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.
A cleaner and more inclusive energy future
The world is not on track to meet the energy-related components of the Sustainable Development Goals (SDGs). The IEA’s Sustainable Development Scenario (SDS) outlines a major transformation of the global energy system, showing how the world can change course to deliver on the three main energy-related SDGs simultaneously.
An integrated approach to energy and sustainable development
Based on existing and announced policies – as described in the IEA Stated Policies Scenario (STEPS) – the world is not on course to achieve the outcomes of the UN SDGs most closely related to energy: to achieve universal access to energy (SDG 7), to reduce the severe health impacts of air pollution (part of SDG 3) and to tackle climate change (SDG 13).
The SDS sets out an ambitious and pragmatic vision of how the global energy sector can evolve in order to achieve these critical energy-related SDGs. It starts with the SDG outcomes and then works back to set out what would be needed to deliver these goals in a realistic and cost-effective way. In the WEO-2019, the Sustainable Development Scenario is extended out to 2050 for the first time.
The SDS is fully aligned with the Paris Agreement
The Paris Agreement has an objective of “holding the increase in the global average temperature to well below 2 °C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C above pre-industrial levels”. Energy production and use is the largest source of global greenhouse-gas (GHG) emissions, meaning that the energy sector is crucial for achieving this objective.
To achieve the temperature goal, the Paris Agreement calls for emissions to peak as soon as possible and reduce rapidly thereafter, leading to a balance between anthropogenic emissions by sources and removals by sinks (i.e. net-zero emissions) in the second half of this century. These conditions are all met in the SDS.
The SDS holds the temperature rise to below 1.8 °C with a 66% probability without reliance on global net-negative CO2 emissions; this is equivalent to limiting the temperature rise to 1.65 °C with a 50% probability. Global CO2 emissions fall from 33 billion tonnes in 2018 to less than 10 billion tonnes by 2050 and are on track to net zero emissions by 2070.
Compare the new SDS 2019 to IPCC scenarios with a temperature rise in 2100
How does SDS relate to the pursuit of a 1.5°C outcome?
The IPCC Special Report on Global Warming of 1.5°C, published in 2018, assessed a large number of scenarios that led to at least a 50% chance of limiting the temperature rise to 1.5 °C. As the figure above makes clear, the SDS trajectory is well within the envelope of these scenarios.
Almost all of these IPCC scenarios (88 out of 90) assume some level of net negative emissions. The Sustainable Development Scenario does not rely on net negative emissions, but if the requisite technologies became available at scale, warming could be further limited. A level of net negative emissions significantly smaller than that used in most scenarios assessed by the IPCC would provide the Sustainable Development Scenario with a 50% probability of limiting the rise in global temperatures to 1.5°C.
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In the light of concern surrounding negative emissions technologies, it would be possible to construct a scenario that goes further than the Sustainable Development Scenario and delivers a 50% chance of limiting warming to 1.5 °C without any reliance on net-negative emissions. These conditions would require achieving net zero emissions globally by around 2050.
Eliminating the 10 Gt CO2 energy-sector emissions remaining in SDS in 2050 would not amount to a simple extension of the changes to the energy system described in the SDS. The additional changes involved – particularly those surrounding rates of technological change, infrastructure constraints, social acceptance and behavioural changes, and capital stock replacement – would pose challenges that would be very difficult and very expensive to surmount. This is not something that is within the power of the energy sector alone to deliver. Change on a massive scale would be necessary across a very broad front, and would impinge directly on the lives of almost everyone.
Universal access to modern energy is achieved by 2030 in line with SDG 7
The Paris Agreement is also clear that climate change mitigation objectives should be fulfilled in the context of sustainable development and efforts to eradicate poverty. The Sustainable Development Scenario explicitly supports these broader development efforts (in contrast to most other decarbonisation scenarios), in particular through its energy access and cleaner air dimensions.
A strong drive towards electrification (on-grid and off-grid) and provision of clean cooking facilities means the number of people without access to modern energy drops to zero by 2030, transforming the lives of hundreds of millions, and reducing the severe health impacts of indoor air pollution, overwhelmingly caused by smoke from cooking.
Sub-Saharan Africa Developing Asia Latin America North Africa Middle East Developing countries 2010 13 43 85 96 95 45 2011 13 44 86 96 95 46 2012 14 46 86 97 95 48 2013 14 48 87 97 95 49 2014 15 51 87 97 95 51 2015 15 53 88 98 96 53 2016 16 56 88 98 96 54 2017 16 57 88 98 96 55 2018 17 57 89 98 96 56 2019 24 61 90 98 96 59 2020 31 64 90 98 96 63 2021 38 68 91 98 96 66 2022 45 71 92 99 96 70 2023 51 75 93 99 96 74 2024 58 79 94 99 96 77 2025 65 82 95 99 96 81 2026 72 86 96 99 96 85 2027 79 89 97 99 96 89 2028 86 93 98 100 96 92 2029 93 96 99 100 96 96 2030 100 100 100 100 96 100
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Sub-Saharan Africa Developing Asia Latin America North Africa Middle East Developing countries 2010 33 79 94 99 91 74 2011 33 81 95 99 91 75 2012 35 82 95 99 92 76 2013 36 83 95 99 92 77 2014 38 85 96 99 92 78 2015 40 87 96 99 92 80 2016 42 88 96 100 92 81 2017 44 91 97 100 92 83 2018 45 94 97 100 93 86 2019 51 96 97 100 94 87 2020 56 97 97 100 95 89 2021 62 98 98 100 96 91 2022 68 98 98 100 97 92 2023 74 99 98 100 98 94 2024 79 99 98 100 99 95 2025 84 99 99 100 99 96 2026 88 99 99 100 99 97 2027 91 100 99 100 100 98 2028 95 100 99 100 100 99 2029 98 100 100 100 100 99 2030 100 100 100 100 100 100
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Health impacts due to energy-related air pollution are reduced dramatically
Outdoor air pollution is reduced substantially, leading to more than 1.6 million fewer premature deaths globally in 2050 than projected under current trends. Indoor air pollution also falls sharply, with access to clean cooking contributing to more than 1.5 million fewer premature deaths.
