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

== 6.5 Climate Change Impacts on the Energy System ==

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=== 6.5.1 Climate Impacts on the Energy System ===

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Many components of the energy system are affected by individual weather events and climate conditions (Table 6.10). In addition, a range of compounding effects can be anticipated, as the complex, interconnected climate and energy systems are influenced by multiple weather and climate conditions. This raises the question of whether the energy system transformation needed to limit warming will be impacted by climate change.

The impacts of ''climate change'' on the energy system can be divided into three areas: impacts on the energy supply; impacts on energy consumption; and impacts on energy infrastructure. The rest of this section focuses on how the ''future'' ''changes'' in climate drivers might affect the ability of the energy system transformation needed to mitigate climate change. The discussion of energy infrastructure in this section is limited to electricity system vulnerability.

'''Table 6.10 | Relevance of the key climatic impact drivers (and their respective changes in intensity, frequency, duration, timing, and spatial extent) for major categories of activities in the energy sector.''' The climate impact drivers (CIDs) are identified in Table 12.1 in [[IPCC:Wg3:Chapter:Chapter-12|Chapter 12]] of WGI AR6 report. The relevance is assessed as: positive/negative (+ or –), or both (±). D&amp;O: Design and Operation; CF: Capacity Factor.

[[File:30fe5655f0d261dba60298b17dc25953 IPCC_AR6_WGIII_Table_6_10.png]]
Relevance of the climate impact driver:

'''Figure 6.22: Characteristics of global net-zero energy systems when global energy and industrial CO''' 2 '''emissions reach net-zero.''' Scenarios reaching net-zero emissions show differences in residual emissions and carbon removal '''(a)''' , energy resources '''(b)''' , electrification '''(c)''' , energy intensity (as measured here by energy GDP –1 ) '''(d)''' , and emissions trajectory '''(e)''' , particularly with respect to warming levels (light blue = scenarios that limit warming to 1.5°C (&gt;50%) with no or limited overshoot and scenarios that return warming to 1.5°C (&gt;50%) after a high overshoot; yellow = scenarios that limit warming to 2°C (&gt;67%) and scenarios that limit warming to 2°C (&gt;50%); dark blue = scenarios that limit warming to 2.5°C (&gt;50%), scenarios that limit warming to 3°C (&gt;50%), scenarios that limit warming to 4°C (&gt;50%), and scenarios that exceed warming of 4°C (≥50%); grey = unspecified warming). Points represent individual scenarios from the AR6 Scenarios Database, with probability density distributions shown along each axis for each warming level (colours corresponding to warming levels) and for all scenarios (black).

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=== 6.5.2 Impacts on Energy Supply ===

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The increased weather dependency of future low-carbon electricity systems amplifies the possible impacts of climate change ( [[#Staffell--2018|Staffell and Pfenninger 2018]] ). However, ''globally'' climate change impacts on electricity generation – including hydro, wind and solar power potentials – should not compromise climate mitigation strategies ( ''high confidence'' ). Many of the changes in the climate system will be geographically complex at the regional and local levels. Thus, ''regionally'' climate change impacts on electricity generation could be significant. Climate change impacts on bioenergy potentials are more uncertain because of uncertainties associated with the crop response to climate change, future water availability and crop deployment. Climate change can reduce the efficiency of thermal power generation and increase the risk of power plant shutdowns during droughts. The potential additional cooling water needs of CCS can increase these risks.

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==== 6.5.2.1 dropower ====

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The impacts of climate change on hydropower will vary by region. High latitudes in the northern hemisphere are anticipated to experience increased runoff and hydropower potential. For other regions, studies find both increasing and decreasing runoff and hydropower potential. Areas with decreased runoff are anticipated to experience reduced hydropower production and increased water conflict among different economic activities ( ''high confidence'' ).

