The Risk of Landslides at Japanese Solar Farms Highlights Climate Change Issues

A recent study by a team of researchers has revealed that nearly 18% of Japan’s solar farms are located within landslide hazard zones. As the frequency of heavy rainfall events intensifies due to climate change, concerns are rising about the need for stringent monitoring and disaster-prevention strategies in the renewable energy sector.

The investigation involved an analysis of data from 9,250 solar power stations sourced from the National Institute for Environmental Studies (NIES). By cross-referencing this information with government data on landslide-prone areas, the study unveiled that 1,658 solar installations, equivalent to 18% of the total, were situated within high-risk zones.

Construction of solar farms often entails deforestation and alterations to the natural landscape, reducing the land’s water-retention capacity, according to the Agriculture Ministry. The rainwater collected by solar panels could exacerbate the instability of inclined surfaces, making them more susceptible to landslides.

Experts are sounding the alarm on this issue. Takeyasu Suzuki, a professor emeritus at the University of Yamanashi with expertise in disaster prevention, warned that the threat of landslides is on the rise and emphasized the critical importance of implementing comprehensive disaster mitigation measures.

The impacts of climate change are amplifying the landslide risk. Over the past decade, the average number of torrential downpours producing 100 millimeters of precipitation per hour has increased by 50% compared to the 1980s. Recent incidents in places such as Atami in Shizuoka Prefecture and Okaya in Nagano Prefecture have tragically claimed lives due to landslides.

Concerns have also emerged regarding compliance and monitoring of solar farm operations. Since the initiation of the feed-in tariff scheme in 2012, there have been over 230 incidents involving solar stations located in forested areas. However, limited manpower within local government authorities has made it challenging to enforce regulations pertaining to tree planting and drainage systems by solar operators.

In response to these challenges, new technologies have become crucial for effective monitoring and enforcement. Last year, the government’s Forest Research and Management Organization began utilizing satellite imagery to provide nationwide data on tree cutting activities.

The surge in demand for solar energy has contributed to the construction of solar farms on sloped terrain. Following the power shortage caused by the 2011 earthquake and tsunami disaster in northeastern Japan, the introduction of the feed-in tariff system sparked the rapid expansion of the solar power infrastructure. Solar capacity has since surged to 78.83 gigawatts, marking a twelvefold increase from 2012.

Given that forests cover two-thirds of Japan, solar farm development has naturally extended to hilly areas. To address the escalating rainfall-related risks, Japanese universities are collaborating to develop weather manipulation technology capable of mitigating heavy rainfall damage. The collaborative effort aims to suppress the formation of cumulonimbus storm clouds linked to intense rainfall events. The technology is projected to be operational by 2050.

Kosei Yamaguchi, the project manager and associate professor at Kyoto University’s Disaster Prevention Research Institute, emphasized the importance of a multifaceted approach to address unforeseen situations. The researchers are also investigating methods to combat linear precipitation zones, a weather pattern associated with torrential rain. The frequency of torrential rains linked to linear precipitation zones has risen 2.2-fold over the past 45 years, according to the Japan Meteorological Agency.

The weather control project adopts principles akin to cloud seeding to counter linear precipitation zones. Instead of inducing rainfall by dispersing dry ice in the air, the technique disrupts air currents and water vapors that lead to heavy rain. Currently, the scientists are conducting computer simulations to refine these methods and aim to deploy a scaled-down version of the technology for indoor testing by around 2026.

In light of the escalating risks and consequences, flooding caused damage worth 370 billion yen ($2.6 billion) throughout Japan in 2021, as the Ministry of Land, Infrastructure, Transport and Tourism reported. The catastrophic damage incurred in 2019, largely attributed to Typhoon Hagibis, amounted to a record 2.2 trillion yen.

As Japan grapples with the dual challenges of climate change and its renewable energy ambitions, experts and authorities alike are pressed to adopt innovative strategies and technologies to safeguard against the potentially devastating impact of landslides on solar farms.

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