , to inform holistic policy trade-offs.

MARKAL/TIMES and linear programming frameworks

MARKAL, or Market Allocation model, is a bottom-up, dynamic framework developed in the late under the International Energy Agency's Implementing Agreement on Energy Technology Systems Analysis Programme (ETSAP) to analyze national or regional s over multi-decade horizons, typically 40 to 50 years. The model represents the through a Reference Energy System (RES), a network diagram linking primary resources, conversion technologies, and end-use demands, formulated as a that minimizes the present-value cost of meeting exogenous energy service demands subject to technical, resource, and policy constraints such as emissions limits. In this setup, decision variables include capacities installed, activity levels of technologies, and flows of energy commodities across periods, solved via standard LP solvers to yield optimal technology mixes, investment paths, and fuel substitutions under assumptions of and foresight within discrete time steps. The core of MARKAL treats technologies as processes with fixed input-output coefficients, linear cost functions (, operating, fuel), and bounds on availability, enabling tractable optimization but approximating non-linearities like learning curves or through piecewise linear functions or exogenous adjustments. Multi-objective extensions allow trade-offs, such as cost versus emissions, by incorporating lexicographic optimization or weighted objectives, while the dynamic structure links periods through carryover and discounted costs. Early implementations, such as those for the U.S. Department of in the , demonstrated its use in evaluating oil import reduction strategies by simulating shifts to and technologies under varying fuel prices and efficiency improvements. TIMES, or The Integrated MARKAL-EFOM System, evolved from MARKAL in the early as a more flexible successor, integrating elements of the EFOM (Energy Flow Optimization Model) to enhance intertemporal linkages and handle variable demands, , and seasonal dynamics through a continuous-time approximation within . Implemented in the GAMS , TIMES generates region-specific instances by compiling user-defined databases into LP matrices, optimizing least-cost system configurations across user-specified constraints like CO2 budgets or renewable mandates, with variables for process activities, trade, and emissions tracking. Unlike MARKAL's step-wise , TIMES employs dynamic optimization over a full horizon, capturing capital and via endogenous or exogenous parameters, though it retains LP's by discretizing time into representative periods and load curves. Both frameworks emphasize technology-rich detail, with TIMES extending MARKAL's static representation to include flexible forms like cumulative availability curves for resources and multi-regional linkages in global variants such as ETSAP-TIAM, enabling of trade and spillover effects. ensures computational efficiency for large-scale systems—models with thousands of technologies solve in minutes using solvers like CPLEX—but requires calibration to historical data for realism, as uncalibrated instances may overestimate substitution elasticities due to idealized . Applications include ETSAP's national models for the and , where TIMES variants projected cost-optimal paths to 2050 under carbon pricing, revealing reliance on co-firing and for baseload power.

NEMS and national forecasting systems

The National Energy Modeling System (NEMS) is a computer-based, modular simulation model developed and maintained by the (EIA) to project U.S. energy production, consumption, prices, and environmental emissions through 2050. It integrates supply, conversion, and demand sectors with macroeconomic feedbacks, iterating modules sequentially until market equilibrium is achieved between energy supplies and demands. NEMS supports the EIA's Annual Energy Outlook (AEO), providing baseline and policy scenario forecasts that inform federal legislation, such as the Energy Policy Act of 1992, under which it was initially mandated. NEMS comprises nine core modules: the Macroeconomic Activity Module (MAM) for GDP and employment projections; Residential Demand Module (RDM), Commercial Demand Module (CDM), Industrial Demand Module (IDM), and Transportation Demand Module for sector-specific consumption; Coal Market Module (CMM), Liquid Fuels Market Module (LFMM), and Transmission and Distribution Module (NGTDM) for supply-side dynamics; and Module (EMM) for power generation and capacity expansion. These interact via an Integrating Module that handles data flows, ensuring consistency in prices, quantities, and emissions across fuels like coal, oil, , renewables, and nuclear. Unlike optimization models, NEMS employs behavioral based on econometric equations calibrated to historical data, incorporating assumptions on , fuel switching, and regulatory constraints. For national forecasting, NEMS serves as the benchmark U.S. system, generating disaggregated projections by region, fuel, and end-use to evaluate policies like carbon pricing or renewable standards. Internationally, analogous systems include Canada's National Board models for integrated supply-demand simulations and the European Commission's PRIMES model for EU-wide energy-economy projections, though these often incorporate greater optimization elements than NEMS's simulation approach. NEMS outputs have historically informed U.S. of analyses, with updates reflecting events like the boom, which revised price forecasts downward by over 50% in AEO iterations from 2008 to 2012. Its modular design allows scenario testing, such as the AEO2025's reference case assuming no new policies beyond those enacted by mid-2024.

Open-source alternatives like OSeMOSYS

OSeMOSYS, the energy MOdelling SYStem, is a free, open-source framework designed for long-term integrated assessment and planning, generating optimization models for energy systems at local, national, or multi-regional scales. Initially developed with working code released in , it employs to minimize costs while meeting specified energy demands and constraints, such as resource availability and emissions limits. The system's core formulation spans fewer than five pages of documented code, emphasizing simplicity and transparency to facilitate teaching, customization, and extension by users without proprietary restrictions. Key features include modeling of energy supply chains from primary resources to end-use demands, incorporation of storage technologies via linear approximations, and support for scenario analysis on capacity expansion, fuel mixes, and environmental impacts. It requires minimal input data—typically time-sliced demands, technology costs, and efficiencies—reducing setup time compared to more data-intensive proprietary tools like TIMES or MARKAL. Interfaces such as MoManI and clicSAND enhance usability by providing graphical tools for data input, optimization via solvers like GLPK, and result visualization, eliminating the need for command-line interaction in some implementations. OSeMOSYS has been applied in over hundreds of studies, including contributions to IPCC assessments, UN and policy papers, and official national energy strategies, such as for and global electricity systems. Its open-source nature enables rapid adaptation for specific contexts, like low-data environments in developing regions, and integration with tools like LEAP for hybrid scenario-based and optimization approaches. Advantages of OSeMOSYS over closed-source alternatives include zero licensing costs, full code accessibility for auditing and modification, and community-driven improvements, which mitigate risks of vendor lock-in and opaque assumptions prevalent in commercial models. This transparency supports independent verification and reduces potential biases from proprietary data calibrations, though users must still validate inputs empirically. Other open-source alternatives, such as oemof, Calliope, and GENeSYS-MOD, offer similar linear or mixed-integer optimization capabilities but differ in flexibility for multi-energy carriers or temporal resolution; for instance, oemof emphasizes Python-based modularity for hybrid renewable systems. These tools collectively democratize access to rigorous energy modeling, enabling broader scrutiny and innovation in policy and investment decisions.

Practical Applications

Policy development and regulatory forecasting

Energy models facilitate policy development by enabling the simulation of regulatory scenarios, allowing analysts to quantify potential economic, environmental, and supply-chain impacts of interventions such as emissions caps, subsidies for low-carbon technologies, or standards. These simulations typically incorporate variables like technology costs, fuel prices, and demand growth to generate projections of energy supply, demand, and prices over multi-decade horizons. For example, bottom-up models optimize system configurations under policy constraints to identify least-cost pathways compliant with regulatory goals, informing decisions on carbon taxes or renewable mandates. In the United States, the National Energy Modeling System (NEMS), maintained by the (EIA), serves as a primary tool for regulatory . NEMS integrates modules for supply, conversion, and end-use sectors to produce the Annual Energy Outlook (AEO), which forecasts U.S. markets through 2050 under reference cases and policy alternatives, such as those evaluating the effects of the Clean Air Act or provisions. These outputs support regulatory impact analyses by estimating compliance costs, emissions reductions, and market disruptions; for instance, NEMS projected that stricter vehicle efficiency standards could reduce transportation sector oil demand by 1-2 million barrels per day by 2030 in certain scenarios. Policymakers, including and agencies like the Environmental Protection Agency, rely on AEO data for drafting legislation and rules, though the model's equilibrium-based approach assumes market responsiveness that may not fully capture regulatory enforcement challenges. Internationally, partial-equilibrium models like the TIMES framework, developed under the IEA-ETSAP program, are applied in regulatory forecasting for scenario-based planning. TIMES employs to minimize system costs subject to policy-driven constraints, such as binding limits or phase-outs of fossil fuels. The European Commission's JRC-EU-TIMES model, for example, has been used to assess EU regulatory packages like the initiative, projecting that achieving 55% emissions reductions by 2030 would require €2.5-3 trillion in cumulative investments through 2050, with shifts toward and in and sectors. National implementations, such as Finland's TIMES-VTT, evaluate domestic regulations by linking energy scenarios to , aiding forecasts of under varying assumptions. Despite their utility, energy models in policy contexts can exhibit directional biases stemming from input assumptions, such as optimistic learning rates for intermittent renewables or understated integration costs, potentially favoring regulatory paths aligned with institutional priorities over empirically robust alternatives. Studies indicate that in low- and middle-income countries, model-driven policies sometimes overlook local data gaps, leading to forecasts that undervalue needs. To mitigate this, best practices emphasize sensitivity analyses and ensemble modeling, where multiple frameworks like NEMS and TIMES are compared to bound uncertainties in regulatory projections.