Hydropower production is directly related to the availability of water. Changes in runoff and its seasonality and changes in temperature and precipitation intensity will influence hydroelectricity production ( [[#IHA--2019|IHA 2019]] ). In general, increased precipitation will increase water availability and hydropower production. Increased precipitation intensity, however, may impact on the integrity of dam structures and affect power production by increasing debris accumulation and vegetation growth. Additionally, increased precipitation intensity results in the silting of the reservoirs or increases the amount of water spilt, resulting in erosion ( [[#Schaeffer--2012|Schaeffer et al. 2012]] ; [[#IHA--2019|IHA 2019]] ). Climate change will likely lead to higher air temperatures, resulting in more surface evaporation, less water storage, and loss of equipment efficiency ( [[#Ebinger--2011|Ebinger and Vergara 2011]] ; [[#Mukheibir--2013|Mukheibir 2013]] ; [[#Fluixá-Sanmartín--2018|Fluixá-Sanmartín et al. 2018]] ; [[#Hock--2019|Hock et al. 2019]] ). Climate change may alter the demands for water use by other sectors that often rely on stored water in multi-purpose reservoirs, and may therefore generate conflicts over water use. The increased need for water for irrigation and/or industry can affect the availability of water for hydropower generation ( [[#Spalding-Fecher--2016|Spalding-Fecher et al. 2016]] ; [[#Solaun--2017|Solaun and Cerdá 2017]] ). Higher temperatures increase glacier melt, increasing water availability for hydropower while the glaciers exist. Changes in the timing of snow and ice melt may require upgrading in storage capacity and adaptation of the hydropower plant management for fully exploiting the increase in water availability.

The conclusions regarding climate change impacts on hydropower vary due to differences in modelling assumptions and methodology, such as choice of the climate and hydrological models, choice of metrics (e.g., projected production vs hydropower potential), level of modelling details between local and global studies, reservoir operation assumptions. Also important is how hydropower production matches up with other reservoir purposes, accounting for other water and energy users, and how the competing uses are impacted by climate change ( [[#van%20Vliet--2016b|van Vliet et al. 2016b]] ; [[#Turner--2017|Turner et al. 2017]] ). Nonetheless, analyses consistently demonstrate that the global impact of climate change on hydropower will be small, but the regional impacts will be larger, and will be both positive and negative (Figure 6.20). Gross global hydropower potential in the 2050s has been estimated to slightlydecrease ( [[#Hamududu--2012|Hamududu and Killingtveit 2012]] ) between 0.4% (for the low-emission scenario) and 6.1% (for the highest-emission scenario) for the 2080s compared to 1971–2000 ( [[#van%20Vliet--2016a|van Vliet et al. 2016a]] ).

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[[File:d638a221224162ded9f7674d2feb6ef8 IPCC_AR6_WGIII_Figure_6_20.png]]

'''Figure 6.20 | Global spatial patterns of changes in gross hydropower potential based on climate forcing from five climate models.''' Changes are shown for the 2050s (upper) and the 2080s (lower) for the low-emission scenario (RCP2.6; left) and highest emission scenario (RCP8.5; right) scenarios relative to the control period (1971–2000). Source: data from [[#van%20Vliet--2016b|van Vliet et al. (2016b)]] .

Regional changes in hydropower are estimated from 5–20% increases for most areas in high latitudes ( [[#van%20Vliet--2016b|van Vliet et al. 2016b]] ; [[#Turner--2017|Turner et al. 2017]] ) to decreases of 5–20% in areas with increased drought conditions ( [[#Cronin--2018|Cronin et al. 2018]] ). Models show a consistent increase in streamflow and hydropower production by 2080 in high latitudes of the northern hemisphere and parts of the tropics (Figure 6.20) (e.g., central Africa and southern Asia) while decreasing in the USA, southern and central Europe, Southeast Asia and southern South America, Africa and Australia ( [[#van%20Vliet--2016c|van Vliet et al. 2016c]] ,a). Decreases in hydropower production are indicated for parts of North America, central and southern Europe, the Middle East, central Asia and Southern South America. Studies disagree on the changes in hydropower production in China, central South America, and partially in southern Africa ( [[#Hamududu--2012|Hamududu and Killingtveit 2012]] ; [[#van%20Vliet--2016b|van Vliet et al. 2016b]] ; [[#Solaun--2019|Solaun and Cerdá 2019]] ; [[#Fan--2020|Fan et al. 2020]] ).

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==== 6.5.2.2 Wind Energy ====

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Climate change will not substantially impact future wind resources and will not compromise the ability of wind energy to support low-carbon transitions ( ''high confidence'' ). Changing wind variability may have a small-to-modest impact on backup energy and storage needs ( ''low confidence'' ); however, current evidence is largely from studies focused on Europe.

