Editing IPCC:AR6/WGIII/Chapter-4 (section)

==== 4.2.5.2 Accelerated Decarbonisation of Electricity Through Renewable Energy ====

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Power generation could decarbonise much faster with scaled up deployment of renewable energy and storage. Both technologies are mature, available, and fast decreasing in costs, more than for many other mitigation options. Models continuously underestimate the speed at which renewables and storage expand. Higher penetration of renewable energy in the power sector is a common theme in scenarios. Some studies provide cost optimal electricity mix under emission constraints, while others explicitly explore a 100% renewables or 100% emission free electricity sector (Box 4.3).

Figure 4.3 shows an increasing share of renewable electricity in most countries historically, with further increases projected in many decarbonisation pathways. Targets for very high shares of renewable electricity generation – up to 100% – are shown for a number of countries, with the global share projected to range from 60% to 70% for 1.5°C with no overshoot (C0) to below 2°C (C4) scenarios. Countries and states that have set 100% renewables targets include Scotland for 2020 ( [[#Scottish%20Government--2021|Scottish Government 2021]] ), Austria (2030), Denmark (2035) and California (2045) (Figure 4.3).

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'''Figure 4.3 | Historical and projected levels and targets for the share of renewables in electricity generation.''' Sources: IEA energy balances for past trends, IPCC AR6 scenario dataset including national model and regional versions in global models (10th to 90th percentile of 1.5°C with no overshoot (C0) to below 2°C (C4) scenarios), national/regional sources.

While 100% renewable electricity generation by 2050 is found to be feasible, it is not without issues. For example, ( [[#Jacobson--2017|Jacobson et al. 2017]] , 2019) find it feasible for 143 countries with only a 9% average increase in economic costs (considering all social costs) if annual electricity demand can be reduced by 57%. Others state that challenges exist with speed of expansion, ensuring sufficient supply at all times or higher costs compared to other alternatives ( [[#Clack--2017|Clack et al. 2017]] ). In-depth discussion of net zero electricity systems can be found in [[IPCC:Wg3:Chapter:Chapter-6#6.6|Section 6.6]] .

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