Investment and resource allocation

Energy models are employed to guide investment decisions by optimizing the selection and timing of capital expenditures across energy technologies, balancing costs against projected demands, reliability requirements, and policy constraints such as carbon limits. Linear programming frameworks like TIMES evaluate trade-offs in deploying generation capacity, storage, and grid upgrades to achieve least-cost pathways, incorporating discount rates and technology learning curves to prioritize high-return investments. In practice, these models inform in utility integrated resource plans (IRPs), where simulations determine the mix of supply-side additions like , , and alongside demand-side measures. For instance, the NREL Resource Planning Model (RPM), a capacity expansion tool for systems, has been used to assess scenarios for utility territories, states, or balancing authorities, outputting optimal capacity builds that minimize production costs subject to reserve margins and limits. U.S. utilities, required to file IRPs in over 20 states as of , rely on such modeling to allocate billions in investments; for example, recent IRPs project shifts toward greater shares of variable renewables and batteries to meet growing demands while hedging against price volatility. At the national level, TIMES implementations support strategic resource distribution in energy strategies, as seen in Denmark's TIMES-DK model, which optimizes investments across sectors including , , and to minimize costs under decarbonization targets through 2050. These applications extend to international contexts via IEA-ETSAP collaborations, where TIMES-derived analyses allocate resources toward technology clusters like renewables or based on empirical cost data and . However, outcomes depend heavily on input parameters such as levelized costs, which models update periodically; for example, declining prices from $1,000/kWh in 2010 to under $150/kWh by 2023 have shifted allocations toward storage in recent runs.

Transition scenarios including decarbonization

Transition scenarios in energy modeling project pathways for shifting from fossil fuel-dominant systems to low-carbon alternatives, typically aiming for by mid-century to align with climate targets such as limiting warming to 1.5°C. These scenarios employ optimization frameworks like TIMES or MARKAL, which minimize system costs subject to constraints on carbon budgets, technology deployment, and demand growth, often incorporating variables for expansion, of end-uses, and (CCS). For instance, TIMES-based analyses for industrial sectors indicate that achieving deep decarbonization may require replacing 62% of inputs with low-carbon alternatives, alongside CCS contributing up to 33% of emission reductions in energy-intensive industries. Such models simulate hourly or annual balances of , factoring in storage, grid flexibility, and policy instruments like carbon pricing. Decarbonization pathways commonly emphasize rapid scaling of variable renewables like and , which in net-zero scenarios from integrated assessment models () supply 60-80% of by 2050, necessitating vast expansions in transmission infrastructure and battery storage to manage . Electrification extends to , heating, and , potentially reducing global energy demand by 8% relative to today despite , as projected in pathways assuming gains and behavioral shifts. and biofuels emerge as hard-to-abate sector solutions, though their modeled roles vary: in some TIMES implementations for , production reaches 10-20% of final energy by 2050 under stringent CO2 caps. Negative emissions technologies, including and bioenergy with (BECCS), feature prominently to offset residual emissions, with 177 analyzed net-zero scenarios relying on them for 5-15 GtCO2 removal annually by century's end. Modeling these transitions reveals causal challenges rooted in physical and economic realities, such as bottlenecks for critical minerals—lithium demand for batteries could surge 40-fold by 2040 in aggressive paths—and land use conflicts for or renewables. Grid stability poses another hurdle, as high renewable penetration (over 70%) demands overbuild factors of 2-3 times capacity to ensure reliability during low-output periods, increasing by 20-50% in some regional optimizations. Economic critiques highlight models' frequent underestimation of transition costs; for example, IEA's scenario assumes uninterrupted technology learning curves that historical data disputes, with real-world delays in deployment exceeding projections by factors of 10 in capacity additions since 2010. Source credibility varies, with IAMs and ESOMs like TIMES often critiqued for institutional biases toward optimistic decarbonization narratives, as they prioritize equilibrium outcomes over disruptive risks like geopolitical supply disruptions or policy reversals—evident in the Energy Modeling Forum's EMF-37 study, where U.S. net-zero paths across models assume uniform negative emissions scalability unproven at gigatonne levels. Sensitivity analyses in these scenarios underscore parameter uncertainty: a 20% variance in renewable cost declines alters pathway feasibility, shifting reliance from solar/wind to nuclear or fossil-CCUS hybrids. Empirical validation against past forecasts, such as overpredicted shale gas impacts on emissions, indicates systematic errors in behavioral and market responses, urging caution in treating model outputs as prescriptive rather than exploratory. Despite limitations, these scenarios inform policy by quantifying trade-offs, such as prioritizing dispatchable low-carbon sources like nuclear to minimize system costs in high-renewable mixes.

Evaluation and Reliability

Validation methods and empirical testing

Validation of models relies on empirical methods to assess their to real-world , including to historical datasets, hindcasting, and evaluations. involves adjusting model parameters to match observed , production, and prices from past periods, often using high-resolution datasets to minimize discrepancies between simulated and actual outcomes. Hindcasting, a key technique, simulates historical scenarios using only data available at the start of the period, enabling evaluation of whether the model can reproduce known events without ; for instance, bottom-up technology-rich models have demonstrated improved accuracy in hindcasting electricity demand trends when incorporating detailed sectoral data. Empirical testing extends to out-of-sample validation, where past model projections are compared against realized data to quantify errors in variables like fuel shares, emissions, and costs. In global models, hindcasting exercises have shown reasonable replication of long-term trends, such as shifts in fuel mixes, but often underestimate magnitudes due to unmodeled disruptions like rapid technological adoption. For frameworks like TIMES (successor to MARKAL), multi-model comparisons validate outputs by against alternatives, revealing alignments in cost-optimized pathways but divergences in diffusion rates. The U.S. Energy Information Administration's National Energy Modeling System (NEMS) undergoes annual empirical scrutiny by contrasting its Annual Energy Outlook projections with subsequent actuals, uncovering systematic biases such as overestimation of energy demand growth by up to 20% in certain scenarios from 1982 to 2006, attributable to unanticipated gains and shifts. Such tests highlight limitations in capturing exogenous shocks, prompting refinements like enhanced sensitivity to policy variables, though persistent errors underscore the challenge of modeling nonlinear causal interactions in energy s. Overall, these methods prioritize causal alignment over mere , with validation rigor varying by model type—partial models like NEMS excelling in aggregate trends but faltering on micro-level innovations.

Historical performance and forecasting discrepancies

Energy forecasting models have demonstrated mixed historical accuracy, with long-term projections often exhibiting systematic overestimations of energy demand and underestimations of supply-side innovations. Analyses of U.S. projections indicate average absolute percentage errors of about 4% for energy consumption forecasts spanning 10-13 years, reducing to roughly 2% for shorter horizons of 5-7 years, though these aggregates conceal larger deviations in specific sectors like natural gas, where errors exceeded 20% in some cases due to unanticipated technological shifts. The U.S. Energy Information Administration's (EIA) National Energy Modeling System (NEMS), used for Annual Energy Outlook (AEO) projections, has retrospectively shown persistent overestimation of natural gas prices—by factors of 2-3 times in pre-2010 forecasts—and underestimation of domestic production following the shale gas boom that accelerated after 2008, driven by hydraulic fracturing and horizontal drilling advancements not adequately captured in baseline assumptions. Internationally, the International Energy Agency's (IEA) World Energy Outlook (WEO) series reveals comparable discrepancies, with a review of 13 editions from 1995 to 2019 highlighting significant variations in projected primary energy demand and CO2 emissions across reference, current policies, and 450 ppm scenarios, often underestimating renewable energy deployment rates while overestimating fossil fuel shares in emerging economies. For instance, IEA and EIA projections for China's energy mix from 2004 to 2019 underestimated coal consumption growth in the 2000s and later renewable capacity additions, with mean absolute errors in total primary energy demand ranging from 5-15% depending on the scenario horizon. These patterns reflect model sensitivities to input assumptions, such as GDP growth trajectories, where errors in economic variables accounted for up to 70% of total forecast variance in decomposed analyses of historical cases. Broader evaluations of energy models, including frameworks like MARKAL/TIMES, underscore that discrepancies frequently stem from exogenous shocks—such as the 2008-2009 , which depressed demand 10-20% below pre-crisis projections—or breakthroughs like LED gains, which reduced electricity demand by 5-10% more than modeled in U.S. and forecasts from the early . Retrospective studies confirm that while aggregate energy supply-demand balances achieve reasonable accuracy over medium terms (errors <5% for 5-year horizons), fuel-specific forecasts suffer from status quo biases, favoring incumbent technologies and underweighting disruptive alternatives until post-hoc adjustments. Such historical shortfalls emphasize the challenges of incorporating nonlinear technological diffusion and policy feedbacks in equilibrium-based models, prompting ongoing refinements in validation protocols.

