Future changes in solar radiation and rising temperatures will likely reduce global solar photovoltaic potential, but advancing photovoltaic technologies could counteract these effects. We investigate the potential of photovoltaic to satisfy energy demands given climate change and technological development. We find that conventional photovoltaic will require 0.5 to 1.2% of global land area to meet projected energy demands by 2085 without accounting for climate change effects. When considering climate impacts, this requirement increases to 0.7–1.5% of the global land area. However, utilising advanced photovoltaic technologies can reduce this area to 0.3–1.2%, effectively mitigating climate impacts. Regional climate change impacts vary substantially, resulting in photovoltaic potential decreases of up to 3% in Latin America and the Caribbean, and by up to 8% in South Asia. Our results suggest that technology-driven increases in future global photovoltaic energy production can more than compensate for the climate related reductions.
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Introduction
Solar photovoltaic (PV) is an increasingly important source of clean energy and is currently the third-largest renewable energy source after hydropower and wind, accounting for 3.6% of global energy production1,2. PV energy production grew by 22% (179 TWh) in the year 2020–2021, and a 25% average annual growth rate between 2022 and 2030 would be consistent with net-zero scenarios1 by 2050. Past projections have consistently underestimated the rate of PV deployment3, and the required acceleration in future growth may well be feasible.
A key factor to consider, however, is how much land area would be required to satisfy the global energy demand under different socio-economic and climate change futures4– and the extent to which improvements in PV technology will increase PV output. This is important because future changes in solar radiation and increasing temperatures arising from climate change will likely reduce global PV potential4. The PV capacity installed today is likely to remain in place for the next 20–30 years, but the rate at which the development and deployment of more efficient PV technologies that would offset climate change impacts is uncertain.
Previous research on climate change impacts using projections from general circulation models (GCMs) indicates varying effects on different types of PV systems; for example, a decline in global PV potential of up to 0.4% for large-scale PV, but an increase in rooftop PV potential of 2% by 21005. However, localized changes in the PV potential of existing PV installations6,7 under climate change scenarios range from ?19% to +16%4. Studies using regional climate models (RCMs) have projected PV potential declines of up to 20% in South Asia and Latin America8 and 34% in Sweden9. However, counteracting improvements in technology have not been consistently explored across regions, PV technologies, or climate change scenarios10,11.
Previous analyses have argued that the scope for large-scale PV deployment is limited because of competition with other land uses12,13. Some land uses, however, are multifunctional, such as agri-voltaic systems14. Pastures are generally well-suited to agri-voltaic systems in which solar panels are placed above grazing livestock. Such systems produce both electricity and food, and potentially benefit from shading for grazing animals and grass15. Other land uses with the potential for multifunctional PV deployment include highways, car parks and irrigation canals with PV panel shading16, and urban roof-tops17. In combination with technology improvements, these could substantially reduce land requirements for PV energy.
A few studies4,5 analysed climate change impacts on global PV potential for specific scenarios of climate change and advances in PV technology but without consideration of how the two could affect the global land requirement for PV installations. In this study, we analyse the global PV land area requirements to meet future energy demands, and how this land area changes under different climate futures and for more efficient PV technologies.
To explore the implications for future global PV potential, we pose the following research questions;
- 1. How much land area would be required for PV deployment to meet future energy demands under conventional and advanced PV technologies?
- 2. How do these land areas vary when the direct impacts of climate change on PV energy generation are accounted for?
- 3. How do PV potential and land area requirements vary when PV is combined with other land uses?
We address these questions using climate change scenarios for four Representative Concentration Pathways (RCPs; RCP2.6, RCP4.5, RCP6.0 and RCP8.5) from four General Circulation Models (GCMs), considering six different PV technologies, as described in the Methods section. We also use projections of future global energy demands for the shared socio-economic pathways (SSPs; SSP1, SSP2, SSP3, SSP4 and SSP5)18,19.
Results
How much land area would be required for PV deployment to meet future energy demands under conventional and advanced PV technologies?