Premature deaths Premature deaths Premature deaths 2018 2.96 2050 STEPS 5.14 2050 SDS 2.97 2018 2.49 2050 STEPS 1.8 2050 SDS 0.8
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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 SDS. Achieving universal access to modern energy only leads to a small increase in CO2 emissions (0.1%), the climate effect of which is more than offset by lower methane emissions due to a reduction in use of traditional biomass cookstoves. Incorporating additional elements of the sustainable development agenda, such as energy and water, or energy and gender, highlight further synergies.
The transition to a low-carbon economy leads to a more efficient energy system that relies less on fuel combustion; this plays a major role in improving air quality, reducing both outdoor and household air pollution. In countries where reducing health impacts of air pollution is an urgent issue, low-carbon measures that reduce the overall quantity of fossil fuels being used – including energy efficiency measures on the demand side, and a shift to renewables on the supply side – are an important part of an action plan to tackle those health-related impacts.
Investment
The SDS requires around an increase in overall investment compared to STEPS of around 25% over the period to 2050. This additional investment cost is partially counterbalanced by reduced fuel costs, which mitigates the impact on the energy bills paid by consumers. There is a significant shift in capital spending away from fossil fuels to renewables and other low-carbon sources as well as to electricity (Figure 2.10).
The largest increase in supply investment comes from renewables-based power, which is on average double today’s level between 2019 and 2050. This is supported by additional spending on electricity grids and battery storage, in order to ensure reliable electricity supply.
The other major shift in spending is towards the demand side, to take advantage of the huge potential for energy efficiency. This means additional spending on more efficient buildings, industrial processes and transport, as well as new demand-side infrastructure, e.g. for EV recharging.
The investment needed to achieve universal energy access amounts to some $45 billion per year between 2019 and 2030, the lion’s share of it for electricity access. While this is more than double the amount in the Stated Policies Scenario, it is less than 2% of the total annual energy sector investment in the Sustainable Development Scenario.
Oil Natural gas Coal Biofuels 2014-18 0.528 0.299 0.098 0.005 2019-50 0.281 0.24 0.018 0.033
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Fossil fuels (w/o CCUS) Fossil fuels (w/CCUS) Nuclear Renewables Networks Battery storage 2014-18 0.137 0.001 0.041 0.303 0.291 0.002 2019-50 0.039 0.024 0.067 0.607 0.575 0.037
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Renewables Efficiency Other 2014-18 0.08 0.238 0.047 2019-50 0.149 0.825 0.664
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A decade of WEO energy transition scenarios; how is the new SDS different?
The World Energy Outlook introduced a detailed energy transition scenario in 2009 – then called the 450 Scenario. The scenario got its name from 450 parts per million (ppm), the CO2 concentration that was seen at that time to be consistent with a 50% likelihood of keeping average global temperature rise below 2 °C (assuming that net zero emissions were reached in 2100).
Since then the global goalposts have shifted, technological progress has been uneven, and emissions have continued to grow. The SDS looks very different from the 450 Scenario proposed in the WEO-2009, for three main reasons:
- A tougher starting point. Energy-related CO2 emissions in 2018 reached a record high of 33 billion tonnes (Gt) - a huge 2.5 Gt above the level what was set out in the 450 Scenario for 2018. Not only does this mean that emissions in the SDS must fall to a greater extent than in the 450 Scenario, but there is also a larger carbon-intensive capital stock that must be managed.
- Higher ambition. The 450 Scenario was compatible with reaching net-zero CO2 emissions towards the end of the century whereas SDS aims to achieve net-zero CO2 emissions in 2070. The emissions trajectory of SDS, combined with the higher starting point, means that emissions decline by 730 million tonnes (Mt) on average each year compared with a 400 Mt average annual decline in the 450 Scenario.
- Uneven technological progress. The SDS relies much more on solar and wind in the power sector, and less on carbon capture, utilisation and storage (CCUS) and nuclear than the 450 Scenario. For example, in 2030 in the 450 Scenario from the WEO-2009, nuclear and CCUS generated around 7 100 TWh of electricity while wind and solar PV generated 3 600 TWh. In the SDS these figures are broadly reversed with nuclear and CCUS generating 3 900 TWh, and wind and solar PV generating 8 100 TWh.