Environment & Energy

7.3 Energy pathways in the NZE Scenario

The NZE Scenario illustrates a possible global path to the goal of net zero emissions by 2050. Each country will have its own pathway, depending on their circumstances. The energy transition set out in the NZE Scenario has four main pillars: deployment of low-emissions sources of electricity and electrification to reduce emissions in end-uses; improvements in energy efficiency; use of low-emissions fuels such as hydrogen, biofuels, and CCUS; and reductions in methane emissions. These strategies rapidly reduce emissions and drive a demand-led transition away from fossil fuels in this scenario.

7.3.1 Clean electrification

Today, the power sector accounts for about 40% of global energy-related emissions. Shifting electricity generation to low-emissions sources and increasing the deployment of lowemissions electricity in existing and new end-uses are central to the NZE Scenario: these strategies give rise to around two-thirds of the emissions reductions to 2035 (Figure 7.12). In the NZE Scenario, low-emissions sources provide nearly all electricity generation by 2040, while electricity increases its share in total final consumption to around 40% by 2040 and 55% by 2050. The expanding role of electricity in total final consumption and the increase in electricity supply from variable renewable sources underline the importance of electricity security in the NZE Scenario.


Generating electricity with low-emissions sources

Low-emissions sources of electricity – renewables, nuclear, fossil fuels with CCUS, hydrogen and ammonia – accounted for just over 40% of global electricity generation in 2024, up from around 30% a decade ago. Renewables were responsible for 32% of power generation worldwide, and nuclear for around 9%: there was also a very small contribution of less than 0.003% from fossil fuels equipped with CCUS.

Global installed capacity of renewables triples to 2030 from a 2022 baseline in the NZE Scenario, building on the strong momentum already seen in the power sector, and meeting the goal set at COP28 in 2023 (Figure 7.13). As a result, renewables expand from around one-third of total generation today to around three-quarters by 2035. Achieving this while maintaining electricity security means ensuring that investment in electricity system flexibility keeps pace. Having surged by over 80% in 2024, the installed capacity of stationary batteries increases 17-fold to 2035, average of 30% per year, reaching almost 2 900 gigawatts (GW) in capacity terms and more than 8 400 gigawatt-hours (GWh) in energy terms. In the NZE Scenario, investment surges in grid infrastructure, and around 30 million kilometres (km) of new transmission and distribution lines are added by 2035.

As variable renewables such as solar PV and wind account for a rising share of generation, dispatchable capacity plays a critical role to ensure electricity security. Long lead-times for nuclear limits its role in the near term, but installed nuclear capacity in the NZE Scenario increases 70% by 2035 from the current level, and by 2050 it is two-and-a-half times higher. By the 2030s, the nuclear industry delivers annual additions of around 40 GW per year (Box 7.3). Hydropower capacity also expands strongly, with generation increasing more than 1.5-times by 2050. Unabated fossil fuel plants are operated increasingly for flexibility and capacity adequacy, and consequently their installed capacity falls more slowly than their output across the Outlook period. Fossil fuel plants equipped with CCUS and plants fired with hydrogen or ammonia are also deployed, providing additional low-emissions dispatchable capacity.