The South Korean government will allow solar power plants to be built in drinking-water source protection zones as it pushes toward a target of 100 gigawatts of renewable energy capacity by 2030. That means large numbers of solar installations could be built at Paldang Dam and its surrounding area, where development has been tightly restricted to protect drinking water for the greater Seoul region. The government also moved to improve rules on water use, including setting an international standard for artificial intelligence-based water treatment technology and adding treated sewage to the list of sources eligible for hydrothermal energy.
The Ministry of Climate, Energy and Environment and the Regulatory Rationalization Committee announced the measures, titled a plan to bring water industry regulation in line with competing countries, on the 19th. The aim is to revise various rules governing the water sector to stimulate both the water industry and energy businesses that use water.
The government first widened the scope for permitting solar plants inside drinking-water source protection zones. Previously, land-based solar equipment could be installed only on building rooftops, on sites for city and county facilities, and on residential lots. Under revised rules, local residents who form cooperatives such as agricultural cooperatives or forestry cooperatives can now operate solar plants, as in the so-called sunlight income villages. A clause was also added to permit floating solar projects on reservoir surfaces.
According to the Climate Ministry, floating solar projects in drinking-water source protection zones must be operated directly by the entity managing the water surface: the local government concerned, Korea Water Resources Corporation, Korea Hydro & Nuclear Power or Korea Rural Community Corporation. The restriction appears intended to guard against haphazard development that could follow private contracting. Projects also can be approved only if they use a structure in which local residents participate and share in the revenue.
The government is extending solar power even into drinking-water source protection zones, where development is normally restricted most tightly, because floating solar makes it easier to secure sites. Land-based solar requires flat, sunny plots, and in a country as small as South Korea most such land has already been taken by industrial complexes or farmland. An industry official said large-scale solar sites are hard to find in a densely populated country like South Korea, adding that the alternatives are either preserving existing land uses, as with rooftop and farmland-based solar, or using water surfaces created by reclamation projects and dams.
Linking projects to multipurpose dams also removes the need for separate substation equipment. As a result, floating solar is drawing attention around the world. According to an analysis by Wood Mackenzie, China plans to expand floating solar capacity to close to 100 gigawatts around 2034, using the large lakes clustered along the lower reaches of the Yellow and Yangtze rivers as sites for solar plants. India, at 13.5 gigawatts, Indonesia at 6.2 gigawatts and Thailand at 6 gigawatts have also announced plans for large-scale expansion. Korea Water Resources Corporation has said it aims to increase its floating solar capacity, currently about 106 megawatts, to 6.5 gigawatts after 2030.
Critics, however, say the government may be stretching too far by tapping drinking-water source protection zones in its drive to expand renewable energy. The concern is that dams whose first priority should be supplying drinking water and water for household and industrial use could end up being used primarily for renewable power generation. The protection zones now open to floating solar include Lake Paldang, Lake Juam and Lake Dongbok, which supply water to semiconductor clusters in the greater Seoul region and the southwest. Lake Paldang alone is a major source of drinking water for 26 million people in the Seoul area.
Falling output during extreme droughts is another frequently cited limitation of floating solar. If a prolonged drought pushes water levels down too far, panels can collide with structures beneath the surface or mooring equipment can fail. Efficiency also declines because water surfaces are cooler than land. Lake Unmun, whose surroundings are designated a drinking-water source protection zone, has suffered drought for six consecutive years through this year. Paldang Dam is also vulnerable because it has no flood control function of its own and, as surface water, is heavily affected by the seasons. During the summer flood season, debris washed in from the surrounding land often turns the dam into an enormous dump.
Separately, the Climate Ministry and the Regulatory Rationalization Committee announced measures to revitalize areas around dams. Until now, environmentally friendly projects near dams could be carried out only by the dam operators themselves, which lack relevant expertise. Even a campground near a dam, for example, was run directly by Korea Water Resources Corporation or a local government with no experience in such operations, leaving it poorly managed. The government will therefore revise the rules so that sites can be used through sale, lease or contracting for environmentally friendly projects. It also added cooperative-type renewable energy projects to the list eligible for water system fund programs, which support residents living near drinking-water sources, broadening the legal basis for supporting sunlight and wind income villages.
Sewage and groundwater discharge will also be added to the sources counted as hydrothermal energy under the enforcement decree of the renewable energy act. Treated sewage has until now simply been released into rivers, and the change means it can be used in hydrothermal heat pumps. A government official said Europe and Japan have actively used various forms of hydrothermal energy for more than 20 years, adding that residents living near sewage treatment plants should be able to benefit.