The land area required for PV to satisfy potential global energy demand depends strongly, among other factors, on the technology used. Conventional Si PV module technology would require around 0.5–1.2% of the global land area to fulfil the projected energy demand for different SSP scenarios19, if placed to maximise energy generation (Fig. 1). Different world regions would require varying proportions of land to meet the energy demands for different SSP scenarios (Fig. 1), with East Asia and the Pacific, and Middle East and North Africa, requiring the most land area (see Table 1). However, if the conventional Si technology is replaced by more efficient PV technologies such as perovskites and III-V cells multijunctions (more details in Supplementary Table. 1), much less land would be needed to meet global energy demands (Table 1); just 0.3–1.0 % of the land area (between about one half and three-quarters of the area required for Si PV modules) (Fig. 1). Similar to the conventional Si case, these requirements vary regionally (Table 1) across the SSP scenarios (Fig. 1). They also vary according to treatment of site-specific variables such as the ground coverage ratio (GCR); with a standard value for this applied (more details in the Methods section), the land requirement would be: conventional Si (1.0–2.4%), perovskites (0.8–1.8%), and III-V cells multijunctions (0.5–1.1%) (Supplementary Fig. 1). This makes the total PV land area requirement needed to meet future energy demands equivalent to the current global urban area20,21.
Table 1 Land areas (as percentage of global total land) required to meet energy demand using PV under different scenarios, and the change in PV potential due to climate change
How do land areas vary when the direct impacts of climate change on PV energy generation are accounted for?
The projected slight increase in global mean annual incident solar radiation (?+?0.8% to +1.2% in 2050, and +0.4% to +1.0% in 2085) and the anticipated rise in mean temperature (?+?1.5?°C to +2.7?°C in 2050, and +1.5?°C to +5.0?°C in 2085) relative to the baseline (1991–2005) led to modelled declines in PV potential (?3.7 to ?4.5% in 2050 (2031–2070), and ?3.4 to ?5.0% in 2085 (2071–2100)) across the climate scenarios (Fig. 2). This is mainly because higher temperatures reduce PV panel efficiency by between 0.4 and 0.5% for every 1?°C increase above a panel temperature of 25?C22 (Fig. 3). Our univariate sensitivity analysis of climate variables (solar radiation and temperature) provides further insights to explain these differences. The analysis showed that when the temperature was kept constant but the radiation varied, there was an increase in PV potential. However, when considering the effect of temperature alone, PV potential decreased (see Supplementary Fig. 2). Different temperature trajectories among scenarios and regions contribute strongly to the varying regional impacts that we find (see Table 1, Fig. 2).
We therefore present a detailed global and regional assessment of climate change impacts on PV potential (Fig. 2, Supplementary Note 2) and land area requirements (discussed below). The climate change impacts show strong regional differences, with PV potential decrease of up to ?3% in Latin America and the Caribbean, and by up to ?8% in South Asia. These changes are more moderate compared with previous studies4, which analysed climate change impacts on existing PV sites globally and found a decline of up to 19% and an increase of up to 16% in the most affected sites.
The global mean PV potential varies between 359 and 1495?kWh/kWp (kilowatt hours per installed kilowatt-peak of the system capacity) depending on the losses23 considered in the estimation of PV potential4 across the climate scenarios (Supplementary Fig. 3). Using typical values for losses, ranges are much more restricted, with a global potential of 1340–1363 kWh/kWp. The largest regional value is in Sub-Saharan Africa (1621–1661 kWh/kWp), and the smallest is in Europe and Central Asia (976–989 kWh/kWp) (Supplementary Fig. 3, Supplementary Table. 1)4.
The combined effects of solar radiation and temperature changes produced declining trends in PV potential which explain the decline in global PV potential over the 21st century across climate scenarios (Supplementary Fig. 2)24,25. Speed of roll-out of new technologies, reducing costs26, and policy support for solar panels would enable PV to overcome these impacts, however27, suggesting that future PV energy production is resilient to climate change. However, technological development could enable PV deployment to overcome the negative impacts of climate change, as discussed below.
