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. The GEC Model is used to explore various scenarios, each of which is built on a different set of underlying assumptions about how the energy system might evolve over time. By comparing them, readers can assess what drives the various outcomes, and the opportunities and pitfalls that lie along the way. These scenarios are not predictions, 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 World Energy Outlook, Energy Technology Perspectives and their related reports explore different aspects of three scenarios, all of which are fully updated to include the latest energy market and cost data. The Net Zero Emissions by 2050 Scenario (NZE Scenario) is normative, in that it is designed to achieve specific outcomes – an emissions trajectory consistent with keeping the temperature rise in 2100 below 1.5 °C (with at least a 50% probability) with limited overshoot, universal access to modern energy services by 2030 and major improvements in air quality – and shows a pathway to reach them. The Announced Pledges Scenario (APS) 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.

Definitions and objectives of the GEC Model 2023 scenarios


Net Zero Emissions by 2050 Scenario 

Announced Pledges Scenario 

 Stated Policies Scenario 


A scenario which sets out a pathway for the global energy sector to achieve net zero CO2 emissions by 2050. It does not rely on emissions reductions from outside the energy sector to achieve its goals. Universal access to electricity and clean cooking are achieved by 2030. The scenario was fully updated in 2023.

A scenario which assumes that all climate commitments made by governments and industries around the world as of the end of August 2023, including Nationally Determined Contributions (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.

A scenario which reflects current policy settings based on a sector-by-sector and country-by-country assessment of the energy-related policies that are in place as of the end of August 2023, as well as those that are under development. The scenario also takes into account currently planned manufacturing capacities for clean energy technologies.


To show what is needed across the main sectors by various actors, and by when, for the world to achieve net zero energy-related CO2 emissions by 2050 while meeting other energy-related sustainable development goals such as universal energy access.

To show how close current pledges get the world to the target of limiting global warming to 1.5 °C. The differences between the APS and the NZE Scenario highlight the “ambition gap” that needs to be closed to achieve the goals of the Paris Agreement adopted in 2015. It also shows the gap between current targets and achieving universal energy access.

To provide a benchmark to assess the potential achievements (and limitations) of recent developments in energy and climate policy. The differences between the STEPS and the APS highlight the “implementation gap” that needs to be closed for countries to achieve their announced decarbonisation targets.

The scenarios highlight the importance of government policies in determining the future of the global energy system: decisions made by governments are the main 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).

How do the scenarios relate to the pursuit of a 1.5 °C outcome?

The Intergovernmental Panel on Climate Change (IPCC) Working Group III Sixth Assessment Report on climate change mitigation, released in April 2022, assessed a large number of scenarios that led to at least a 50% chance of limiting the temperature rise to 1.5 °C in 2100. As the figure makes clear, the NZE Scenario trajectory is well within the envelope of these scenarios.

To achieve the goal of limiting temperature rise, the Paris Agreement calls for emissions to peak as soon as possible and decline rapidly thereafter, leading to a balance between anthropogenic emissions by sources and removals by sinks (i.e. net zero emissions) by the year 2050. These conditions are all met in the NZE Scenario.

An integrated approach to energy and sustainable development in the Net Zero Emissions by 2050 Scenario

The Paris Agreement is clear that climate change mitigation objectives should be fulfilled in the context of sustainable development and efforts to eradicate poverty. The NZE Scenario explicitly supports these broader development efforts, in particular with respect to energy access and air pollution. In the NZE Scenario, there is no trade-off between achieving climate objectives and delivering on energy access and air pollution goals. Good policy design can exploit synergies between the three parallel objectives of the scenario.

Universal access to modern energy is achieved by 2030 in the NZE Scenario. Strong policy support and international co-operation enable a ramping-up of progress on expanding access programmes to achieve universal access to electricity and clean cooking by 2030, in line with Sustainable Development Goal 7. Achieving universal energy access will transform the lives of hundreds of millions of people and reduce the severe health impacts of indoor air pollution, overwhelmingly caused by smoke from cooking. Achieving universal access to modern energy leads to a net reduction in greenhouse gas emissions, largely thanks to lower methane emissions from the traditional use of biomass.