Sources of error and sensitivity analysis

Sources of error in energy system models primarily arise from parametric uncertainties, structural limitations, and scenario-dependent assumptions. Parametric uncertainties encompass variability in key inputs such as technology costs, fuel prices, demand forecasts, and resource availability; for example, solar irradiance data introduces substantial error in photovoltaic energy production estimates, often accounting for the largest share of annual yield uncertainty in such models. Structural errors stem from simplifications inherent to model architectures, particularly in linear programming frameworks like TIMES and MARKAL, which assume linear cost functions and perfect foresight but fail to represent nonlinear dynamics such as variable efficiency curves in power plants or economies of scale in deployment. These approximations can lead to over- or underestimation of system costs, especially under high renewable penetration where intermittency and forecasting errors amplify discrepancies between modeled and actual generation. Scenario uncertainties further compound errors through exogenous factors like policy changes or geopolitical events, which models often treat deterministically despite their inherent variability. Sensitivity analysis addresses these errors by quantifying how variations in inputs propagate to outputs, thereby assessing model robustness and identifying influential . In energy system optimization models (ESOMs), prevalent methods include simulations for probabilistic uncertainty propagation, stochastic programming to incorporate randomness in renewables or demands, and for worst-case scenarios. Local sensitivity approaches, such as one-at-a-time variations (e.g., altering technology costs by ±20% in TIMES implementations), reveal first-order effects but overlook interactions, potentially understating total uncertainty. Global , by contrast, explores the full input space simultaneously, providing variance-based indices (e.g., Sobol') to rank parameter importance; applications in long-term energy models have shown that rates and for technologies often dominate output variability in decarbonization pathways. Multi-model comparisons of sensitivity to energy technology costs, conducted across frameworks like those used in IPCC assessments, indicate that and carbon capture costs exhibit high leverage on total system emissions and investments, with changes in sign and magnitude highlighting structural differences between models. In practice, sensitivity results underscore the limitations of deterministic baselines; for instance, elastic demand formulations in MARKAL/TIMES reveal that underestimating price responsiveness can bias optimal technology mixes toward supply-side solutions over efficiency measures. Computational constraints often restrict comprehensive analyses, leading to selective parameter sweeps that may propagate unexamined assumptions, such as uniform learning rates across technologies. Advanced global methods mitigate this by prioritizing high-impact uncertainties, enhancing policy relevance; however, they demand significant data and processing resources, limiting adoption in real-time applications. Overall, while improves interpretability, persistent errors from unmodeled feedbacks—e.g., disruptions or behavioral responses—necessitate hybrid approaches combining optimization with agent-based or econometric validation.

Controversies and Critiques

Assumption-driven biases toward specific energy sources

Energy models, particularly integrated assessment models () used for long-term forecasting, incorporate parametric assumptions on technology costs, deployment rates, and system integration that systematically favor intermittent renewable sources like and over dispatchable alternatives such as or . These assumptions often project aggressive learning rates—typically 20-30% cost reductions per capacity doubling—for renewables based on short-term historical trends from 2010-2020, extrapolating them indefinitely despite evidence of and material constraints like rare earth supply limits. Such projections understate full-system costs, including the need for overbuild (2-3x capacity to achieve reliability) and backup generation, leading models to overestimate feasible penetration levels at 80% or more of electricity by 2050 in net-zero scenarios. Conversely, assumptions for embed biases from recent Western construction experiences, such as the Vogtle plant's costs escalating to $30 billion (from $14 billion initial estimate) and delays to 2023-2024 commissioning, inflating levelized costs to $80-150/MWh while downplaying successes in where standardized reactors achieve $3,000-5,000/kW overnight costs. frequently constrain nuclear deployment via arbitrary caps on annual build rates (e.g., 10-20 globally) or assume inflexible baseload operation, ignoring potential retrofits for load-following, which disadvantages it relative to variable renewables in high-renewable grids requiring firm capacity. This pessimism persists despite 's empirical capacity factors exceeding 90% versus 25-40% for unsubsidized and , and its near-zero marginal operational costs enabling economic dispatch priority. Fossil fuel assumptions in policy-driven models accelerate phase-out trajectories, projecting 80-100% reductions by 2050 under 1.5°C pathways, yet baseline scenarios often extend their role due to modeled reliability advantages in addressing renewable providing 10-20% of generation in systems for . Critics argue these decarbonization assumptions overlook causal realities like geographic variability in resource quality (e.g., declining at high latitudes) and the (EROI) penalties for renewables (10-20:1 versus 50-100:1 for dispatchables), biasing outcomes toward politically favored intermittent sources amid institutional incentives in academia and agencies like the IPCC that prioritize rapid green transitions over empirical validation of scale-up feasibility. Sensitivity analyses reveal that adjusting learning rates downward or incorporating granular hourly variability shifts optimal mixes toward 40-60% dispatchable capacity, underscoring how unstated priors distort policy recommendations.

Role in policy advocacy and economic impacts

Energy models frequently serve as quantitative tools in policy advocacy, enabling proponents to project scenarios that emphasize the urgency of decarbonization pathways, such as rapid scaling of intermittent renewables and , to influence legislative agendas like expansions or emissions targets. These projections often underpin arguments for interventions by assuming favorable technology cost declines and stringent carbon pricing, thereby supporting regulatory frameworks that prioritize environmental goals over immediate economic trade-offs. However, such modeling can exhibit , where assumptions align with preconceived policy preferences, potentially sidelining dispatchable sources like or that offer greater system reliability. Critics contend that this advocacy role amplifies institutional biases in model development, particularly from entities embedded in academic or international bureaucracies prone to underestimating barriers, leading to overstated feasibility of net-zero timelines. For example, integrated assessment models incorporating elevated social costs of carbon—often derived from uncertain damage functions—have been invoked to rationalize policies imposing compliance costs exceeding $50 per ton of CO2, influencing frameworks like the U.S. Reduction Act's $369 billion in clean energy incentives allocated through 2032. Economically, policies shaped by these models have induced reallocation effects, including subsidies totaling over $7 trillion globally for renewables and from 2010–2022, which distort signals, crowd out in unsubsidized alternatives, and elevate costs through intermittency premiums. In jurisdictions like the , model-driven advocacy for the Green Deal has correlated with electricity price surges averaging 200% from 2020–2023, straining industrial competitiveness and contributing to risks in energy-intensive sectors. While advocates cite long-term GDP gains from avoided , empirical assessments reveal short-term losses, with subsidy-induced fiscal burdens equating to 1–2% of GDP in aggressive transition scenarios, disproportionately affecting lower-income households via regressive energy price hikes. Furthermore, uniform cost-of-capital assumptions in many models bias against high-risk renewables by understating financing premiums, yet policy adoption amplifies these distortions through guarantees, resulting in stranded fossil assets valued at trillions and vulnerabilities exposed during events like the 2022 energy crisis. Overreliance on such projections has prompted economic modeling refinements to incorporate macroeconomic feedbacks, revealing that uncritical advocacy can exacerbate volatility rather than stabilize markets.

Debates over realism in technology and market projections

Energy models frequently face scrutiny for their assumptions regarding the pace and feasibility of technological advancements, with critics arguing that projections often extrapolate linear trends or optimistic learning curves without sufficient regard for historical precedents of slow diffusion. has highlighted the perils of long-range energy forecasting, noting repeated failures in predicting major shifts, such as the delayed commercialization of despite mid-20th-century hype, or the underestimation of the time required for in developing economies, which spanned decades rather than years. These errors stem from overlooking biophysical and infrastructural constraints, including the immense material and energy investments needed to scale technologies like batteries or hydrogen electrolyzers, leading Smil to deem rapid net-zero transitions by 2050 as having "low probability, if not impossibility." Conversely, some models have underestimated the exponential cost declines and adoption rates of renewables, particularly solar photovoltaics, where even optimistic forecasts from agencies like the IEA lagged behind actual deployment; for instance, global solar capacity additions in the 2010s exceeded projections by factors of several times due to unanticipated manufacturing scale-ups in . This discrepancy arises from models' conservative parameterization of learning rates or failure to incorporate aggressive policy-driven supply responses, though proponents caution that such past underestimations do not guarantee future scalability amid grid integration challenges and intermittency. Integrated assessment models (IAMs), such as , further exacerbate debates by simplifying innovation dynamics, often assuming exogenous technological progress without endogenizing path dependencies or R&D feedback loops, which can inflate projections for unproven solutions like . Market projections in energy models draw criticism for insufficient realism in capturing behavioral and economic feedbacks, such as price elasticity in demand or investor to volatile renewables. market models during clean energy transitions frequently abstract away inter-market linkages, like fuel switching or cross-border , resulting in distorted dispatch outcomes that overestimate renewables' dispatchable equivalence without storage breakthroughs. Critics from realist perspectives argue these omissions favor advocacy over causal mechanisms, as seen in IAMs' underrepresentation of bottlenecks for critical minerals—lithium demand for batteries, for example, could face shortages by the late under aggressive scenarios, per analyses of clean energy pathways. Empirical reveals that models incorporating granular simulations, rather than top-down aggregates, better align with observed discrepancies, such as slower-than-projected EV due to charging lags despite subsidies. These debates underscore a tension between aspirational scenarios and empirical validation, with sources like academic critiques often reflecting institutional incentives toward optimistic decarbonization narratives, while contrarian analyses prioritize historical data on rates. Resolution requires hybrid approaches blending bottom-up constraints with market elements, though persistent errors highlight the limits of deterministic projections in domains prone to technological surprises and geopolitical disruptions.