Climate neutrality requires a fast energy transition from conventional fossil fuels to renewable energy sources28,29, and solar PV power has immense potential to contribute to this transition, especially if emerging technologies fulfil their promise. However, the generation of solar PV energy will be impacted by climate change (discussed above), leading to a decline in the contribution of solar PV to future energy demands. As a consequence, to achieve a similar level of energy production, the land area under PV would need to be increased by, for example, 1.5% (or 3% when GCR is considered, Supplementary Fig. 5) of the global land area using conventional Si in a high- emission scenario (i.e., SSP5-RCP8.5; Fig. 4 & Supplementary Fig. 4). However, technology can offset the negative impacts of climate change as shown in Fig. 4. For example, only 0.7% (or 1.4% when GCR is considered Supplementary Fig. 6) of the global land area would be needed to meet the energy demand in the same scenario using III-V Multijunctions PV technology (Fig. 4). The benefits of technology in compensating for negative climate change effects will, however, depend on the rate of roll-out of new technology30. Meeting global energy demand from PV in 2085 (2071–2100) under the SSP-RCP scenarios would require 0.7–1.5% (conventional Si) of the global land area (Fig. 4), which is around 0.2–0.3 percentage points more than in the absence of climate change (Fig. 1).
The sub-global land requirements would also increase (Table 1), for example by up to 0.2–0.5 percentage points in South Asia and East Asia and Pacific, 0.3–0.7 percentage points in the Middle East and North Africa, or just 0.02–0.04 percentage points in Sub-Saharan Africa (Fig. 4, Table 1). The large scope for PV production in Sub-Saharan Africa (with 14.7% of the current global population according to Our World in Data31) could play a crucial role in economic development and social well-being within the region. It could not only meet societal energy demands (potentially generating 6 to 26 times the regional energy demand, depending on the PV technology used and on assumed 0.5–1.0% of the global land area) (Supplementary Table. 2) but also provide new job opportunities through the PV sector. Likewise, the Middle East and North Africa (with 7.2% of the current global population) could generate 0.3 to 1.3 times their regional energy demand by 2050. This presents an alternative energy source even in the most fossil-fuel-dependent scenario, though it would require more land (Supplementary Table. 2). These regions include countries with a large potential for economic development that would need to be supported by sufficient energy. Likewise, the most populated regions of the world (East Asia together with Europe) have 31% of the current global population and could also meet their future energy demands from PV, since the PV potential in these regions will not change substantially in the future. The second most populated region, South Asia (25% of the current global population) will likely experience some local declines in PV potential under different climate scenarios, but will still retain huge potential (0.3 to 1.3 times the regional demand under high fossil fuel scenarios) for PV at larger scales32.
How does PV potential vary when combined with other land uses?
The global land area is limited and there is competition for land between multiple uses (including food, fibre and timber production). Identifying where PV could be deployed that would least affect other land-use is, therefore, critical. As an (hypothetical) example, the unpopulated area of the Sahara Desert is around 9 million k m2 (around 7% of the global land area). If this area were to be used for conventional Si PV deployment, around 5–11 times the global energy demand in 2085 across the SSP-RCP scenarios could be produced (Fig. 5). An alternative, arguably more realistic perspective is to consider the energy production arising from deploying PV on the 0.7% of global land area covered by highways as a shaded infrastructure, which could generate around 1.2 times more energy than demanded in 2085 under SSP1-RCP2.6 (though slightly less than demanded in other SSP-RCP scenarios). Moreover, replacing conventional urban infrastructure with PV-based infrastructure could be a substantial step toward energy sector transformation. Projections suggest that urban areas could range from about 1.1 million to 3.6 million k m2 across the SSP scenarios (around 0.8%–2.6% of the global land area)21 by 2100. Considering the high energy demands in urban areas, utilising building facades, rooftops, footpaths, parking lots and other urban infrastructure for PV deployment could provide 1.4 to 4.2 times the energy demanded in 2085 across scenarios (Fig. 5). Alternatively, pastures could be used for large scale PV deployment as a multifunctional land-use. Depending on how grasslands are defined, they account for between 20% and 40% of the global land area33, with 2% of these (i.e., 0.4–0.8% of the global land area) being intensive pasture33. If parts of these areas were used for PV energy production, they could generate 0.3–1.3 times the global energy demand while still retaining potential for livestock production (Fig. 5), depending on location, and with small additional negative impacts on biodiversity.
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