Countries with targets for access to electricity and clean cooking as considered in the APS

Access to electricity

Access to clean cooking

Universal access by 2030

Other targets

Universal access by 2030

Other targets


Angola, Benin, Botswana, Burundi, Cabo Verde, Cameroon, Côte d’Ivoire, Eritrea, Ethiopia, Gambia, Ghana, Guinea, Kenya, Liberia, Mauritania, Mozambique, Nigeria, Rwanda, Senegal, United Republic of Tanzania (Tanzania), Togo, Zambia

Burkina Faso, Central African Republic, Chad, Republic of the Congo (Congo), Djibouti, Democratic Republic of the Congo (DRC), Equatorial Guinea,
Guinea-Bissau, Lesotho, Madagascar, Malawi, Mali, Namibia, Niger, Sierra Leone, Somalia, South Sudan, Sudan, Uganda, Zimbabwe

Angola, Kingdom of Eswatini, Kenya, Malawi, Mali, Mozambique, Rwanda, Sudan

Benin, Botswana, Burkina Faso, Burundi, Cabo Verde, Cameroon, Côte d’Ivoire, DRC, Ethiopia, Ghana, Guinea, Guinea-Bissau, Liberia, Madagascar, Mauritania, Niger, Nigeria, Senegal, Sierra Leone, Tanzania, Togo, Uganda, Zimbabwe

Developing Asia

Myanmar, Nepal, Pakistan

Cambodia, Papua New Guinea

Bangladesh, China, Fiji, India, Indonesia, Mongolia, Myanmar, Nepal, Viet Nam

Bhutan, Pakistan, Philippines, Thailand

Central and South America

Bolivia, Dominican Republic, Ecuador, El Salvador, Guatemala, Honduras, Nicaragua, Panamá, Peru, Trinidad and Tobago


Colombia, Peru

Haiti, Honduras, Guatemala, Mexico, Nicaragua

Notes: Universal access by 2030 includes countries that have targets to reach 100% access rates by 2030 or before. Other targets include countries with other less ambitious targets. Includes only targets for countries with access rates lower than 99%.

Source: IEA analysis based on official country and third-party publications.

In the APS, all country targets for access to electricity and clean cooking (see table above) are achieved on time and in full. By 2030 this leads to a 60% and 68% reduction in the share of the population without access to electricity and clean cooking, respectively. However, this would still mean that there are 290 million people without access to electricity and 780 million without access to clean cooking.

Population without access to clean cooking by scenario, 2022 and 2030


Population without access to electricity by scenario, 2022 and 2030


Polluted air has caused at least 19 000 excess deaths per day in recent years and comes with significant economic costs. Some are direct costs, such as those due to the provision of healthcare, and some are indirect, such as those incurred because of labour productivity losses or crop damage.

While the STEPS and the APS see rising numbers of people exposed to heavily polluted air during the next decade, the NZE Scenario leads to dramatic reductions as set out in Sustainable Development Goal 3 (target 3.9). By 2050, around 2 billion fewer people breathe heavily polluted air.

Share of population exposed to high levels of air pollution by scenario, 2022-2050


Nearly two decades of clean energy transition scenarios

The IEA began exploring scenarios to limit CO2 emissions in 2006, with the ETP Accelerated Technology (ACT) Scenarios that sought to curb emissions growth by bringing emissions back down to 2005 levels by 2050. This analysis continued with the ETP BLUE Map Scenario in 2008, which targeted a 50% reduction in CO2 emissions by 2050, and later evolved into the 2 °C Scenario (2DS).

Several special reports designed to feed into United Nations Framework Convention on Climate Change (UNFCCC) Conference of the Parties (COP) negotiations have examined the energy implications of climate scenarios in depth. These include:

  • The World Energy Outlook 2008, which assessed two scenarios in which the atmospheric concentration of emissions stabilised at 550 parts per million (ppm) and 450 ppm respectively, to inform the design of a post-Kyoto climate framework at COP 15 in Copenhagen in 2009.
  • Redrawing the Energy-Climate Map, a World Energy Outlook special report published in 2013, that fed into COP 19 in Warsaw, setting out key measures for the energy sector to stay within the 2.0 °C target and make further reductions.
  • The World Energy Outlook 2015 Special Report on Energy and Climate Change, which contributed to preparations for COP 21 in Paris with a detailed assessment of how national climate pledges impact the energy sector.