Long-term global wind energy resources are not expected to substantially change in future climate scenarios ( [[#Karnauskas--2018|Karnauskas et al. 2018]] ; [[#Pryor--2020|Pryor et al. 2020]] ; [[#Yalew--2020|Yalew et al. 2020]] ). However, recent research has indicated consistent shifts in the geographic position of atmospheric jets in the high-emission scenarios ( [[#Harvey--2014|Harvey et al. 2014]] ), which would decrease wind power potentials across the Northern Hemisphere mid-latitudes and increase wind potentials across the tropics and the Southern Hemisphere. However, the climate models used to make these assessments differ in how well they can reproduce the historical wind resources and wind extremes, which raises questions about the robustness of their predictions of future wind resources ( [[#Pryor--2020|Pryor et al. 2020]] ).

There are many regional studies on changes in wind resources from climate change. For Europe, there is medium evidence and moderate agreement that wind resources are already increasing and will continue to increase in Northern Europe and decrease in Southern Europe ( [[#Carvalho--2017|Carvalho et al. 2017]] ; [[#Devis--2018|Devis et al. 2018]] ; [[#Moemken--2018|Moemken et al. 2018]] ). For North America, the various studies have low agreement for the changes in future wind resources in part because the year-to-year variations in wind resources are often larger than the future change due to climate change ( [[#Johnson--2016|Johnson and Erhardt 2016]] ; [[#Chen--2020|Chen 2020]] ; [[#Costoya--2020|Costoya et al. 2020]] ; [[#Wang--2020b|Wang et al. 2020b]] ). Studies show increases in future wind resources in windy areas in South America ( [[#Ruffato-Ferreira--2017|Ruffato-Ferreira et al. 2017]] ; [[#de%20Jong--2019|de Jong et al. 2019]] ). No robust future changes in wind resources have been identified in China ( [[#Xiong--2019|Xiong et al. 2019]] ). However, none of the global or regional studies of the effects of climate change on wind resources considers the fine-scale dependence of wind resources on the topography and wind direction ( [[#Sanz%20Rodrigo--2016|Sanz Rodrigo et al. 2016]] ; [[#Dörenkämper--2020|Dörenkämper et al. 2020]] ) or the effect of expanding wind energy exploitation ( [[#Volker--2017|Volker et al. 2017]] ; [[#Lundquist--2019|Lundquist et al. 2019]] ). There is limited evidence that extreme wind speeds, which can damage wind turbines, will increase due to climate change ( [[#Pes--2017|Pes et al. 2017]] ; [[#Pryor--2020|Pryor et al. 2020]] ). Nevertheless, projected changes in Europe and North America – regions where the most extensive analysis has been undertaken – are expected to be within the estimates embedded in the design standards of wind turbines ( [[#Pryor--2013|Pryor and Barthelmie 2013]] ).

Future wind generation in Europe could decrease in summer and autumn, increasing in winter in northern-central Europe but decreasing in southernmost Europe ( [[#Carvalho--2017|Carvalho et al. 2017]] ). Towards 2100, intra-annual variations increase in most of Europe, except around the Mediterranean area ( [[#Reyers--2016|Reyers et al. 2016]] ), but this may reflect natural multi-decadal variability ( [[#Wohland--2019b|Wohland et al. 2019b]] ). Wind speeds may become more homogeneous over large geographical regions in Europe due to climate change, increasing the likelihood of large areas experiencing high or low wind speeds simultaneously ( [[#Wohland--2017|Wohland et al. 2017]] ). These changes could result in fewer benefits in the transmission of wind generation between countries and increased system integration costs. Europe could require a modest increase (up to 7%) in backup energy towards the end of the 21st century due to more homogeneous wind conditions over Europe ( [[#Wohland--2017|Wohland et al. 2017]] ; [[#Weber--2018|Weber et al. 2018]] ). However, other studies report that the impact of climate change is substantially smaller than interannual variability, with no significant impact on the occurrence of extreme low wind production events in Europe (Van Der Wiel et al. 2019). If European electricity systems are designed to manage the effects of existing weather variability on wind power, they can likely also cope with climate change impacts on wind power ( [[#Ravestein--2018|Ravestein et al. 2018]] ). Changes in wind-generation variability caused by climate change are also reported for North America ( [[#Haupt--2016|Haupt et al. 2016]] ; [[#Losada%20Carreño--2018|Losada Carreño et al. 2018]] ), with modest impacts on electricity system operation ( [[#Craig--2019|Craig et al. 2019]] ).

