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

==== 6.6.2.3 Widespread Electrification of End Uses ====

<div id="h3-26-siblings" class="h3-siblings"></div>

Net-zero energy systems will rely more heavily on increased use of electricity (electrification) in end uses ( ''high confidence'' ). The literature on net-zero energy systems almost universally calls for increased electrification ( [[#Sugiyama--2012|Sugiyama 2012]] ; [[#Williams--2012|Williams et al. 2012]] ; [[#Kriegler--2014a|Kriegler et al. 2014a]] ; [[#Williams--2014|Williams et al. 2014]] ; [[#Rogelj--2015a|Rogelj et al. 2015a]] ; [[#Sachs--2016|Sachs et al. 2016]] ; [[#Luderer--2018|Luderer et al. 2018]] ; [[#Sven--2018|Sven et al. 2018]] ; [[#Schreyer--2020|Schreyer et al. 2020]] ). At least 30% of the global final energy needs are expected to be served by electricity, with some estimates suggesting upwards of 80% of total energy use being electrified (Figure 6.22, panel c). Increased electrification is especially valuable in net-zero energy systems in tandem with decarbonised electricity generation or net-negative emissions electricity generation ( [[#6.5.4|Section 6.5.4]] .2). Flexible electric loads (electric vehicles, smart appliances) can in turn facilitate incorporation of VRE electricity options, increase system flexibility, and reduce needs for grid storage ( [[#6.4.3|Section 6.4.3]] ) ( [[#Mathiesen--2015|Mathiesen et al. 2015]] ; Lund et al. 2018).

Several end uses, such as passenger transportation (light-duty electric vehicles, two and three wheelers, buses, rail) as well as building energy uses (lighting, cooling) are likely to be electrified in net-zero energy systems ( ''high confidence'' ). Variations in projections of electrification largely result from differences in expectations about the ability and cost-competitiveness of electricity to serve other end uses such as non-rail freight transport, aviation, and heavy industry ( [[#McCollum--2014|McCollum et al. 2014]] ; [[#Bataille--2016|Bataille et al. 2016]] ; [[#EPRI--2018|EPRI 2018]] ; [[#Breyer--2019|Breyer et al. 2019]] ) ( [[#6.5.4|Section 6.5.4]] .4), especially relative to biofuels and hydrogen (‘low-carbon fuels’) ( [[#McCollum--2014|McCollum et al. 2014]] ; [[#Sachs--2016|Sachs et al. 2016]] ; [[#Rockström--2017|Rockström et al. 2017]] ), the prospects for which are still quite uncertain ( [[#6.4|Section 6.4]] ). The emergence of CDR technologies and the extent to which they allow for residual emissions as an alternative to electrification will also affect the overall share of energy served by electricity ( [[#6.6.2.7|Section 6.6.2.7]] ).

Regions endowed with cheap and plentiful low-carbon electricity resources (wind, solar, hydropower) are likely to emphasise electrification, while those with substantial bioenergy resources or availability of other liquid fuels might put less emphasis on electrification, particularly in hard-to-electrify end uses ( ''medium confidence'' ). For example, among a group of Latin American countries, relative assumptions about liquid fuels and electricity result in an electrification range of 28–82% for achieving a net-zero energy system ( [[#Bataille--2020|Bataille et al. 2020]] ). Similarly, the level of penetration of biofuels that can substitute for electrification will depend on regional circumstances such as land-use constraints, competition with food, and sustainability of biomass production ( [[#6.6.2.4|Section 6.6.2.4]] ).

