Solar power facilities in Japan and South Korea can destroy substantial amounts of wildlife habitats, but building future plants in urban areas could mitigate the damage, scientists have reported.

The researchers used satellite images to examine the impacts of solar photovoltaics facilities on natural landscapes and found that midsized plants cumulatively caused more habitat loss than large ones. The team published the findings March 16 in Science of the Total Environment.

"The amount of habitat loss by medium solar [facilities] was much larger than we expected," said first study author Ji Yoon Kim, a research associate at the Center for Climate Change Adaptation at the National Institute for Environmental Studies, in Japan. "We stressed the need to update the current solar [photovoltaics] site-selection criteria and to consider cumulative habitat loss in the environment assessment planning."

Transitioning to renewable forms of energy is essential to reducing greenhouse gas emissions and minimizing the effects of climate change, Kim said. He and his colleagues noted in the study that solar photovoltaic power accounts for more than half of the annual renewable energy market, according to the Renewables 2020 Global Status Report. 

In the United States, the Biden administration recently announced plans to transition the electricity grid away from fossil fuels by 2035. 

"To reach that goal in the next 15 years, hundreds of gigawatts of solar energy need to be installed as much as five times faster than it is now," according to the Department of Energy.

However, solar facilities demand a lot more space to generate the same amount of energy as fossil fuel or nuclear plants. And the construction of solar photovoltaics facilities can have profound impacts on an area's biodiversity and physical environment, such as breaking up natural habitats into smaller isolated fragments. 

Until now, environmental concerns relating to solar power have mostly focused on large-scale facilities that can generate more than 10 megawatts of electricity. Kim and his colleagues were curious about the impacts of medium-sized solar photovoltaics facilities, which can generate 0.5 to 10 megawatts. 

They investigated the amount of habitat loss caused by the construction of medium-sized and large solar plants in Japan and South Korea. These countries aim to have 20% to 24% of their power supply come from renewable sources by 2030, and to reach net-zero greenhouse gas emissions by 2050.

Kim and his team identified 12,098 solar photovoltaics facilities and used satellite images and aerial photos to compare the landscapes before and after the plants were constructed. They found that the number of medium-sized facilities was 31.7 and 110.1 times larger than that of large ones in Japan and South Korea, respectively. Additionally, medium-sized plants caused 66.36% and 85.73% of the habitat loss in Japan and South Korea, respectively.  

This damage was especially felt in secondary forests and grasslands, which are areas regrowing after a disturbance, and agricultural lands. Although fragmented, these habitats still play important ecological roles in otherwise developed regions, Kim said.

Moreover, the team found that a number of solar facilities had been constructed within national conservation areas, and more than two-thirds of these facilities were medium-sized.

Based on where solar facilities were constructed, and the surrounding conditions, the team determined that, unsurprisingly, developers chose areas with abundant sunshine, low land prices and other qualities that would make the facilities easier and more efficient to build and operate. 

By contrast, environmental protection didn't seem to be a priority. 

"Even conservation areas were developed when economic and topological conditions were suitable for energy production," Kim and his colleagues wrote in the paper. "Construction of solar [photovoltaics facilities] in natural habitats and conservation areas indicated a limited consideration of biodiversity within the process of site selection for renewable energy projects." 

The researchers also estimated future habitat loss under different scenarios in which solar power increased to meet the renewable energy targets set by Japan and South Korea for the next several decades. The team compared these projections to several scenarios in which construction was restricted in conservation areas and encouraged in more urban landscapes, including on rooftops and building surfaces.

"Our scenario projection showed that the restriction of solar power installations in conservation areas may not be enough to conserve overall natural habitats," Kim said. He added that when the team considered policies that both restrict construction in conservation areas and promote it in urban areas with incentives, "That can conserve more natural habitat."

Medium-sized facilities are easier to build under current regulations and can be built in locations with steeper slopes or in those that would otherwise be unsuitable for larger plants. The findings indicate that medium-sized plants shouldn't be neglected when researchers are considering the environmental impacts of photovoltaics and how to limit them.

"Although [the] current study quantifies the amount of physical loss of natural habitat and conservation areas, it is still challenging to assess how severely the biodiversity or ecological functions in natural habitat will be affected," Kim said. "We would like to expand our study to quantify the environmental impact of renewable energy on the habitat quality and ecological functions."

The study, "Current site planning of medium to large solar power systems accelerates the loss of the remaining semi-natural and agricultural habitats," published March 16 in Science of the Total Environment, was authored by Ji Yoon Kim, Dai Koide, Fumiko Ishihama, Taku Kadoya and Jun Nishihiro, National Institute for Environmental Studies.