5.3 The International Energy Agency Net Zero scenario

The global energy sector is already undergoing a transformation and starting to move away from fossil-fuel-based electricity generation. This has been achieved by a considerable expansion of renewable energy, especially solar and wind power, which in turn is largely due to a rapid fall in the costs of renewable electricity generation. The mass production of solar photovoltaic (PV) panels in China has now made the electricity from large-scale solar PV projects cheaper than fossil-fuelled electricity in many countries. Similarly, wind power development in Europe has made wind-generated electricity (both onshore and offshore) cheaper than that from fossil fuels (IPCC, 2023; IEA, 2021).

The International Energy Agency (IEA) is an intergovernmental organisation that regularly produces detailed energy statistics and economic analyses of world energy use. In their 2023 World Energy Outlook (IEA, 2023), they estimated that in 2022 over three quarters of the world’s primary energy supply came from the fossil fuels coal, oil and natural gas (see the pie chart in Figure 14). Renewable energy made up about 16% of the total.

Their report also contained a scenario for possible future world energy use aimed at limiting global temperature rise to 1.5 °C by 2100 (it assumed continuing world economic growth and a slowly increasing world population). This scenario was called ‘Net Zero Emissions by 2050’. In addition, the scenario aimed to meet two United Nations Sustainable Development Goals (SDGs) by 2030 (IEA, 2023, p. 88):

• providing access to electricity for the 775 million people in the world who lacked this in 2023
• providing access to clean cooking for the 2.2 billion people who lacked this in 2023.

The IEA modellers worked backwards from these assumptions to produce a scenario of possible future changes to the global energy economy and the necessary flows of investment. Not surprisingly, this scenario requires rapid major changes. Figure 13(a) highlights the fact that to reach net zero CO₂ emissions by 2050, global CO₂ emissions from energy would need to fall from about 37 Gt per year in 2022 to around 6 Gt in 2040, before reaching net zero in 2050. This is projected to limit global temperature rise to 1.5 °C.

Reaching the less ambitious target of 2 °C by 2100 requires the same level of cuts by 2055, rather than 2040, and net zero in 2070.

What does the IEA’s ‘Net Zero Emissions by 2050’ scenario mean in terms of global energy use? The IEA energy modellers have produced what they think is a possible world energy supply scenario by 2040, with total CO₂ emissions of only 6 Gt per year. This is shown in Figure 15.

In this energy mix, fossil fuels only make up 30% of the total. They are replaced by an enormous expansion in renewable energy sources such as solar electricity and wind power. There is also a more modest expansion of hydroelectric and nuclear power, together with the development of carbon capture, utilisation and storage (CCUS) technologies. These collect CO₂ from combustion and either bury it deep underground in layers of water-saturated rocks called aquifers or use it in other industrial processes.

The inclusion of CCUS technology and nuclear power may seem controversial and ‘un-environmental’ to some. However, achieving an equivalent cut in CO₂ emissions without using these technologies would require an even larger and more rapid expansion of wind and solar power (Teske, 2019).

If this transformation in energy supply can be achieved by 2040, then the world will indeed be on a pathway to limiting global temperature rise to 1.5 °C. If the global energy economy cannot change so quickly, then the temperature rise is likely to be greater. To limit the temperature rise to 2 °C, this low level of 6 Gt of CO₂ emissions per year needs to be reached just 15 years later, in 2055 (see Figure 16).

This shows that there is only a small window of opportunity to act – any further delay in these drastic CO₂ emission reductions could lead to a global temperature rise above 2 °C, with the risk of dangerous climate change. Each degree (and fraction of a degree) of warming is critical, as research has shown that the impacts from 2 °C of warming are highly likely to be much more severe than the impacts from 1.5 °C (IPCC, 2018).