The number of mega solar plants in Japan is increasing. Yet, it can be difficult to see the overall picture. From a personal perspective, I’ve seen only those near my home and at travel destinations.
However, a joint research project conducted by the National Institute for Environmental Studies’ Center for Climate Change Adaptation and a similar environmental research center has connected the dots and, using satellite images, fully confirmed the distribution of solar facilities in Japan.
How much land in Japan’s mountains and countryside is taken up by solar facilities?
The above-mentioned research, seeking to answer these questions, has helped to shine a light on the proliferation of mega solar plants in Japan.
Nearly 9,000 Solar Facilities Identified
The research team looked at solar facilities in Japan with a power generation capacity of at least 0.5 megawatts, and put together a package of digital data on them.
The “Electrical Japan” database, which has basic information on solar facilities, was used in combination with satellite images and aerial photographs assembled by the research team. Together, they allowed the team to identify 8,725 facilities.
A 0.5 megawatt-facility, depending on the performance of the solar panels, takes up an area of about 50 meters by 100 meters. In a rural setting, this stands out to have a considerably large environmental impact.
When the land areas occupied by all identified solar facilities with a generation capacity of at least 0.5 megawatts are added together, the facilities take up about 229 square kilometers.
That’s about 3.6 times the size of the area inside Tokyo’s JR Yamanote passenger railway line. Moreover, if facilities with a capacity of less than 0.5 megawatts are added, the total land area they occupy is even larger.
Disappearing Natural Spaces
The team, which acknowledges the importance of the location of renewable power sites, also analyzed the location dynamics of solar facilities.
First, location trends. After looking at old satellite images showing the kind of land taken up by solar facilities, it was found that many of the solar energy sites were situated in the natural areas referred to as satoyama, the rich natural areas between the plains and mountain foothills that used to be secondary forests, fields, meadows, and rice paddies.
Comparing past and current satellite images, it was clear that many of these natural spaces had been replaced by solar energy facilities.
Moreover, the team discovered that 1,027 solar facilities had taken up a total area of 35 square kilometers across wildlife sanctuaries and national parks, which are key nature areas.
The research team created a mathematical model that takes natural conditions and social conditions around the sites chosen for solar facilities, and developed a method for interpreting and predicting their likelihood of expansion in the future.
Under natural conditions, the team listed items such as climate, terrain, the risk of landslides, and the distance from rivers. For social conditions, it looked at such factors as population density, land prices, and traffic density.
The scale of the sites was also considered. Therefore, in the model, there were two groups: medium-sized facilities between 0.5 and 10 megawatts, and large-scale facilities with a higher level of power generation.
Jun Nishihiro of the Center for Climate Change Adaptation, explained, “Regarding photovoltaic energy generation (solar power), I think the advantages and disadvantages should be made clear, enabling the affected regions to make informed decisions.”
This particular subject reminds one of the conversations of the trees and the flowers in folklore, such as “Solomon’s Ring” and other such traditional stories. Updated, they go something like this:
“We solar panels are like plants, aren’t we?”
“Yes! We like to be in areas that have a lot of sunshine.”
“But that means there is competition for the best spots. In Western Japan, there are more and more solar panels floating on ponds and reservoirs, but the effects of these panels on the wildlife and ecosystems are apparently a concern.”
“The native waterfowl are unhappy, and it’s sad that ducks that migrate in winter are losing places to go when it’s cold.”
“Maybe the solar panels that use sunlight are simply ‘artificial plants’ born out of technology, don’t you think?”
“In ecology, they use the term climax, which refers to a community of plants and animals that has reached a settled, steady state. But this climax of solar panel forests is like a ‘silent spring,’ isn’t it?”
Japan is aiming to be a decarbonized society by 2050, but at the same time, coexistence with biodiversity is vital.
If trees are cut down to make way for solar facilities, then wildlife will suffer — something that goes against the philosophy of a green society, and a story similar to that of the deforestation of the Amazon rainforest.
Conservation of the ecosystems is a major issue in the areas used for solar power generation, which require large areas of land.
The Japanese government is planning to introduce more solar power generation, but pursuing a decarbonized society at low cost could have damaging effects on the Japanese archipelago.
(Read the Sankei Shimbun story in Japanese at this link.)
Author: Shohei Nagatsuji