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==== 6.5.2.3 Solar Energy ====

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Climate change is not expected to substantially impact global solar insolation and will not compromise the ability of solar energy to support low-carbon transitions ( ''high confidence'' ). Models show dimming and brightening in certain regions, driven by cloud, aerosol and water vapour trends ( [[IPCC:Wg3:Chapter:Chapter-12|Chapter 12]] of IPCC AR6 WGI). The increase in surface temperature, which affects all regions, decreases solar power output by reducing the PV panel efficiency. In some models and climate scenarios, the increases in solar insolation are counterbalanced by reducing efficiency due to rising surface air temperatures, which increase significantly in all models and scenarios ( [[#Jerez--2015|Jerez et al. 2015]] ; [[#Bartók--2017|Bartók et al. 2017]] ; [[#Emodi--2019|Emodi et al. 2019]] ). Increases in aerosols would reduce the solar resource available and add to maintenance costs ( [[IPCC:Wg3:Chapter:Chapter-12|Chapter 12]] of IPCC AR6 WGI).

In many emission scenarios, the effect on solar PV from temperature-induced efficiency losses is smaller than the effect expected from changes on solar insolation due to variations in water vapour and clouds in most regions. Also, future PV technologies will likely have higher efficiency, which would offset temperature-related declines ( [[#Müller--2019|Müller et al. 2019]] ). Cloud cover is projected to decrease in the subtropics (around –0.05% per year), including parts of North America, vast parts of Europe and China, South America, South Africa and Australia ( ''medium agreement'' , ''medium evidence'' ). Thus, models project modest (&lt;3%) increases in solar PV by the end of the century for southern Europe, northern and southern Africa, Central America, and the Caribbean ( [[#Emodi--2019|Emodi et al. 2019]] ). There are several studies projecting decreasing solar production, but these are generally influenced by other factors, for example, increasing air pollution ( [[#Ruosteenoja--2019|Ruosteenoja et al. 2019]] ). The multi-model means for solar insolation in regional models decrease 0.60 W m –2 per decade from 2006 to 2100 over most of Europe ( [[#Bartók--2017|Bartók et al. 2017]] ), with the most significant decreases in the Northern countries ( [[#Jerez--2015|Jerez et al. 2015]] ).

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==== 6.5.2.4 Bioenergy ====

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Climate change can affect biomass resource potential directly, via changes in the suitable range (i.e., the area where bioenergy crops can grow) and/or changes in yield, and indirectly, through changes in land availability. Increases in CO 2 concentration increase biomass yield; climate changes (e.g., temperature, precipitation, and so on) can either increase or decrease the yield and suitable range.

Climate change will shift the suitable range for bioenergy towards higher latitudes, but the net change in the total suitable area is uncertain ( ''high confidence'' ). Several studies show northward shifts in the suitable range for bioenergy in the northern hemisphere ( [[#Tuck--2006|Tuck et al. 2006]] ; [[#Barney--2010|Barney and DiTomaso 2010]] ; [[#Bellarby--2010|Bellarby et al. 2010]] ; [[#Hager--2014|Hager et al. 2014]] ; [[#Wang--2014a|Wang et al. 2014a]] ; [[#Preston--2016|Preston et al. 2016]] ; [[#Conant--2018|Conant et al. 2018]] ; [[#Cronin--2018|Cronin et al. 2018]] ), but the net effect of climate change on total suitable area varies by region, species, and climate model ( [[#Barney--2010|Barney and DiTomaso 2010]] ; [[#Hager--2014|Hager et al. 2014]] ; [[#Wang--2014a|Wang et al. 2014a]] ).

The effect of climate change on bioenergy crop yields will vary across region and feedstock ( ''high confidence'' ); however, in general, yields will decline in low latitudes ( ''medium confidence'' ) and increase in high latitudes ( ''low confidence'' ) ( [[#Haberl--2010|Haberl et al. 2010]] ; [[#Cosentino--2012|Cosentino et al. 2012]] ; [[#Preston--2016|Preston et al. 2016]] ; [[#Cronin--2018|Cronin et al. 2018]] ; [[#Mbow--2019|Mbow et al. 2019]] ). However, the average change in yield varies significantly across studies, depending on the feedstock, region, and other factors (Beringer et al. 2011; [[#Kyle--2014|Kyle et al. 2014]] ; [[#Mbow--2019|Mbow et al. 2019]] ; [[#Dolan--2020|Dolan et al. 2020]] ). Only a few studies extend the modelling of climate change impacts on bioenergy to quantify the effect on bioenergy deployment or its implications on the energy system ( [[#Calvin--2013|Calvin et al. 2013]] , 2019; [[#Kyle--2014|Kyle et al. 2014]] ; [[#Thornton--2017|Thornton et al. 2017]] ). These studies find that changes in deployment are of the same sign as changes in yield; that is, if yields increase, then deployment increases.