Recent Advances

Incorporation of AI and machine learning

Artificial intelligence (AI) and (ML) have been integrated into energy modeling to address limitations of traditional approaches, such as computational intensity and challenges in capturing non-linear dynamics in renewable integration and demand variability. ML techniques serve as surrogate models to approximate outputs from complex simulations, enabling faster scenario analysis in tools like EnergyPLAN, where neural networks reduce computation time from hours to seconds while maintaining accuracy within 5% for hourly energy balances in district-level systems. This approach, demonstrated in a 2024 study, facilitates rapid optimization of hybrid renewable systems under decarbonization constraints by training on historical simulation data to predict outcomes for new inputs like policy-driven carbon prices or technology costs. In integrated assessment models (IAMs) for decarbonization pathways, enhances granularity and predictive power by generating diverse scenarios from high-dimensional data, improving handling of uncertainties in technology adoption and supply chains compared to deterministic methods. For instance, generative models have been applied to refine IAM projections, enabling exploration of tail risks in net-zero transitions, such as variable renewable curtailment reduced by up to 20% through ML-optimized grid dispatch. The Energy Agency's 2025 analysis highlights 's role in forecasting variable renewable generation with error rates below 2% in real-time applications, outperforming physics-based models in regions with high and penetration. Recent advances post-2023 emphasize hybrid frameworks combining with domain-specific physics, as in for energy system dispatch, which achieves 10-15% efficiency gains in microgrids by learning optimal control policies from simulated environments incorporating geopolitical disruptions. Peer-reviewed reviews from 2024-2025 document 's expansion into fault detection and , reducing downtime in energy infrastructure by integrating time-series data from sensors with convolutional neural networks, though challenges persist in model interpretability and biases that can amplify errors in underrepresented scenarios. These integrations prioritize empirical validation against historical datasets, revealing 's superiority in short-term load (mean absolute percentage error under 3%) but cautioning against over-reliance without causal grounding to avoid spurious correlations in long-term decarbonization projections.

Enhanced handling of geopolitical and supply chain factors

Recent developments in energy modeling have incorporated explicit geopolitical risk indices to simulate disruptions from conflicts and sanctions, improving forecast resilience beyond static assumptions. A 2024 study integrated five geopolitical risk metrics—covering military tensions, diplomatic breakdowns, and trade conflicts—into electricity system optimization models for 31 European countries, allowing hindcasting of the 2022 Russia-Ukraine invasion's effects on gas prices and imports, which revealed model underestimations of supply shocks by up to 40% in baseline scenarios without such indices. This approach uses stochastic perturbations to energy import parameters, enabling probabilistic assessments of escalation risks, such as NATO-Russia confrontations or Middle East flare-ups, rather than treating geopolitics as exogenous noise. The International Energy Agency's World Energy Outlook 2024 updated its core modeling framework to emphasize geopolitical fragmentation, projecting that intensified U.S.- decoupling could raise clean energy technology costs by 20-30% through 2030 due to restricted critical mineral flows, with scenarios incorporating export bans on and . Similarly, the U.S. (NREL) enhanced its Annual Technology Baseline and Standard Scenarios post-2023 by mapping domestic gaps for components, identifying over 70% reliance on foreign blades and recommending policy-driven localization to mitigate tariffs or blockades. These updates employ network flow algorithms to trace vulnerabilities, such as shipping disruptions in 2024 that delayed deliveries by 15-20% globally. Supply chain modeling has advanced through dynamic input-output frameworks that quantify cascading effects from single-point failures, like China's 80% control of rare earth processing, which models simulate under tariffs or seizure scenarios. For instance, wavelet coherence analysis in 2024 research linked supply chain pressures to indices, showing that geopolitical events amplify disruptions by 1.5-2 times in renewable stock returns during periods of heightened U.S.- tensions. AI-driven predictive tools, applied to green energy storage systems, now forecast risks from dual geopolitical and shocks, optimizing rerouting and stockpiling to reduce vulnerability by 25% in simulated 2025-2030 horizons. Such enhancements, while improving granularity, remain limited by opacity in adversarial regimes, prompting hybrid models blending tracking with econometric proxies for real-time adjustments.

Updates in major models post-2023

The U.S. Energy Information Administration (EIA) conducted extensive revisions to its National Energy Modeling System (NEMS) throughout 2024, culminating in the release of the Annual Energy Outlook 2025 (AEO2025) on April 15, 2025. These updates focused on enhancing representations of emerging technologies, such as advanced nuclear and battery storage, and refining electricity sector dynamics to better capture supply-demand interactions and policy impacts. The revisions addressed limitations identified in prior iterations, including improved handling of electrification and flexibility, following the decision to forgo an AEO2024 release to prioritize model redevelopment. The (IEA) incorporated methodological enhancements into its World Energy Model (WEM) for the World Energy Outlook 2024, published on October 16, 2024. Key changes included expanded bottom-up analysis of clean energy deployment, with over 560 GW of new renewables capacity integrated into projections, alongside refined modules for risks and emissions trajectories under scenarios like Stated Policies (STEPS). The accompanying Global Energy and Climate Model documentation for 2024 emphasized granular industry surveys and updated supply-demand linkages for fossil fuels, electricity markets, and end-use sectors. In the Energy Technology Perspectives 2024 report, released October 30, 2024, the IEA introduced fresh modeling approaches with detailed technology-specific datasets and scenario tools to evaluate innovation pathways, including and carbon capture utilization and storage (CCUS). These updates featured probabilistic elements for technology maturation and cost trajectories, drawing on new empirical data to assess deployment barriers beyond historical linear extrapolations. The (NREL) updated its Annual Technology Baseline () and Standard Scenarios in early 2024, with the ninth edition of Standard Scenarios released on January 9, 2024, expanding to 53 U.S. electricity sector futures through 2050. Revisions incorporated revised renewable cost assumptions, updated network modeling via the reV tool (version 2023 with enhanced setback layers), and sensitivity to policy variations, aiming for greater alignment with observed 2023 deployment trends like 11.2 GWac of U.S. additions.