Electrification of most buildings services, with the possible exception of space heating in extreme climates, is expected in net-zero energy systems ( ''high confidence'' ) (Chapter 9). Space cooling and water heating are expected to be largely electrified. Building electrification is expected to rely substantially on heat pumps, which will help lower emissions both through reduced thermal requirements and higher efficiencies ( [[#Mathiesen--2015|Mathiesen et al. 2015]] ; [[#Sven--2018|Sven et al. 2018]] ; [[#Rissman--2020|Rissman et al. 2020]] ). The level of electrification for heating will depend on the trade-offs between building or household level heat pumps versus more centralised district heating network options ( [[#Mathiesen--2015|Mathiesen et al. 2015]] ; [[#Brown--2018|Brown et al. 2018]] ), as well as the cost and performance of heat pumps in more extreme climates and regional grid infrastructure ( [[#EPRI--2018|EPRI 2018]] ; [[#Waite--2020|Waite and Modi 2020]] ).

A significant share of transportation, especially road transportation, is expected to be electrified in net-zero energy systems ( ''high confidence'' ). In road transportation, two- and three-wheelers, light-duty vehicles (LDVs), and buses, are especially amenable to electrification, with more than half of passenger LDVs expected to be electrified globally in net-zero energy systems ( ''medium confidence'' ) ( [[#Fulton--2015|Fulton et al. 2015]] ; [[#Sven--2018|Sven et al. 2018]] ; [[#Khalili--2019|Khalili et al. 2019]] ; [[#Bataille--2020|Bataille et al. 2020]] ). Long-haul trucks, large ships, and aircraft are expected to be harder to electrify without technological breakthroughs ( [[#Fulton--2015|Fulton et al. 2015]] ; [[#Mathiesen--2015|Mathiesen et al. 2015]] ), although continued improvements in battery technology may enable electrification of long-haul trucks ( [[#Nykvist--2021|Nykvist and Olsson 2021]] ) (Chapter 10). Due to the relative ease of rail electrification, near complete electrification of rail and a shift of air and truck freight to rail is expected in net-zero energy systems ( [[#Fulton--2015|Fulton et al. 2015]] ; [[#Rockström--2017|Rockström et al. 2017]] ; [[#Sven--2018|Sven et al. 2018]] ; [[#Khalili--2019|Khalili et al. 2019]] ). The degree of modal shifts and electrification will depend on local factors such as infrastructure availability and location accessibility. Due to the challenges associated with electrification of some transport modes, net-zero energy systems may include some residual emissions associated with the freight sector that are offset through CDR technologies ( [[#Muratori--2017b|Muratori et al. 2017b]] ), or reliance on low and zero-carbon fuels instead of electrification.

A non-trivial number of industry applications could be electrified as a part of a net-zero energy system, but direct electrification of heavy industry applications such as cement, primary steel manufacturing, and chemical feedstocks is expected to be challenging ( ''medium confidence'' ) ( [[#Davis--2018|Davis et al. 2018]] ; [[#Philibert--2019|Philibert 2019]] ; [[#Madeddu--2020|Madeddu et al. 2020]] ; van Sluisveld et al. 2021). Process and boiler heating in industrial facilities are anticipated to be electrified in net-zero energy systems. Emissions intensity reductions for cement and concrete production can be achieved through the use of electrified cement kilns, while emissions associated with steel production can be reduced through the use of an electric arc furnace (EAF) powered by decarbonised electricity ( [[#Rissman--2020|Rissman et al. 2020]] ). Electricity can also be used to replace thermalheat such as resistive heating, EAFs, and laser sintering ( [[#Madeddu--2020|Madeddu et al. 2020]] ; [[#Rissman--2020|Rissman et al. 2020]] ). One study found that as much as 60% of the energy end-use in European industry could be met with direct electrification using existing and emerging technologies ( [[#Madeddu--2020|Madeddu et al. 2020]] ). Industry electrification for different regions will depend on the economics and availability of alternative emissions mitigation strategies such as carbon neutral fuels and CCS ( [[#Davis--2018|Davis et al. 2018]] ; [[#Madeddu--2020|Madeddu et al. 2020]] ).

<div id="6.6.2.4" class="h3-container"></div>

<span id="alternative-fuels-in-sectors-not-amenable-to-electrification"></span>