Some of the uncertainty in the sign and magnitude of the impacts of climate change on bioenergy potential is due to uncertainties in CO 2 fertilisation (the increase in photosynthesis due to increases in atmospheric CO 2 concentration) ( [[#Haberl--2011|Haberl et al. 2011]] ; [[#Bonjean%20Stanton--2016|Bonjean Stanton et al. 2016]] ; [[#Cronin--2018|Cronin et al. 2018]] ; [[#Solaun--2019|Solaun and Cerdá 2019]] ; [[#Yalew--2020|Yalew et al. 2020]] ). For example, earlier studies found that, without CO 2 fertilisation, climate change will reduce global bioenergy potential by about 16%; with CO 2 fertilisation, however, climate change increases this potential by 45% ( [[#Haberl--2011|Haberl et al. 2011]] ). However, newer studies in the USA find little effect of CO 2 fertilisation on switchgrass yield ( [[#Dolan--2020|Dolan et al. 2020]] ). There is also a considerable uncertainty across climate and crop models in estimating bioenergy potential ( [[#Hager--2014|Hager et al. 2014]] ).

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==== 6.5.2.5 Thermal Power Plants ====

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The operation of thermal power plants will be affected by climate change, deriving from changes in the ambient conditions like temperature, humidity and water availability ( [[#Schaeffer--2012|Schaeffer et al. 2012]] ) ( ''high confidence'' ). Changes in ambient temperature have relatively small impacts on coal-fired and nuclear power plants (Rankine cycle); however, gas-fired power plants (Brayton or combined-cycle) may have their thermal efficiency and power output significantly decreased ( [[#De%20Sa--2011|De Sa and Al Zubaidy 2011]] ; [[#Schaeffer--2012|Schaeffer et al. 2012]] ). Droughts decrease potential cooling water for thermal power plants and increase the probability of water outlet temperatures exceeding regulatory limits, leading to lower production or shutdowns. Thermal power utilisation has been reported to be, on average, 3.8% lower during drought years globally ( [[#van%20Vliet--2016c|van Vliet et al. 2016c]] ), and further significant decreases in available thermal power plant capacity due to climate change are projected ( [[#Koch--2014|Koch et al. 2014]] ; [[#van%20Vliet--2016b|van Vliet et al. 2016b]] ; [[#Yalew--2020|Yalew et al. 2020]] ). An increase in climate-related nuclear power disruptions has been reported in the past decades globally ( [[#Ahmad--2021|Ahmad 2021]] ).

Carbon capture may increase cooling water usage significantly, especially in retrofits, with up to 50% increase in water usage for coal-fired power plants globally, depending on the CCS technology (Rosa et al. 2020) ( [[#6.4|Section 6.4]] ). In Asia, planned coal capacity is expected to be vulnerable to droughts, sea level rise, and rising air temperatures, and this may be exacerbated by incorporating carbon capture ( [[#Wang--2019c|Wang et al. 2019c]] ). Recently, however, studies have proposed designs of CCS with a minimal increase in water requirements ( [[#Magneschi--2017|Magneschi et al. 2017]] ; [[#Mikunda--2021|Mikunda et al. 2021]] ).

Older thermal power plants can be retrofitted to mitigate climate impacts by altering and redesigning the cooling systems ( [[#Westlén--2018|Westlén 2018]] ), although the costs for these solutions may be high. For example, dry cooling may be used instead of once-through cooling; however, it lowers thermal efficiency and would leave plants vulnerable to ambient temperature increase ( [[#Ahmad--2021|Ahmad 2021]] ). Closed-circuit cooling is much less sensitive to water temperature than once-through cooling ( [[#Bonjean%20Stanton--2016|Bonjean Stanton et al. 2016]] ). Modifying policies and regulation of water and heat emissions from power plants may also be used to mitigate plant reliability problems induced by climate change ( [[#Eisenack--2016|Eisenack 2016]] ; [[#Mu--2020|Mu et al. 2020]] ), albeit with potential impacts for other water users and ecology. Improvements in water use and thermal efficiencies and the use of transmission capabilities over large geographical regions to mitigate risks on individual plants are also possible mitigation options ( [[#Miara--2017|Miara et al. 2017]] ).