References

  1. [1]
    About Building Energy Modeling
    Building Energy Modeling (BEM) is a multi-purpose tool for building energy efficiency, supporting projects at the level of individual buildings (design, control ...
  2. [2]
    Energy Modeling - an overview | ScienceDirect Topics
    Energy modelling is a process of designing different computer-based energy systems for optimal configuration. Models are accessible tools in situations where ...
  3. [3]
    [PDF] The National Energy Modeling System: An Overview - EIA
    May 2, 2023 · In each model year, EMM receives electricity demand projections from the NEMS demand modules, fuel prices from the NEMS fuel supply modules, ...<|separator|>
  4. [4]
    EnergyPlus Turns 20! - Department of Energy
    Jul 17, 2021 · In 1996, DOE decided to create a state-of-the-art engine that would embody the latest and most advanced methods in building energy simulation.
  5. [5]
    [PDF] How Energy Modeling Works
    Mar 12, 2023 · Models are used because the systems they simulate are complex, yet these comparatively simple simulations make it easier to understand how ...
  6. [6]
    Energy Modeling Isn't Very Accurate - GreenBuildingAdvisor
    Mar 30, 2012 · According to Blasnik, most modeling programs aren't very accurate, especially for older buildings. Unfortunately, existing models usually aren't revised or ...
  7. [7]
    On the accuracy of Urban Building Energy Modelling - ScienceDirect
    This paper presents a systematic analysis of urban building energy models, that have been validated against measured data, using a singular taxonomy.
  8. [8]
    Simulation modeling for energy systems analysis: a critical review
    Aug 27, 2024 · The review identifies critical areas for improvement, including enhancing data quality, refining modeling techniques, and strengthening ...
  9. [9]
    The National Energy Modeling System: An Overview 2009 - EIA
    The National Energy Modeling System (NEMS) is a computer-based, energy-economy modeling system of U.S. through 2030.
  10. [10]
    Building Energy Modeling
    Whole-Building Energy Modeling (BEM) is a multipurpose tool for energy efficiency, supporting design, operations, codes and standards, and research.Missing: definition | Show results with:definition
  11. [11]
    Building Energy Modeling - NREL
    Jun 20, 2025 · Building energy modeling researchers develop multipurpose physics-based simulation software used in the prediction and analysis of building ...Missing: definition | Show results with:definition
  12. [12]
    [PDF] Introduction to Energy System Modelling - ICTP
    Energy modeling – a panacea for planning? ➢ Energy modeling is an art ... ➢ Fundamental energy system transformation is the only viable option.
  13. [13]
    [PDF] Power Sector Modeling 101 - Department of Energy
    • National Energy Modeling System (NEMS) – U.S. Energy Information Agency. • Regional Energy Deployment System (ReEDS) – National Energy Renewable. Laboratory.
  14. [14]
    Understanding the Current Energy Paradigm and Energy System ...
    The first simple linear programming energy models were developed in the 1960s. Since then, many more have been developed [6]. One category of energy models is ...
  15. [15]
    [PDF] A modeler's guide to handle complexity in energy systems optimization
    During the 1960s and 1970s, the rapidly growing energy demand, as well as an advancing liberation of the energy market [5, 6], drove the development of more ...
  16. [16]
    [PDF] Introduction to Energy Systems Modelling
    Historically, Computable General Equilibrium (CGE) models have their origins in the general equilibrium theory developed by Léon Walras1 in the 1870s,. Vilfredo ...
  17. [17]
    About | Energy Modeling Forum - Stanford University
    EMF was established at Stanford in 1976 to bring together leading experts and decisionmakers from government, industry, universities, and other research ...Missing: history | Show results with:history
  18. [18]
    Energy Demand and Modelling of Energy Systems: Five Decades ...
    Sep 26, 2024 · 3.2 First Generation of Technically Based Energy Models. Early bottom-up models emerged in the 1980s and quickly became more and more complex.
  19. [19]
    History of LEAP
    LEAP was originally created in 1980 for the Beijer Institute's Kenya Fuelwood Project, to provide a flexible tool for long-range integrated energy planning.
  20. [20]
    [PDF] Documentation for the MARKAL Family of Models - IEA-ETSAP
    This practice is in part inspired from historical custom from the days of the fixed demand MARKAL model. ... (1996), "MARKAL-Geneva: A Model to Assess Energy-.
  21. [21]
    Bottom-up energy modeling - eScholarship
    The bottom-up approach focuses on individual technologies for delivering energy services, such as household durable goods and industrial process technologies.
  22. [22]
    Classification and challenges of bottom-up energy system models
    This paper reviews the classification schemes used for bottom-up energy system modelling and proposes a novel one as re-elaboration of the previous schemes.
  23. [23]
    [PDF] A Comparison of Bottom-up and Top-down Modelling Approaches in ...
    This paper compares the results of energy demand simulation using. TRNSYS as a bottom-up building simulation software and the CEA toolbox as a simplified, top- ...
  24. [24]
    7.6.3 - IPCC
    Top-down models evaluate the system from aggregate economic variables, whereas bottom-up models consider technological options or project-specific climate ...
  25. [25]
    Energy efficiency to reduce residential electricity and natural gas ...
    May 15, 2017 · The advantage to bottom-up approaches is that end-uses can be directly predicted and targeted for improvement, at the disadvantage of having ...
  26. [26]
    Efficient coordination of top-down and bottom-up models for energy ...
    Dec 1, 2023 · Top-down macroeconomic models provide a holistic view of the economy but lack sector-specific details. On the other hand, bottom-up energy ...
  27. [27]
    [PDF] Classification of Energy Models - Tilburg University Research Portal
    In contrast, bottom-up models usually focus on the energy sector exclusively, and use highly disaggregated data to describe energy end-uses and technological ...
  28. [28]
    Hybrid Bottom-up/Top-down Energy and Economy Outlooks - Frontiers
    Bottom-up (BU) and top-down (TD) models of the energy systems have been opposed since at least Grubb et al. (1993), echoing even older distinctions dating back ...
  29. [29]
    Natural Gas Emissions: Measure Top-down or Bottom-up? - NREL
    Mar 10, 2025 · "Bottom-up" estimates measure emissions from a representative sample of devices. In contrast, "top-down" measurements can be performed at a ...
  30. [30]
    A review of optimization modeling and solution methods in ...
    Nov 22, 2023 · A review on planning, configurations, modeling and optimization techniques of hybrid renewable energy systems for off grid applications.
  31. [31]
    Energy Management Systems' Modeling and Optimization in Hybrid ...
    Energy management strategies aim to increase efficiency and performance by optimizing the power distribution between the engine and the electric motor in HEVs, ...
  32. [32]
    ‪Chiara Bordin, PhD‬ - ‪Google Scholar‬
    Next frontiers in energy system modelling: A review on challenges and the state of the art · A linear programming approach for battery degradation analysis and ...<|separator|>
  33. [33]
    Modeling and Simulation of Energy Systems: A Review - MDPI
    EE models typically work with long-term time scales for a couple of reasons: first, the capital intensiveness, long gestation periods, and long payback periods ...
  34. [34]
    Methods for Hybrid Modeling and Simulation-Based Optimization in ...
    This thesis presents a hybrid discrete/continuous modelling approach and simulation implementation based on the Discrete-Event System Specification (DEVS) for ...
  35. [35]
    HOMER Pro
    HOMER (Hybrid Optimization of Multiple Energy Resources) software navigates the complexities of building cost effective and reliable hybrid microgrid and grid- ...
  36. [36]
    A comprehensive review on optimization of hybrid renewable ...
    This paper aims to provide a succinct review of recent progress in the field of optimization of different HRES using various optimization techniques.
  37. [37]
    Hybrid System Modeling Approach for the Depiction of the Energy ...
    Jul 6, 2020 · Hybrid simulation uses sub-models (Production, Machine, Energy) to link energy consumption to machine behavior, which is influenced by material ...
  38. [38]
    Hybrid modeling approach for precise estimation of energy ... - Nature
    Oct 18, 2024 · This study introduces an advanced mathematical methodology for predicting energy generation and consumption based on temperature variations.<|separator|>
  39. [39]
    World Energy Outlook 2023 – Analysis - IEA
    Oct 24, 2023 · The World Energy Outlook 2023 provides in-depth analysis and strategic insights into every aspect of the global energy system.
  40. [40]
    Annual Energy Outlook 2025 - EIA
    Apr 15, 2025 · We prepared the AEO by using the National Energy Modeling System (NEMS) to project a set of scenarios that, taken together, represent a ...
  41. [41]
    How We Estimated Energy End-Use Consumption in the 2018 CBECS
    Apr 12, 2023 · In general, these models estimate the amount of energy used for each end use in a building based on the size of the building, the type of ...
  42. [42]
    [PDF] Bottom-Up Simulation Model for Estimating End-Use Energy ...
    The model simulates the usage of domestic appliances probabilistically over time in terms of consumed energy, based on the activities of the people in the house ...
  43. [43]
    Prototype Building Models | Building Energy Codes Program
    Prototype building models include commercial (16 types in 19 climates) and residential (single/multi-family, 4 heating/foundation types) models used for energy ...
  44. [44]
    End-Use Load Profiles for the U.S. Building Stock - NREL
    Jun 23, 2025 · The output of each building energy model is 1 year of energy consumption in 15-minute intervals, separated into end-use categories.
  45. [45]
    Modeling of end-use energy consumption in the residential sector
    The aim of this paper is to provide an up-to-date review of the various modeling techniques used for modeling residential sector energy consumption.<|separator|>
  46. [46]
    [PDF] Electricity Capacity Expansion Modeling, Analysis, and Visualization
    This report focuses on the experience at NREL, using primarily the Regional Energy. Deployment System (ReEDS) model for capacity expansion. There are many other ...
  47. [47]
    Power Sector Modeling | US EPA
    Power Sector Modeling provides information and documentation on EPA's power sector modeling resources and regulatory applications.
  48. [48]
    Electric Sector Model - US-REGEN Documentation - EPRI
    May 22, 2025 · The electric sector model outputs electricity prices that serve as an input to endogenous demand decisions in the end-use model. Demand ...
  49. [49]
    Power market models for the clean energy transition: State of the art ...
    Mar 1, 2024 · This paper provides a detailed overview of the properties of power market models in the context of the clean energy transition.
  50. [50]
    Integrated Energy Systems | Grid Modernization - NREL
    Mar 12, 2025 · Integrated energy system simulation is an approach in which researchers consider a multi-system energy challenge holistically rather than looking at each of ...Missing: methodology | Show results with:methodology
  51. [51]
