Editing IPCC:AR6/WGIII/Chapter-17 (section)

==== 17.3.2.2 Renewable Energy Penetration and Fossil Fuel Phase-o ut ====

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As pointed out in Chapter 6, the achievement of long-term temperature goals in line with the Paris Agreement requires the rapid penetration of renewable energy and a timely phasing out of fossil fuels, especially coal, from the global energy system. Limiting warming to 1.5°C (&gt;50%) with no or limited overshoot means that global CO 2 emissions must reach ‘net zero’ in 2050/2060 ( [[#IPCC--2018|IPCC 2018]] ). Net zero emissions imply that fossil fuel use is minimised and replaced by renewables and other low-carbon primary forms of energy, or that the residual emissions from fossil fuels are offset by carbon dioxide removal (CDR). The 1.5°C scenario requires a 2–3% annual improvement rate in carbon intensities till 2050. The historical record only shows a slight improvement in the carbon intensity rate of global energy supplies, far from what is required to limit global warming to 2°C (&gt;67%), or limit warming to 1.5°C (&gt;50%) with no or limited overshoot.

The role of coal in the global energy system is changing fast. Given the global temperature goals of the Paris Agreement, the global coal sector needs a transition to near zero by 2050 – earlier in some regions ( [[#Bauer--2018|Bauer et al. 2018]] ; [[#IEA--2017|IEA 2017]] ; [[#IPCC--2018|IPCC 2018]] ). Other global trends, including air quality, water shortages, the improved cost efficiencies of renewables, the technical availability of energy storage and the economic rebalancing of emerging countries, are also driving global coal consumption to a plateau followed by a reverse ( [[#Sator--2018|Sator 2018]] ; [[#Spencer--2018|Spencer et al. 2018]] ). The world should be prepared for a managed transition away from coal and should identify appropriate transition options for the future of coal, which can include both the penetration of renewable energy and improvements in energy efficiency ( [[#Shah--2015|Shah et al. 2015]] ).

Phasing out fossil fuels from energy systems is technically possible and is estimated to be relatively low in cost (Chapter 6). The cost of low-carbon alternatives, including onshore and offshore wind, solar photovoltaic (PV) and electric vehicles, has been reduced substantially in recent years and has become competitive with fossil fuels ( [[#Shen--2020|Shen et al. 2020]] ). However, studies show that replacing fossil fuels with renewables can have major synergies and trade-offs with a broader agenda of sustainable development ( [[#Swain--2020|Swain and Karimu 2020]] ), including land use and food security ( [[#McCollum--2018|McCollum et al. 2018]] ), decent jobs and economic growth ( [[#Swain--2020|Swain and Karimu 2020]] ). Clarke et al. (AR5 WG III Table 6.7) provides detailed mapping of the sectoral co-benefits and adverse side-impacts of and links to transformation pathways. In [[#17.3.3.7|Section 17.3.3.7]] , this is supplemented with a mapping of the synergies and trade-offs between the deployment of renewable energy and the SDGs.

The general conclusion is that the potential co-benefits of renewable-energy end-use measures outweigh the adverse impacts in most sectors and in relation to the SDGs, though this is not the case for the AFOLU (agriculture, forestry and other land use) sectors. Some locally negative economic impacts can result in increased energy costs and competition over land areas and water resources. Some sectors may also experience increasing unemployment as a consequence of the transition process. Although the deployment of renewable energy will generate a new industry and associated jobs and benefits in some areas and economies, these impacts will often not directly replace or offset activities in areas that have been heavily dependent on the fossil fuel industry.

The transition to low-emission pathways will require policy efforts that also address the emissions that are locked-in to existing infrastructure such as power plants, factories, cargo ships and other infrastructure already in use: for example, today coal-fired power plants account for 30% of all energy-related emissions ( [[#IEA--2019|IEA 2019]] ). Over the past twenty years, Asia has accounted for 90% of all coal-fired capacity built worldwide, and these plants have potentially long operational lifetimes ahead of them. In developing economies in Asia, existing coal-fired plants are just twelve years old on average. There are three options for bringing down emissions from the existing stock of plants: to retrofit them with carbon capture and storage (CCS) or biomass co-firing equipment; to repurpose them to focus on providing system adequacy and flexibility while reducing operations; and to retire them early. In the IEA Sustainable Development Scenario, most of the 2080 GW of existing coal-fired capacity would be affected by one of these three options.

Even though the transition away from fossil fuels is desirable and technically feasible, it is still largely constrained by existing fossil fuel-based infrastructure and stranded investments. The ‘committed’ emissions from existing fossil fuel infrastructure may consume all the remaining carbon budget in the 1.5°C scenario, or two thirds of the carbon budget in the 2°C scenario ( [[#Tong--2019|Tong et al. 2019]] ). ( [[#Kefford--2018|Kefford et al. 2018]] ) assess the early retirement of fossil fuel power plants in the US, EU, China and India based on the IEA 2°C scenario and

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