Daytime charging of electric vehicles further expands adoption of photovoltaics

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Electric vehicle (EV) sales are approaching one quarter of all vehicle sales. In China, the EV sales fraction may reach 50% this year. China is the world’s largest EV market and also the world’s largest EV manufacturer. The approaching saturation of the home market means that a flood of competitively priced Chinese EV exports can be expected, leading to continued rapid growth in global EV sales.

EV sales grew 25% in 2024 compared to 2023 to over 17 million passenger and light-duty EVs sold last year. Assuming that electricity demand per vehicle averages 10 kWh/day, this implies growth in electricity demand of about 60 TWh per annum. Fossil fuel generation has flatlined since 2021. Thus, virtually all extra electricity demand is being met by new solar and wind energy.

Most existing vehicles in the world today, overwhelmingly petrol vehicles, will retire by 2040. We can confidently expect that most new vehicle sales in the 2030s will be electric, meaning continued rises in demand for solar and wind energy. Roughly speaking, complete electrification of the land vehicle fleet in an advanced economy adds 40% to electricity demand. This new demand will be sourced from solar and wind.

As ZareAfifi, de Castro and Kurtz have recently discussed, daytime charging of EVs is a powerful game-changer, leveraging flexible EV loads to maintain solar value on the grid and aligning EV charging loads with solar generation. If the uptake of PV expands at a faster pace than complementary storage solutions on the grid, then its marginal grid value diminishes, reducing its economic appeal due to a growing lack of alignment between new solar generation and electricity loads. EVs are “batteries on wheels” that can be charged during sunshine hours with solar electricity and discharged to the grid at any time, offering short-duration energy storage to address nighttime demand. The timing of EV charging thus becomes key.

The widespread installation of slow-charging infrastructure in both residential and non-residential settings such as workplaces where cars are parked for several hours during weekdays, could make daytime charging more economically and practically attractive. Time-of-use rates reflecting daytime hours align with the availability of the cleanest and most cost-competitive electricity, leveraging solar PV at its peak production.

At the current pace, by the end of the decade, the cumulative installed capacity of solar PV will be larger than the sum of all the other electricity generation technologies combined. As PV adoption grows, curtailment of solar electricity at peak production times starts to become an issue, and large new loads that match the solar resource availability, such as EV charging during daytime, are welcome additions.

2024 Demand 737.5
Grid Residential 80996.6
Grid Commercial 655165.6
Grid Utility Owned 36.8
Off Grid/Other 1305.6
Total 737504.7
Installations 476.3
Inventory and other 261.2

 

Breakdown of solar PV demand in 2024. Total demand was 737.5 GW. Reprinted with permission from P. Mints, Solar Flare Issue 1, 2025. https://www.spvmarketresearch.com/

Breakdown of solar PV demand in 2024. Total demand was 737.5 GW. Reprinted with permission from P. Mints, Solar Flare Issue 1, 2025.

https://www.spvmarketresearch.com/

Breakdown of solar PV demand in 2024. Total demand was 737.5 GW. Reprinted with permission from P. Mints, Solar Flare Issue 1, 2025.

https://www.spvmarketresearch.com/

Authors: Prof. Ricardo Rüther (UFSC), Prof. Andrew Blakers /ANU

Andrew.blakers@anu.edu.au

rruther@gmail.com

ISES, the International Solar Energy Society is a UN-accredited membership NGO founded in 1954 working towards a world with 100% renewable energy for all, used efficiently and wisely.

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