    A systemic approach to analyze integrated energy system modeling ...
    Energy system optimization models use four main uncertainty analysis methods, which are Monte Carlo Simulation (MCS), Stochastic Programming (SP), Robust ...
  52. [52]
    A Comprehensive Review of Integrated Energy Systems ... - MDPI
    This article presents a comprehensive review of the state-of-the-art research and of the developments regarding integrated energy systems considering PtG ...
  53. [53]
    A systemic approach to analyze integrated energy system modeling ...
    Aug 28, 2020 · Reconciling top-down and bottom-up energy/economy models: a case of TIAM-FR and IMACLIM-R. Working Paper 2017-02-26. [Google Scholar]; 128 ...
  54. [54]
    A review of integrated energy system modeling and operation
    The primary objective of IES modeling is to accurately capture the flow and interaction of heterogeneous energy sources and to develop suitable models for a ...
  55. [55]
    [PDF] Integrated Energy Systems Modeling and Simulation
    Dynamic models developed in the Modelica language using the commercial platform Dymola from Dassault Systems. Low Carbon Products: Fuel, Chemicals, Metals, ...Missing: methodology | Show results with:methodology
  56. [56]
    Review A critical survey of integrated energy system
    Aug 15, 2022 · M.F. Tahir et al. A comprehensive review of 4E analysis of thermal power plants, intermittent renewable energy and integrated energy systems ...
  57. [57]
    Handbook of Energy Modeling Methods - EIA
    Oct 25, 2024 · EIA's new Handbook of Energy Modeling Methods explains, in plain language, the processes EIA uses to produce long- and short-term projections of key energy ...
  58. [58]
    Integrated Energy Systems Modeling with Multi-Criteria Decision ...
    Integrated Energy Systems Modeling with Multi-Criteria Decision Analysis and ... Davidsdottir has published 150+ academic peer reviewed publications.
  59. [59]
    How Do Energy-Economy Models Compare? A Survey of ... - MDPI
    Energy-economy modelling literature suggests three model types categorized by analytical approach: “bottom-up” technological models, “top-down” macroeconomic ...
  60. [60]
    [PDF] ENERGY-ECONOMY ANALYSIS Linking the Macroeconomic and ...
    This paper describes procedures that link economic models with systems engineering models. It is based on the modeling framework used for a number of ...
  61. [61]
    Computable General Equilibrium Models for the Analysis of Energy ...
    This Handbook offers a comprehensive review of the economics of energy, including contributions from a distinguished array of international specialists.
  62. [62]
    General Equilibrium Model - Economy, Energy, Environment
    A macro-economic model used to assess energy, climate and air quality policies. summary. The GEM-E3 model is a global multi-sectoral general equilibrium model.
  63. [63]
    An energy-based macroeconomic model validated by global ...
    In this paper we present a simple, energy-based macroeconomic model to study the world economy, as an essential step to unravel the economy-environment nexus.
  64. [64]
    How can computable general equilibrium models serve low-carbon ...
    Feb 24, 2023 · Computable general equilibrium (CGE) models have been widely employed in economic, social, and environmental impact assessments for low-carbon policies.<|control11|><|separator|>
  65. [65]
    Energy-Environment-Economy Global Macro-Economic (E3ME)
    E3ME is a global sectoral econometric model used to analyze long-term energy and environment interactions within the global economy.
  66. [66]
    [PDF] Macroeconomic Activity Module of the National Energy Modeling ...
    Jul 3, 2025 · EIA's version of S&P Global Market Intelligence's model of the U.S. economy, the Macroeconomic Model, provides estimates of over 1700 concepts.
  67. [67]
    EMF 1: Energy and the Economy
    The first EMF working group examined the link between energy and the economy, concentrating on the use of several large macroeconomic models.
  68. [68]
    LEAP: Low Emissions Analysis Platform
    LEAP, the Low Emissions Analysis Platform, is a versatile software system for energy policy analysis and climate change mitigation assessment.
  69. [69]
    LEAP: Long-range Energy Alternatives Planning System User Guide
    LEAP is a scenario-based energy-environment modeling tool. Its scenarios are based on comprehensive accounting of how energy is consumed, converted, and ...
  70. [70]
    LEAP - Long-range Energy Alternatives Planning System
    LEAP, the Long-range Energy Alternatives Planning System, is a widely-used scenario-based software tool, which supports a wide range of different modelling ...
  71. [71]
    Long-Range Energy Alternatives Planning System (LEAP)
    LEAP can be used to track energy consumption, production and resource extraction in all sectors of an economy. It can be used to account for both energy sector ...
  72. [72]
    [PDF] Long-range Energy Alternatives Planning System (LEAP ...
    On the supply side, it provides a range of accounting and simulation methodologies, as well as optimization modelling capabilities . LEAP's modelling operates ...
  73. [73]
    LEAP
    LEAP user Matthew Davis from the University of Alberta has developed a new AI-based energy modeling assistant for Chat-GPT called LEAP-GPT that is designed ...
  74. [74]
    [PDF] ENG-LEAP-TRAINING-MANUAL.pdf - Global Green Growth Institute
    • The Mongolia LEAP dataset contains a detailed energy system model, which models the demand for electricity and other fuels, and on the supply side models the.<|separator|>
  75. [75]
    The Long-range Energy Alternatives Planning - Integrated Benefits ...
    May 3, 2018 · This factsheet describes the key features of the LEAP-IBC tool. The Long-range Energy Alternatives Planning (LEAP) - Integrated Benefits ...
  76. [76]
    [PDF] Energy Planning and the development of carbon mitigation strategies
    MARKAL provides policy makers and planners in the public and private sector with extensive detail on energy producing and consuming technologies, and it can.
  77. [77]
    Markal - IEA-ETSAP
    MARKAL is a model representing energy system evolution over 40-50 years, using technology performance and cost characteristics to find least-cost solutions.
  78. [78]
    Markal, a linear‐programming model for energy systems analysis ...
    This model, MARKAL, is driven by useful energy demands, optimizes over several time periods collectively, and allows multiobjective analyses to be performed ...<|separator|>
  79. [79]
    [PDF] Energy/Environmental Modeling with the MARKAL family of Models
    Abstract. This article presents an overview and a flavour of almost two decades of. MARKAL model developments and selected applications. The MARKAL family.
  80. [80]
    ETSAP-TIAM: the TIMES integrated assessment model Part I
    Feb 24, 2007 · TIMES, and its global version ETSAP-TIAM, is a model for exploring energy systems and analyzing energy and environmental policies, derived from ...<|separator|>
  81. [81]
    etsap-TIMES/TIMES_model: The Integrated MARKAL ... - GitHub
    TIMES is a technology rich, bottom-up model generator, which uses linear-programming to produce a least-cost energy system, optimized according to a number of ...
  82. [82]
    Integrated MARKAL-EFOM System (TIMES) Model - NDC Partnership
    TIMES is a bottom-up model generator that uses linear-programming to produce a least-cost energy system, optimized according to a number of user constraints.
  83. [83]
    Times - IEA-ETSAP
    TIMES is a technology rich, bottom-up model generator, which uses linear-programming to produce a least-cost energy system, optimized according to a number of ...
  84. [84]
    How to learn MARKAL and TIMES energy modelling software?
    Feb 10, 2022 · Typical MARKAL models run in 3-10 minutes depending upon size and assuming a state-of-the-art LP (Linear Programming) optimizer.
  85. [85]
    [PDF] White Paper modelling - use of the Markal Energy Model - GOV.UK
    3. MARKAL is a bottom-up technology model of the energy system. It was initially developed by the International Energy Agency (IEA).
  86. [86]
    [PDF] Overview of the MARKAL/TIMES Energy Systems Modeling ...
    Encompasses an entire energy system from resource extraction through to end-use demands as represented by a Reference Energy System (RES) network.
  87. [87]
    Model Development - U.S. Energy Information Administration (EIA)
    NEMS is a modular system. The modules represent each of the fuel supply markets, conversion sectors, and end-use consumption sectors of the energy system. The ...
  88. [88]
    Integrating Module - NEMS Documentation - EIA
    Chapter 3 describes the NEMS global data structure, which is used for inter-module communication, solution initialization and storage, and certain database ...
  89. [89]
    National energy system optimization modelling for decarbonization ...
    Energy system optimization models (ESOMs) are the accurate tools to guide decision-making in national energy planning. This article presents a systematic ...
  90. [90]
    OSeMOSYS - Home
    OSeMOSYS is an open source modelling system for long-run integrated assessment and energy planning. It has been employed to develop energy systems models.Get started · Applications · About · Cypriot energy system
  91. [91]
    About - OSeMOSYS
    OSeMOSYS is a full-fledged systems optimization model for long-run energy planning. The initial working code of OSeMOSYS was published in 2008.
  92. [92]
    OSeMOSYS: The Open Source Energy Modeling System
    OSeMOSYS is a new free and open source energy systems. This model is written in a simple, open, flexible and transparent manner to support teaching.
  93. [93]
    Introduction to OSeMOSYS
    The Open Source energy MOdelling SYStem (OSeMOSYS) is specifically designed as a tool to inform the development of local, national and multi-regional energy ...
  94. [94]
    Get started - OSeMOSYS
    The Model Management Infrastructure (​MoManI), is an open source interface available for OSeMOSYS. All users are welcome to download and use the stand-alone ...
  95. [95]
    clicSAND for OSeMOSYS: A User-Friendly Interface Using ... - MDPI
    Aug 8, 2024 · A significant usability advantage is that no interaction with the command line is necessary during the modelling process. Furthermore, the ...
  96. [96]
    Applications - OSeMOSYS
    HUNDREDS of OSeMOSYS APPLICAIONS and PAPERS! They range from contributions to the IPCC, to UN and WBG discussion papers, to official national planning, ...Missing: advantages | Show results with:advantages
  97. [97]
    OSeMOSYS Global, an open-source, open data global electricity ...
    Oct 14, 2022 · This paper describes OSeMOSYS Global, an open-source, open-data model generator for creating global electricity system models for an active ...
  98. [98]
    OTHER APPLICATIONS - OSeMOSYS
    The OSeMOSYS tool was chosen as the development tool for its advantages in simplicity, accessibility, affordability and flexibility, making the model and its ...
  99. [99]
    Code exposed: Review of five open-source frameworks for modeling ...
    A comparison of five open-source energy system modeling frameworks (OS-ESMFs) oemof, GENeSYS-MOD, Balmorel, urbs and GENESYS-2 on the mathematical level.
  100. [100]
    Introduction — Calliope 0.6.10 documentation - Read the Docs
    OSeMOSYS: A simplified energy system model similar to the MARKAL/TIMES model families, which can be used as a stand-alone tool or integrated in the LEAP energy ...Missing: alternatives | Show results with:alternatives
  101. [101]
    Using Models in Energy Policymaking | Congress.gov