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=== 6.5.3 Impacts on Energy Consumption ===

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Heating demand will decrease, and cooling demand will increase in response to climate change. Peak load may increase more than energy consumption, and the changing spatial and temporal load patterns can impact transmission and needs for storage, demands-side management, and peak-generating capacity ( ''high confidence'' ).

Climate change will decrease heating demands, especially in cold regions, and it will increase cooling demands, especially in warm regions ( [[#Yalew--2020|Yalew et al. 2020]] ). Recent studies report significant net impacts, with the commercial and industrial sectors and substantial air condition penetration driving an increase in energy demand ( [[#Davis--2015|Davis and Gertler 2015]] ; [[#Levesque--2018|Levesque et al. 2018]] ; [[#De%20Cian--2019|De Cian and Sue Wing 2019]] ; [[#van%20Ruijven--2019|van Ruijven et al. 2019]] ; [[#Yalew--2020|Yalew et al. 2020]] ). For example, globally, [[#De%20Cian--2019|De Cian and Sue Wing (2019)]] found a 7–17% increase in energy consumption due to climate change in 2050, with the range depending on the climate change scenario. The overall effects of climate change on building energy consumption are regionally dependent. For example, Zhang et al. (2019) find that reduced heating will outweigh increased cooling in the residential buildings in Europe, but the reverse will be true in China.

While many studies have focused on energy consumption, climate extremes are expected to alter peak energy demands, with the potential for blackouts, brownouts, and other short-term energy system impacts ( [[#Yalew--2020|Yalew et al. 2020]] ). For example, peak energy demand during heatwaves can coincide with reduced transmission and distribution capacity at higher temperatures. In large cities, extreme heat events increase cooling degree days significantly, with the urban heat island effect compounding the impact ( [[#Morakinyo--2019|Morakinyo et al. 2019]] ). One study found that total electricity consumption at the end of the century in the USA could increase on average by 20% during summer months and decrease on average by 6% in the winter ( [[#Ralston%20Fonseca--2019|Ralston Fonseca et al. 2019]] ). While the average increase in consumption is modest, climate change is projected to have severe impacts on the frequency and intensity of peak electricity loads ( [[#Auffhammer--2017|Auffhammer et al. 2017]] ). [[#Bartos--2016|Bartos et al. (2016)]] find that peak per-capita summertime load in the USA may rise by 4.2–15% by mid-century. Efficient cooling technologies and other demand-side measures can limit cooling energy loads during periods of particularly high demand (IEA 2018; [[#Dreyfus--2020|Dreyfus et al. 2020]] ).

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<span id="box-6.6-energy-resilience"></span>
=== Box 6.6 | Energy Resilience ===

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In February 2021, the state of Texas was hit by three major storms and suffered significant scale power outages. More than 4.5 million homes and businesses on the Texas electric grid were left without electricity for days, limiting the ability to heat homes during dangerously low temperatures and leading to food and clean water shortages ( [[#Busby--2021|Busby et al. 2021]] ). The Texas and other events – for example, Typhoon Haiyan in Southeast Asia in 2013; the Australian bush fires in 2019–2020; forest fires in 2018 in California; water shortages in Cape Town, South Africa in 2018 and the western USA during 2021 – raise the question of whether future low-carbon energy systems will be more or less resilient than those of today.

Some characteristics of low-carbon energy systems will make them less resilient. Droughts reduce hydroelectric electricity generation ( [[#Gleick--2016|Gleick 2016]] ; [[#van%20Vliet--2016c|van Vliet et al. 2016c]] ); wind farms do not produce electricity in calm conditions or shut down in very strong winds ( [[#Petersen--2012|Petersen and Troen 2012]] ); solar PV generation is reduced by clouds and is less efficient under extreme heat, dust storms, and wildfires ( [[#Perry--2015|Perry and Troccoli 2015]] ; [[#Jackson--2021|Jackson and Gunda 2021]] ). In addition, the electrification of heating will increase the weather dependence of electricity consumption ( [[#Staffell--2018|Staffell and Pfenninger 2018]] ; [[#Gea-Bermúdez--2021|Gea-Bermúdez et al. 2021]] ). Non-renewable generation, for example, from nuclear and fossil power plants, are also vulnerable to high temperatures and droughts as they depend on water for cooling ( [[#Cronin--2018|Cronin et al. 2018]] ; [[#Ahmad--2021|Ahmad 2021]] ).

