Editing IPCC:AR6/WGIII/Chapter-6 (section)

==== 6.6.2.1 Limited and/or Targeted Use of Fossil Fuels ====

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Net-zero energy systems will use far less fossil fuel than today ( ''high confidence'' ). The precise quantity of fossil fuels will largely depend on the relative costs of such fuels, electrification, alternative fuels, and CDR ( [[#6.6.2.4|Section 6.6.2.4]] ) in the energy system ( ''high confidence'' ). All of these are affected by regional differences in resources ( [[#McGlade--2015|McGlade and Ekins 2015]] ), existing energy infrastructure ( [[#Tong--2019|Tong et al. 2019]] ), demand for energy services, and climate and energy policies. Fossil fuel use may persist, for example, if and where the costs of such fuels and the compensating carbon management (e.g., CDR, CCS) are less than non-fossil energy. For most applications, however, it is likely that electrification ( [[#McCollum--2014|McCollum et al. 2014]] ; [[#Madeddu--2020|Madeddu et al. 2020]] ; [[#Zhang--2020|Zhang and Fujimori 2020]] ) or use of non-fossil alternative fuels ( [[#Zeman--2008|Zeman and Keith 2008]] ; [[#Graves--2011|Graves et al. 2011]] ; [[#Hänggi--2019|Hänggi et al. 2019]] ; [[#Ueckerdt--2021|Ueckerdt et al. 2021]] ) will prove to be the cheapest options. Most residual demand for fossil fuels is likely to predominantly be petroleum and natural gas given their high energy density ( [[#Davis--2018|Davis et al. 2018]] ), while demand for coal in net-zero energy systems is likely to be very low ( [[#Luderer--2018|Luderer et al. 2018]] ; [[#Jakob--2020|Jakob et al. 2020]] , [[#6.7.4|Section 6.7.4]] ) ( ''high confidence'' ).

There is considerable flexibility regarding the overall quantity of liquid and gaseous fuels that will be required in net-zero energy systems ( ''high confidence'' ) (Figure 6.22 and [[#6.7.4|Section 6.7.4]] ). This will be determined by the relative value of such fuels as compared to systems which rely more or less heavily on zero-emissions electricity. In turn, the share of any fuels that are fossil or fossil-derived is uncertain and will depend on the feasibility of CCS and CDR technologies and long-term sequestration as compared to alternative, carbon-neutral fuels. Moreover, to the extent that physical, biological, and/or socio-political factors limit the availability of CDR ( [[#Smith--2015|Smith et al. 2015]] ; [[#Field--2017|Field and Mach 2017]] ), carbon management efforts may prioritise residual emissions related to land use and other non-energy sources.

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