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

==== 4.2.5.5 Nuclear Power Is Considered Strategic for Some Countries, While Others Plan to Reach Their Mitigation Targets Without Additional Nuclear Power ====

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Nuclear power generation is developed in many countries, though larger-scale national nuclear generation does not tend to associate with significantly lower carbon emissions ( [[#Sovacool--2020|Sovacool et al. 2020]] ). Unlike other energy sources such as wind and PV solar, levelised costs of nuclear power has been rising in the last decades ( [[#Grubler--2010|Grubler 2010]] ; [[#Gilbert--2017|Gilbert et al. 2017]] ; [[#Portugal-Pereira--2018|Portugal-Pereira et al. 2018]] ). This is mainly due to overrun of overnight construction costs related to delays in project approvals and construction, and more stringent passive safety measures, which increases the complexity of systems. After the Fukushima Daiichi accident in Japan, nuclear programs in several countries have been phased out or cancelled ( [[#Carrara--2020|Carrara 2020]] ; [[#Huenteler--2012|Huenteler et al. 2012]] ; [[#Kharecha--2019|Kharecha and Sato 2019]] ; [[#Hoffman--2018|Hoffman and Durlak 2018]] ). Also the compatibility of conventional prresurised water reactors and boiling water reactors with large proportion of renewable energy in the grid it is yet to be fully understood.

Accelerated mitigation scenarios offer contrasting views on the share of nuclear in power generation. In the USA, ( [[#Victor--2018|Victor et al. 2018]] ) build a scenario in which nuclear contributes 23% of CO 2 emission reductions needed to reduce GHG emissions by 80% from 2005 levels by 2050. Deep power sector decarbonisation pathways could require a two-folded increase in nuclear capacity according to ( [[#Jayadev--2020|Jayadev et al. 2020]] ) for the USA, and nearly a ten-fold increase for Canada, but may be difficult to implement ( [[#Vaillancourt--2017|Vaillancourt et al. 2017]] ). For China to meet a 1.5°C pathway or achieve carbon neutrality by 2050, nuclear may represent 14–28% of power generation in 2050 according to ( [[#Jiang--2018|Jiang et al. 2018]] ; [[#China%20National%20Renewable%20Energy%20Centre--2019|China National Renewable Energy Centre 2019]] ; [[#Energy%20Transitions%20Commission%20and%20Rocky%20Mountain%20Institute--2019|Energy Transitions Commission and Rocky Mountain Institute 2019]] ). For South Korea, [[#Hong--2014|Hong et al. (2014)]] and [[#Hong--2018|Hong and Brook (2018)]] find that increasing nuclear power can help complement renewables in decarbonising the grid. Similarly, India has put in place a three-stage nuclear programme which aims to enhance nuclear power capacity from the current level of 6 GW to 63 GW by 2032, if fuel supply is ensured (GoI 2015). Nuclear energy is also considered necessary as part of accelerated mitigation pathways in Brazil, although it is not expected to increase significantly by 2050 even under stringent low-carbon scenarios ( [[#Lucena--2016|Lucena et al. 2016]] ). France developed its nuclear strategy in response to energy security concerns after the 1970s oil crisis, but has committed to reducing nuclear’s share of power generation to 50% by 2035 ( [[#Millot--2020|Millot et al. 2020]] ). Conversely, some analysis find deep mitigation pathways, including net zero GHG emissions and 80–90% reduction from 2013 levels, feasible without additional nuclear power in EU-28 and Japan respectively, but assuming a combination of bio- and novel fuels and CCS or land-use based carbon sinks ( [[#Kato--2019|Kato and Kurosawa 2019]] ; [[#Duscha--2019|Duscha et al. 2019]] ).

Radically more efficient use of energy than today, including electricity, is a complementary set of measures, explored in the following.

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