But some aspects of low-carbon energy systems will make them more resilient. Wind and solar farms are often spread geographically, which reduces the chances of being affected by the same extreme weather event ( [[#Perera--2020|Perera et al. 2020]] ). The diversification of energy sources, in which each component has different vulnerabilities, increases resilience. Less reliance on thermal electricity generation technologies will reduce the risks of curtailment or efficiency losses from droughts and heat waves ( [[#Lohrmann--2019|Lohrmann et al. 2019]] ). More generally, increased electricity system integration and flexibility ( [[#6.4.3|Section 6.4.3]] ) and weatherisation of generators increases electricity system resilience ( [[#Busby--2021|Busby et al. 2021]] ; [[#Heffron--2021|Heffron et al. 2021]] ). Likewise, local district micro-grids with appropriate enabling technologies (e.g., distributed generation, energy storage, greater demand-side participation, electric vehicles) may ensure access to electricity during major long-duration power outage events and radically enhance the resilience of supply of essential demand ( [[#Stout--2019|Stout et al. 2019]] ).

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=== 6.5.4 Impacts on Electricity System Vulnerability ===

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While long-term trends are important for electricity system planning, short-term effects associated with loss of power can be disruptive and lead to significant economic losses along with cascading impacts on health and safety. Extreme weather and storms threaten the electricity system in different ways, affecting system resilience, reliability, and adequacy ( [[#Moreno-Mateos--2020|Moreno-Mateos et al. 2020]] ). The implications of climate change for electricity system vulnerability will depend on the degree to which climate change alters the frequency and intensity of extreme weather events. The complex compounding effects of simultaneous events (e.g., high winds and lightning occurring at the same time) are not well understood.

'''High wind speeds''' can shear lines through mechanical failure or cause lines to collide, causing transient events ( [[#Panteli--2015|Panteli and Mancarella 2015]] ; [[#Yalew--2020|Yalew et al. 2020]] ). Hurricane conditions can damage electricity system infrastructures, including utility-scale wind and solar PV plants. Electricity systems may experience high demand when lines are particularly at risk from mechanical failure from wind and storm-related effects. However, except for medium evidence of increases in heavy precipitation associated with tropical cyclones, there is limited evidence that extreme wind events will increase in frequency or intensity in the future ( [[#Kumar--2015|Kumar et al. 2015]] ; [[#Pryor--2020|Pryor et al. 2020]] ).

'''Wildfires''' pose a significant threat to electricity systems in dry conditions and arid regions ( [[#Dian--2019|Dian et al. 2019]] ). With climate change, wildfires will probably become more frequent ( [[#Flannigan--2013|Flannigan et al. 2013]] ) and more difficult to address, given that they frequently coincide with dry air and can be exacerbated by high winds ( [[#Mitchell--2013|Mitchell 2013]] ).

'''Lightning''' can cause wildfires or common-mode faults on electricity systems associated with vegetation falling on power substations or overhead lines but is more generally associated with flashovers and overloads ( [[#Balijepalli--2005|Balijepalli et al. 2005]] ). Climate change may change the probability of lightning-related events ( [[#Romps--2014|Romps et al. 2014]] ).

'''Snow and icing''' can impact overhead power lines by weighing them down beyond their mechanical limits, leading to collapse and cascading outages ( [[#Feng--2015|Feng et al. 2015]] ). Snow can also lead to flashovers on lines due to wet snow accumulation on insulators ( [[#Yaji--2014|Yaji et al. 2014]] ; [[#Croce--2018|Croce et al. 2018]] ) and snow and ice can impact wind turbines ( [[#Davis--2016|Davis et al. 2016]] ). Climate change will lower the risk of snow and ice conditions ( [[#McColl--2012|McColl et al. 2012]] ), but there is still an underlying risk of sporadic acute cold conditions such as those associated with the winter storms in Texas in 2021 (Box 6.6).

