World Energy Model

Scenario analysis of future energy trends

Since 1993, the IEA has provided medium to long-term energy projections using the World Energy Model (WEM) – a large-scale simulation model designed to replicate how energy markets function. The WEM is the principal tool used to generate detailed sector-by-sector and region-by-region projections for the WEO scenarios. Download the WEM Methodology document for an in depth description of the overall approach and features of the model.

Scenarios in WEO 2019

The World Energy Outlook does not provide a forecast of what will happen. Instead, it provides a set of scenarios that explore different possible futures, the actions – or inactions – that bring them about and the interconnections between different parts of the system.

Stated Policies Scenario (STEPS)

The Stated Policies Scenario, or STEPS, which identical in design to the previous New Policies Scenario, provides a detailed sense of the direction in which today’s policy ambitions would take the energy sector. Previously known as the New Policies Scenario, it has been renamed to underline that it considers only specific policy initiatives that have already been announced.

Learn more about STEPS

Sustainable Development Scenario (SDS)

The Sustainable Development Scenario (SDS) maps out a way to meet sustainable energy goals in full, requiring rapid and widespread changes across all parts of the energy system. This scenario charts a path fully aligned with the Paris Agreement by holding the rise in global temperatures to “well below 2°C … and pursuing efforts to limit [it] to 1.5°C”, and meets objectives related to universal energy access and cleaner air.

Learn more about the SDS

Current Policies Scenario (CPS)

The Current Policies Scenario is a baseline picture of how global energy markets would evolve if governments make no changes to their existing policies and measures.

Africa Case (AC)

A new Africa Case AC was developed for the Special Focus on Africa in WEO 2019 that reflects the Agenda 2063, in which African leaders set out their vision for the future growth and development of the continent.


Previous WEO scenarios

Future is Electric Scenario

This is a scenario developed specifically for the WEO 2018 special focus on electrification. It starts from the conditions of the New Policies Scenario and explores key areas of uncertainty for future electricity demand. A range of electric technologies are widely taken up as soon as they become cost-competitive.

Faster Transition Scenario

This scenario, developed in 2017, plots an emissions pathway to "net zero" energy sector CO2 emissions in 2060, resulting in lower emissions than the SDS in 2040.

Low Oil Price Case

This case, considered in Chapter 4 of WEO 2017, looks at the conditions that would allow the oil price to remain "lower for longer". It updates the Low Oil Price Scenario presented in WEO 2015.

Energy for All Case

Developed specifically for 2017, this case examines the achievement of modern energy for all against the backdrop of the STEPS. It provides a point of comparison with the way that a similar goal is covered in the SDS.

450 Scenario

In this scenario, policies are adopted that put the world on a pathway that is consistent with having around a 50% chance of limiting the global increase in average temperature to 2°C in the long term, compared with pre-industrial levels.

Clean Air Scenario

Introduced in a WEO special report in 2016, this scenario set out a cost-effective strategy, based on existing technologies and proven policies, to cut 2040 pollutant emissions by more than half compared with the STEPS.

Bridge Scenario

Featured in another WEO special report in 2015, this scenario put forward a bridging strategy, based on five specific energy sector measures, to achieve an early peak in energy-related CO2 emissions.

The 4-for-2 Scenario

This scenario was developed with a view on short-term climate mitigation options until 2020. The short-term measures considered in this scenario go beyond policies already adopted and entail measures that require either significant further strengthening and wider adoption, or that are currently not high on the policy agenda, even though the measures required to implement the relevant policies are known and their adoption could make a significant additional difference.

Emissions of Air Pollutants

This report, prepared by IISA, examines global emissions of major air pollutants (SO2, NOx, PM2.5) resulting from energy scenarios developed for the WEO 2012, which have been estimated using the IIASA GAINS model. The Scenario labelled High Energy Efficiency Scenario corresponds to the Efficient World Scenario in WEO 2012.

Emissions of Air Pollutants in India

This report prepared by IIASA examines emissions of major air pollutants (SO2, NOx, PM2.5) for India resulting from energy scenarios developed for the WEO 2015, which have been estimated using the IIASA GAINS model.

Efficient World Scenario

In this scenario, all energy-efficiency investments that are economically viable are made and all necessary policies to eliminate market barriers to energy efficiency are adopted.