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IEA (2025), Global Energy and Climate Model, IEA, Paris https://www.iea.org/reports/global-energy-and-climate-model, Licence: CC BY 4.0
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Understanding GEC Model scenarios
Overview
The IEA’s medium- to long-term outlook publications – including the World Energy Outlook (WEO) and Energy Technology Perspectives (ETP) – use a scenario approach relying on the Global Energy and Climate (GEC) Model to examine future energy trends.
Each scenario has the same starting point and is based on the latest data for energy supply and demand, markets, technology costs and policies, as well as the same pathways for future population and economic growth.
The energy system described and explored in each scenario evolves in a distinctive pathway that delivers energy services with a different mix of technologies and fuels, with varying implications for energy security, affordability and emissions. This is primarily due to differing assumptions about how energy policies are implemented and evolve, and how these interact with the evolution of energy technologies and markets. By comparing the WEO scenarios, readers can assess what drives the various outcomes, and the opportunities and pitfalls that lie along the way. None of the individual WEO scenarios should be regarded as a forecast, and do not contain a single view about what the long-term future might hold. Instead, the scenarios seek to enable readers to compare different possible versions of the future, and the levers and actions that produce them, and to gain insights into the future of global energy.
The Current Policies Scenario (CPS) and the Stated Policies Scenario (STEPS) are exploratory, in that they define a set of starting conditions, such as policies and targets, and see where they lead based on model representations of energy systems that reflect market dynamics and technological progress.
In addition, we include three scenarios that have normative elements relating to energy access or the achievement of various goals related to emissions. This means that these scenarios work toward a defined outcome and map out a way to achieve it. The Accelerating Clean Cooking and Electricity Services Scenario (ACCESS) - an additional scenario included for the first time in the WEO-2025 - represents a roadmap to achieve universal access to electricity by 2035 and clean cooking by 2040. The Net Zero Emissions by 2050 Scenario shows a global pathway to reach net zero emissions from the energy sector by 2050 without offsets from other sectors, an emissions trajectory consistent with keeping the temperature rise in 2100 below 1.5 °C (with at least a 50% probability).
Definitions of the GEC Model 2025 scenarios
|
Scenario |
Definition |
|---|---|
|
Current Policies Scenario |
A scenario setting out a pathway for the future of the energy system in which no change in energy-related policies is assumed beyond what is already in place. The CPS therefore builds on a narrow reading of today’s policy settings, only considering those that are adopted in legislation and regulation, and assuming no change, even where governments have indicated their intention to do so. Where existing policies target a range of outcomes, it is assumed that the lower end of the range is achieved. In the CPS, policies that are time-bound or that target specific years are not strengthened after they expire. Alongside this view of the policy landscape, the CPS also offers a generally cautious perspective on the speed at which new energy technologies are deployed and integrated into the energy system. It tends to project slower growth in the adoption of new technologies in the energy system than seen in recent years, or than projected in the STEPS. |
|
Stated Policies Scenario |
A scenario which builds on a broader reading of the policy landscape than the CPS, also taking account of those policies that have been formally tabled but not yet adopted as well as other official strategy documents that indicate the direction of travel. These could include, for example, development plans for the power sector that aim to achieve a certain mix of generation assets by a specific date; or plans to reform the regulatory framework for part of the transport sector or to achieve a certain level of efficiency for new or retrofitted buildings. Such targets are not automatically assumed to be met; the prospects and timing for their realisation are subject to an assessment of relevant market, infrastructure and financial constraints. Another difference with the CPS relates to time-bound policies. Whereas the CPS assumes no further change in a policy once it expires, the STEPS assumes that time-bound policies are prolonged into the future and retain a similar pace of change. In addition, the STEPS offers a more dynamic perspective on energy technology and market trends, and it allows for a slightly more rapid introduction of new energy technologies than the CPS. However, like the CPS, the STEPS does not assume that aspirational goals, such as those included in the Paris Agreement, are achieved. |
|
Accelerating Clean Cooking and Electricity Services Scenario |
ACCESS is a data-driven roadmap to achieve universal access to electricity by 2035 and clean cooking by 2040. It is grounded in practical constraints and solutions, examining what historical rates of progress have been achieved in the past, and then prioritises cost-effective, proven means to replicate those successes. It explores all relevant fuels and technologies needed to achieve universal access as well as the infrastructure, policies and financing needed to scale them up. |
|
Net Zero Emissions by 2050 Scenario |
A scenario which maps out a pragmatic but ambitious global pathway for the energy sector to achieve net zero CO2 emissions by 2050 and is consistent with a long-term goal of limiting the rise in global average temperatures to 1.5 °C (with a 50% probability). In contrast with previous editions of the WEO, the NZE Scenario is no longer a limited-overshoot scenario, as warming peaks above 1.6 °C and exceeds 1.5 °C for several decades before returning below 1.5 °C by 2100. These changes in the scenario trajectory reflect the reality of persistently high emissions in recent years and slow or uneven momentum behind the deployment of some policies and technologies. In addition to very rapid progress with the transformation of the energy sector, bringing the temperature rise back down below 1.5 °C by 2100 also requires widespread deployment of CO2 removal technologies that are currently unproven at large scale. |
|
Announced Pledges Scenario |
The WEO-2025 does not include the Announced Pledges Scenario. Our assessment of the new round of Nationally Determined Contributions (NDCs) due this year, generally covering , will follow once there is a more complete picture of these pledges. In the WEO-2024, the APS assumes that all climate commitments made by governments and industries around the world as of the end of August 2024, including NDCs and longer-term net zero targets, as well as targets for access to electricity and clean cooking, will be met in full and on time. |
The scenarios highlight the importance of government policies in determining the future of the global energy system: decisions made by governments are a critical differentiating factor explaining the variations in outcomes across our scenarios. However, we also account for other elements and influences, notably the economic and demographic context, technology costs and learning, energy prices and affordability, corporate sustainability commitments, and social and behavioural factors. While the evolving costs of known technologies are modelled in detail, we do not try to anticipate technology breakthroughs (such as nuclear fusion).