'''Flooding''' poses a threat to the transmission and distribution systems by inundating low-lying substations and underground cables. Coastal flooding also poses a threat to electricity system infrastructure. Rising sea levels from climate change and associated storm surge may also pose a significant risk for coastal electricity systems ( [[#Entriken--2012|Entriken and Lordan 2012]] ).

'''Temperature increases''' influence electricity load profiles and electricity generation, as well as potentially impact supporting information and communication infrastructure. Heat can pose direct impacts to electricity system equipment such as transformers. Referred to as ‘solar heat faults’, they occur under high temperatures and low wind speeds and can be exacerbated by the urban heat island effect ( [[#McColl--2012|McColl et al. 2012]] ). Increasing temperatures affect system adequacy by reducing electric transmission capacity, simultaneously increasing peak load due to increased air conditioning needs ( [[#Bartos--2016|Bartos et al. 2016]] ).

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=== Box 6.7 | Impacts of Renewable Energy Production on Climate ===

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While climate change will affect energy systems ( [[#6.5|Section 6.5]] ), the reverse is potentially also true: increasing the use of renewable energy sources could affect local climate. Large solar PV arrays and hydroelectric dams darken the land surface, and wind turbines extract the wind’s kinetic energy near the Earth’s surface. Their environmental impacts of renewable energy production are mostly confined to areas close to the production sources and have been shown to be trivial compared to the mitigation benefits of renewable energy ( ''high confidence'' ).

'''Solar energy.''' Observations and model simulations have addressed whether large-scale solar PV power plants can alter the local and regional climate. In rural areas at the local scale, large-scale solar PV farms change the surface characteristics and affect air temperatures ( [[#Taha--2013|Taha 2013]] ). Measurements in rural Arizona, USA show local night-time temperatures 3°C–4°C warmer at the PV farm than surroundings ( [[#Barron-Gafford--2016|Barron-Gafford et al. 2016]] ). In contrast, measurements in urban settings show that solar PV panels on roofs provide a cooling effect ( [[#Taha--2013|Taha 2013]] ; [[#Ma--2017|Ma et al. 2017]] ). On the regional scale, modelling studies suggest cooling in urban areas (0.11–0.53°C) and warming in rural areas (up to 0.27°C) ( [[#Millstein--2011|Millstein and Menon 2011]] ). Global climate model simulations show that solar panels induce regional cooling by converting part of the incoming solar energy to electricity ( [[#Hu--2016|Hu et al. 2016]] ). However, converting the generated electricity to heat in urban areas increases regional and local temperatures, compensating for the cooling effect.

'''Wind energy.''' Surface temperature changes in the vicinity of wind farms have been detected ( [[#Smith--2013|Smith et al. 2013]] ; [[#Lee--2017|Lee and Lundquist 2017]] ; [[#Takle--2019|Takle et al. 2019]] ; [[#Xia--2019|Xia et al. 2019]] ) in the form of night-time warming. Data from field campaigns suggest that a ‘suppression of cooling’ can explain the observed warming ( [[#Takle--2019|Takle et al. 2019]] ). Regional and climate models have been used to describe the interactions between turbines and the atmosphere and find minor impacts ( [[#Vautard--2014|Vautard et al. 2014]] ). More sophisticated models confirm the local warming effect of wind farms but report that the impact on the regional area is slight and occasional (Wang et al. 2019d). Wind turbines alter the transport and dissipation of momentum near the surface but do not directly impact the Earth’s energy balance

Box 6.7

( [[#Fischereit--2021|Fischereit et al. 2021]] ). However, the secondary modifications to the energy and water exchanges have added implications for the climate system ( [[#Jacobson--2012|Jacobson and Archer 2012]] ).

'''Hydropower''' ''.'' The potential climate impacts of hydropower concentrate on the GHG emissions from organic matter decomposition when the carbon cycle is altered by the flooding of the hydroelectric power plant reservoir ( [[#Ocko--2019|Ocko and Hamburg 2019]] ), but emissions from organic matter decomposition decrease over time. The darker surface of the reservoir, compared to the lighter surrounding land may counterbalance part of the reduced GHG emissions by hydropower production ( [[#Wohlfahrt--2021|Wohlfahrt et al. 2021]] ). However, these impacts vary significantly among facilities due to the surrounding land properties and the area inundated by the reservoir.

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