    Aug 20, 2020 · Energy system models estimate energy supply, demand, prices, and related factors over defined time periods. Energy system models are not one- ...
  102. [102]
    [PDF] The Use of NEMS in Energy Policy Analysis: An Annotated ...
    Jan 24, 2014 · The National Energy Modeling System (NEMS) is used by the Energy Information. Administration (EIA) to forecast US energy production, consumption ...
  103. [103]
    [PDF] Documentation for the TIMES Model PART I - IEA-ETSAP
    GAMS is a modeling language that translates a TIMES database into the Linear Programming matrix, and then submits this. LP to an optimizer and generates the ...
  104. [104]
    JRC TIMES energy system model for the EU
    The JRC-EU-TIMES model produces projections (or scenarios) of the EU energy system showing its evolution up to 2050 under different sets of specific ...
  105. [105]
    [PDF] Quantitative assessments of NEGEM scenarios with TIMES-VTT
    TIMES-VTT model has been the core tool in formulating and analysing the impacts of Finland's climate and energy strategies and policies, including climate ...
  106. [106]
    Model-based policymaking or policy-based modelling? How energy ...
    In such best case usage, energy models inform governmental decision-making processes and help policymakers navigate an uncertain future [12], although model ...
  107. [107]
    How does energy modelling influence policymaking? Insights from low
    This research examines the experiences of developing and using energy system models that support decision-making in LMICs.
  108. [108]
    Unpacking the modeling process for energy policy making - Lo Piano
    Nov 14, 2023 · This article explores how the modeling of energy systems may lead to an undue closure of alternatives by generating an excess of certainty ...
  109. [109]
    Resource Planning Model | Energy Systems Analysis - NREL
    Apr 21, 2025 · The Resource Planning Model (RPM) is a capacity expansion model designed for a regional power system, such as a utility service territory, state, or balancing ...
  110. [110]
    Understanding Power System Model Results for Long-Term ...
    A two-part informational guide to help stakeholders understand power system model results and contribute to the development of integrated resource plans (IRPs).
  111. [111]
    [PDF] Best Practices in Integrated Resource Planning
    Figure 3 illustrates a typical IRP modeling structure. Planners conduct separate studies when necessary to generate forecasts, which become key input parameters ...
  112. [112]
    What's the State of Utility Planning Halfway through 2024? - RMI
    Jul 12, 2024 · This article is one of a series in our review of all integrated resource plans (IRPs) for electric utilities across the United States.
  113. [113]
    TIMES-DK: Technology-rich multi-sectoral optimisation model of the ...
    This article describes design, input data and current usage of TIMES-DK, the first Danish energy system model that includes the complete national energy system, ...<|control11|><|separator|>
  114. [114]
    [PDF] TIMES modeling for International Electricity Markets - EIA
    Jan 15, 2015 · TIMES modeling is used for international electricity markets, with inputs like energy demands and outputs like technology investments and  ...
  115. [115]
    Assessing decarbonization pathways for energy-intensive industries ...
    The study uses TIMES model to assess decarbonization pathways, finding that CCUS contributes 33% of emission reduction, and 62% of fossil fuel must be replaced ...
  116. [116]
    Energy systems in scenarios at net-zero CO 2 emissions - Nature
    Oct 20, 2021 · Here, we examine the energy systems of 177 net-zero scenarios and discuss their long-term technological and regional characteristics in the ...Results · Residual Emissions And... · Regional Energy Use, Energy...
  117. [117]
    Net Zero by 2050 – Analysis - IEA
    May 18, 2021 · In the net zero pathway, global energy demand in 2050 is around 8% smaller than today, but it serves an economy more than twice as big and a ...Missing: critiques | Show results with:critiques
  118. [118]
    TIMES-Europe: An Integrated Energy System Model for Analyzing ...
    Jul 18, 2024 · This paper introduces TIMES-Europe, a novel integrated multi-sectoral energy system optimization model for Europe based on the TIMES generator.<|control11|><|separator|>
  119. [119]
    Decarbonizing the US Energy System - Annual Reviews
    In this review, we identify key decarbonization analysis gaps and opportunities, including issues related to cross-sectoral linkages, spatial and temporal ...
  120. [120]
    Review of model-based electricity system transition scenarios
    Policymakers currently face the challenge of supporting a suitable technology mix to decarbonize electricity systems.
  121. [121]
    [PDF] A Critical Assessment of the IEA's Net Zero Scenario, ESG, and the ...
    This report examines the feasibility of the IEA's assumptions behind its Net Zero by 2050. (NZE) scenario and its implications for oil and gas production, ...
  122. [122]
    Net-zero CO2 by 2050 scenarios for the United States in the Energy ...
    All models show a reliance on negative emissions technologies to achieve net zero carbon dioxide emissions. Abstract. The Energy Modeling Forum (EMF) 37 study ...
  123. [123]
    Model-based net-zero scenarios, including those of the IPCC, aren't ...
    Jun 10, 2022 · Systematic underestimation of future damages; · Unjustifiably high discount rates; · One-sided assumptions about carbon prices being the primary ...
  124. [124]
    Politically feasible decarbonization pathways for the United States
    We then implement sectoral policy portfolios in the US-TIMES model and compare them to a business-as-usual (BAU) scenario and an 80% system-wide decarbonization ...
  125. [125]
    Empirical validation of building energy simulation model input ...
    This paper presents a critical advancement in Building Energy Modeling (BEM) through an empirical validation approach using a high-quality dataset from a ...
  126. [126]
    Hindcasting to inform the development of bottom-up electricity ...
    Jun 15, 2023 · Hindcasting is hence valuable for developing bottom-up, technology-rich energy system models by informing how accurate the models are, raising ...
  127. [127]
    Global energy model hindcasting - IDEAS/RePEc
    This paper performs energy model hindcasting which compared the historical energy simulation results with the observations.
  128. [128]
    Multi-Model Approach of Global Energy Model Validation
    The Integrated MARKAL-EFOM System (TIMES) model is a bottom-up model generator that uses linear programming to create optimized lowest-cost energy systems ...
  129. [129]
    Understanding errors in EIA projections of energy demand
    This paper investigates the potential for systematic errors in the Energy Information Administration's (EIA) widely used Annual Energy Outlook.
  130. [130]
    3. NEMS Architecture | The National Energy Modeling System
    The proposed NEMS should be designed for simulations and analysis relating to the mid-term time horizon, up to about 25 years in the future. While such a ...
  131. [131]
    Accuracy of past projections of US energy consumption
    Projections 10–13 years into the future have had an average error of about 4%, and about half that for shorter time horizons. These errors mask much larger, ...
  132. [132]
    Annual Energy Outlook Retrospective Review - EIA
    Sep 14, 2022 · The AEO Retrospective shows the relationship between past AEO projections and actual energy indicators, and it informs discussions about the ...
  133. [133]
    Historical Variation of IEA Energy and CO2 Emission Projections
    In this work we analyzed thirteen sets of World Energy Outlook projections from the last 25 years. Different scenarios were considered for the following regions ...
  134. [134]
    Accuracy assessment of energy projections for China by Energy ...
    This study investigates accuracy of China's reference energy projections in the annual reports of IEO and WEO from 2004 to 2019.
  135. [135]
    [PDF] CEEP-BIT WORKING PAPER SERIES Why did the historical energy ...
    energy demand while population forecasting error is rather small and weakly related with energy demand ... Energy models for demand forecasting—A review.
  136. [136]
    Why did the historical energy forecasting succeed or fail? A case ...
    Unfortunately, some of its predictions succeeded while others failed. We in this paper attempt to decompose the leading source of these errors quantitatively.
  137. [137]
    An Evaluation of Errors in US Energy Forecasts: 1982–2003
    Aug 5, 2025 · This paper explores US energy forecasts in order to uncover potential systemic errors in US forecasting models. We apply an error decomposition ...
  138. [138]
    [PDF] Quantifying Uncertainty in PV Energy Estimates Final Report - NREL
    Solar resource uncertainty represents one of the largest sources of uncertainty in annual energy modeling, and therefore the methods developed here includes ...<|separator|>
  139. [139]
    Linearization method for MINLP energy optimization problems - PMC
    Jul 30, 2025 · However, while linear models enable tractable formulations, they fail to capture the nonlinear characteristics of component efficiency curves, ...
  140. [140]
    UQ in Future Energy Systems - Uncertainty Quantification
    Due to the stochastic nature of renewable energy generation, spatial and temporal uncertainties of electricity generation increase and forecasting errors have ...
  141. [141]
    Tackling the multitude of uncertainties in energy systems analysis by ...
    This paper identifies and addresses three key challenges in energy systems analysis—varying assumptions, computational limitations, and coverage of a few ...
  142. [142]
    A review of approaches to uncertainty assessment in energy system ...
    We have identified four prevailing uncertainty approaches that have been applied to ESOM type models: Monte Carlo analysis, stochastic programming, robust ...
  143. [143]
    [PDF] Elastic Demand and Sensitivity Analysis in MARKAL/TIMES
    MARKAL and TIMES are model “shells”. We tailor the model to CA – thus, data driven. Rich in “bottom-up” technological detail – describes in detail technology ...
  144. [144]
    A framework for Global Sensitivity Analysis in long-term Energy ...
    Oct 7, 2025 · This paper introduces a framework for applying global parametric sensitivity analyses to energy system optimization models.
  145. [145]
    Global sensitivity analysis to enhance the transparency and rigour of ...
    The paper shows that using global sensitivity analysis provides added insights to those who develop and use energy system models. The approach can identify ...
  146. [146]
    Sensitivity to energy technology costs: A multi-model comparison ...
    Results of sensitivity analysis of energy technologies for three energy-economic models. •. In-depth analysis of sign of change and key-uncertainty drivers ...Missing: MARKAL | Show results with:MARKAL
  147. [147]
    The Value of Global Sensitivity Analysis for Energy System Modelling
    Jan 26, 2018 · Most energy system models are analysed using sensitivity scenarios, a crude, local and subjective one-at-a-time approach to sensitivity ...
  148. [148]
    A modeler's guide to handle complexity in energy systems optimization
    Nov 19, 2021 · During the 1960s and 1970s, the rapidly growing energy demand, as well as an advancing liberation of the energy market [5, 6], drove the ...
  149. [149]
    The misuse and abuse of climate pathways and scenarios
