SolarEV City: Researchers Suggests Combining Solar Power With EVs in Lighting Up Cities Like Paris

Paris, the city of lights closely associated with climate change discussions since the adoption of the 2015 Paris Climate Change Agreement, is now at the center of new research from Tohuku University exploring the synergy between rooftop solar panels (photovoltaics or PVs) and electric vehicles (EVs) as a scalable solution for providing clean, cost-effective, and reliable urban electricity.

This is called the SolarEV City Concept, and it entails integrating solar panels on rooftops with electric vehicles. Beyond reducing carbon emissions from traditional gasoline and diesel vehicles, EVs play a crucial role in this concept by storing surplus electricity generated by the solar panels.

SolarEV City With PV + EV Systems

This stored energy can then be used to power homes during periods when sunlight is unavailable. However, the viability of this concept varies significantly depending on the city in question.

The study highlights that decarbonizing urban areas is of utmost importance, as they contribute to 71% to 76% of global CO2 emissions.

Achieving net-zero emissions globally necessitates substantial reductions in urban CO2 emissions. The effectiveness of the SolarEV City Concept is contingent on various factors, including local urban conditions.

An initial study conducted in Kyoto demonstrated that with 70% of the city's rooftops equipped with solar panels and a transition to all-electric vehicles, Kyoto could potentially reduce CO2 emissions from both electricity and gasoline-powered cars by 60-74% by 2030.

Moreover, it could realize energy cost savings of 22-37%. However, this concept's applicability differs in densely populated urban areas like Kawasaki and Tokyo, where reductions were less significant.

Numerous variables, such as electricity tariffs, climate conditions, and urban layouts, influence the outcomes of PV + EV systems.

Comparable studies conducted in countries like South Korea, China, and Indonesia have reported substantial emissions reductions and energy cost savings within distinct urban contexts.

Nonetheless, there has not been an investigation into PV + EV systems in high-latitude cities characterized by seasonal variations in solar insolation and electricity demand.

These variations, particularly affected by winter heating demands, were explored in a recent study examining the feasibility of the SolarEV City Concept in Paris, including the surrounding Ile-de-France region. The research also made comparisons with Kyoto as a reference city.

The SolarEV City Concept in Paris

Associate Professor Takuro Kobashi, a co-leader of the study based at Tohoku University's Graduate School of Environmental Studies, noted that in the highly urbanized city of Paris, only about 30% of its electricity needs could be met through rooftop PVs.

Additionally, the impact of EVs as energy storage devices was found to be limited due to most PV generation being consumed within the city.

However, the analysis revealed more favorable outcomes for the broader Paris region, characterized by numerous low-rise buildings. Covering 71% of rooftops in this area could fulfill 78% of the electricity demand in 2019.

Incorporating EVs as energy storage solutions allowed for the supply of approximately 60% of the required electricity, even when considering the EVs' energy demands. According to the research, this could lead to a 23% reduction in energy costs by 2030.

"Our study not only highlights the carbon reduction potential of implementing a SolarEV City in Paris and the Ile-de-France, but it shows the need to consider regional variations," Kobashi said in a press statement. The findings of the study were published in the journal Applied Energy.