    Distorting the view of our climate future: The misuse and abuse of climate pathways and scenarios. Author links open overlay panel. Roger Pielke Jr. a
  150. [150]
    [PDF] Perils of Long-Range Energy Forecasting - Vaclav Smil
    I underestimated both the use of natural gas and crude oil (by, respectively, 25 and 12%), and I overestimated the contributions of coal and renewable energies.
  151. [151]
    Where Energy Modeling Goes Wrong | Our Finite World
    Feb 3, 2021 · Intermittent renewables are far ahead of fossil fuels in terms complexity: they require sophisticated systems of storage and distribution ...
  152. [152]
    Geophysical constraints on the reliability of solar and wind power ...
    Oct 22, 2021 · Under these generation and storage assumptions, the most reliable solar-wind generation mixes range from 65 to 85% wind power (73% on average), ...
  153. [153]
    Uncertainties in estimating production costs of future nuclear ...
    Oct 15, 2023 · We present a unique cost data set on 19 small modular reactors. Manufacturer cost estimates are mostly too optimistic compared to production theory.
  154. [154]
    [PDF] The Future of Nuclear Energy in a Carbon-Constrained World
    The least-cost portfolios include an important share for nuclear, the magnitude of which significantly grows as the cost of nuclear drops. (Figure E.1, right ...
  155. [155]
    Nuclear Bias in Energy Scenarios – A Review and Results from an ...
    Nuclear is often modelled as a baseload technology because flexibility options for renewables-based systems are underestimated.
  156. [156]
    Beyond Magical Thinking: Time to Get Real on Climate Change
    May 19, 2022 · Energy scientist Vaclav Smil says it's time to stop ricocheting between apocalyptic forecasts and rosy models of rapid CO2 cuts.
  157. [157]
    Planning reliable wind- and solar-based electricity systems
    Flexible, dispatchable generation has been shown to substantially reduce electricity costs in systems heavily dependent on variable renewable generation [31].Missing: IAMs | Show results with:IAMs
  158. [158]
    System Integration of Wind and Solar Power in ... - ResearchGate
    Aug 7, 2025 · ... Generally, IAMs suffer from a low spatial and temporal resolution that prevents the representation of energy networks and the variability of ...
  159. [159]
    Transparency, trust, and integrated assessment models: An ethical ...
    Oct 8, 2020 · Critical assumptions and structural biases are not always readily apparent to the outside observer.” Due to the opaque nature of IAMs, the ...
  160. [160]
    Modeling Intermittent Renewable Energy: Can We Trust Top-Down ...
    New modeling challenges brought about by intermittent renewable energy sources, however, require to carefully review existing tools. This paper provides an ...Missing: assumptions favoring
  161. [161]
    [PDF] Towards Increased Policy Relevance in Energy Modeling - OSTI
    We identify research priorities for the modeling framework, technology representation in models, policy evaluation and modeling of decision-making behavior.
  162. [162]
    The ethos of energy modeling in an era of transition - ScienceDirect
    Energy systems and their transitions can be analyzed from three perspectives: techno-economic, socio-technical and political [2]. The techno-economic ...
  163. [163]
    Improving Prediction of Energy Futures
    Policymakers need to understand the limitations and biases of models, and modelers need to admit that energy projections have not been particularly accurate.<|separator|>
  164. [164]
    The Social Cost of Carbon: A Flawed Measure for Energy Policy
    Apr 23, 2025 · In short, the SCC is used to justify far higher energy costs today. Furthermore, the economic and environmental damages caused by de- ...
  165. [165]
    NCEA Report Urges Policymakers to Reject Flawed “Social Cost of ...
    Apr 23, 2025 · – Higher energy costs: Policies based on inflated SCC values lead to higher electricity and fuel prices, disproportionately affecting lower- ...<|separator|>
  166. [166]
    Energy Subsidies - World Nuclear Association
    May 7, 2024 · Government can require private actors such as electricity consumers to pay subsidies by creating corresponding regulations or legislation.
  167. [167]
    The role of energy subsidies, savings, and transitions in driving ...
    Apr 1, 2025 · The research addresses the fundamental issue regarding how energy subsidies affect energy transformations toward achieving net-zero emissions.
  168. [168]
    Efficiency and Equity Impacts of Energy Subsidies
    Economic theory suggests that energy subsidies can lead to excessive consumption and environmental degradation.
  169. [169]
    Multi-model comparison of the economic and energy implications for ...
    Direct and macro-economic costs of climate policy ... For China, climate policy costs decrease in the energy system models and increase in the CGE models.
  170. [170]
    Bias in energy system models with uniform cost of capital assumption
    Oct 9, 2019 · While the time value of money might be uniform, the risk premium for long-term investments varies due to differences in macroeconomic stability, ...
  171. [171]
    Policy insights from comparing carbon pricing modeling scenarios
    The economic costs of the policies are expected to be modest – allowing for nearly identical economic growth– but vary across models. These costs are offset by ...
  172. [172]
    “Low probability, if not impossibility” of reaching net-zero emissions ...
    Mar 27, 2024 · This is a condensed version of a new essay by globally renowned energy expert Vaclav Smil that was first published in JP Morgan's 14 th Annual Energy Paper.
  173. [173]
    Why everyone missed solar's exponential growth
    Nov 20, 2024 · Here's a shocking reality check: every major energy forecaster has been wrong about solar power uptake.
  174. [174]
    Digitalization and Energy – Analysis - IEA
    Nov 5, 2017 · The report examines the impact of digital technologies on energy demand sectors, looks at how energy suppliers can use digital tools to improve ...
  175. [175]
    Modeling myths: On DICE and dynamic realism in integrated ...
    Feb 2, 2021 · We analyze how stylized Integrated Assessment Models (IAMs), and specifically the widely-used Dynamic Integrated Climate-Economy model (DICE), represent the ...1 Introduction · 4.2 The Innovation Gap In... · 5 Path Dependence
  176. [176]
    Assessing the realism of clean energy projections - RSC Publishing
    Jun 18, 2024 · In this contribution, we critically examine IAM limitations in the context of clean energy technologies and critical materials.
  177. [177]
    The state of macro-energy systems research: Common critiques ...
    Mar 5, 2023 · The policy realism critique can be discussed in two parts: 1) the realism of policy instruments represented in MES models, and 2) the ...Missing: debates | Show results with:debates
  178. [178]
    Machine learning as a surrogate model for EnergyPLAN
    Oct 30, 2024 · This study aims to address this issue by integrating machine learning algorithms with EnergyPLAN and EPLANopt, a coupling of EnergyPLAN software ...
  179. [179]
    Energy and AI – Analysis - IEA
    Apr 10, 2025 · This report from the International Energy Agency (IEA) aims to fill this gap based on new global and regional modelling and datasets.
  180. [180]
    AI-Driven Decarbonization → Term - Prism → Sustainability Directory
    Sep 3, 2025 · AI enhances IAMs by improving their predictive power and enabling more granular scenario generation.<|control11|><|separator|>
  181. [181]
    Machine learning applications in energy systems: current trends ...
    May 7, 2025 · The primary factors that incorporate AI are renewable energy technologies, such as energy forecasting, energy efficiency, and energy access. The ...
  182. [182]
    Recent advances and applications of machine learning in the ...
    ML streamlines renewable energy systems, boosting efficiency and production, as global adoption necessitates precise forecasts for sustainable energy generation ...
  183. [183]
    (PDF) Geopolitical risks in energy system models: hindcasting in 31 ...
    Sep 5, 2025 · Here, we integrate five indices reflecting geopolitical risks into national electricity system models in 31 European countries and use ...
  184. [184]
    Exploring the connection between geopolitical risks and energy ...
    This study delves into the complexities of energy commodity futures and clean energy indexes, analyzing their responses to geopolitical risk.
  185. [185]
    Executive Summary – World Energy Outlook 2024 – Analysis - IEA
    Continued growth in global energy demand post-2030 can be met solely with clean energy. Annual energy and electricity demand growth, historical and in the ...Missing: accuracy | Show results with:accuracy
  186. [186]
    NREL Releases the 2023 Standard Scenarios
    Jan 9, 2024 · NREL's ninth installment of the Standard Scenarios includes 53 possible futures for how the US electricity sector could evolve through 2050.
  187. [187]
    Supply Chain Roadmap | Wind Research - NREL
    Supply Chain Roadmap. An NREL-led study evaluated how the U.S. can establish and build a robust domestic supply chain to support the wind energy industry.
  188. [188]
    Assessing Progress in Building Clean Energy Supply Chains
    Mar 3, 2025 · This technical paper provides an assessment of the progress that the United States and its partners have made in building de-risked clean energy supply chains.
  189. [189]
    Understanding supply chain constraints for the US clean energy ...
    Sep 30, 2025 · The following analysis addresses these concerns by examining trade dependencies and potential disruptions stemming from geopolitical tensions.
  190. [190]
    How do supply chain and geopolitical risks threaten energy security ...
    Feb 1, 2025 · This study unveils the correlation between the global supply chain and energy security in the presence of geopolitical risks using wavelet analysis.
  191. [191]
    Predictive Risk Modeling Under Geopolitical and Climate Shocks 2024
    Aug 18, 2025 · This study proposes an AI-optimized framework for dynamic supply chain mapping, tailored specifically for the green energy storage sector. By ...
  192. [192]
    Global Energy Outlook 2025: Headwinds and Tailwinds in the ...
    Apr 7, 2025 · In this report, we apply a detailed harmonization process to compare 13 scenarios across seven energy outlooks published in 2024 (and two ...
  193. [193]
    Annual Energy Outlook 2025 Model Development - EIA
    In 2024, we conducted extensive model development to support the Annual Outlook 2025. As part of that process, we developed these resources for the public.
  194. [194]
    World Energy Outlook 2024 – Analysis - IEA
    Oct 16, 2024 · The IEA's flagship World Energy Outlook, published every year, is the most authoritative global source of energy analysis and projections.
  195. [195]
    [PDF] Global Energy and Climate Model Documentation 2024 - NET
    The IEA examines the full spectrum of energy issues including oil, gas and coal supply and demand, renewable energy technologies, electricity markets,.
  196. [196]
    Energy Technology Perspectives 2024 – Analysis - IEA
    Oct 30, 2024 · This year's edition offers cutting-edge analysis based on rich and detailed new data, granular surveys of industry, and a bottom-up approach to fresh modelling.
  197. [197]
    Changes in 2023 | Electricity - ATB | NREL
    The update of the 2022 ATB to the 2023 ATB includes general updates to all technologies as well as technology-specific updates—both of which are described on ...Missing: IEA | Show results with:IEA