Floating solar power plants will be allowed on Paldang Dam, the largest protected drinking water source in the greater Seoul area, as the government scrapes together every available site to meet its target of 100 gigawatts of renewable energy by 2030.
The Ministry of Climate, Energy and Environment and the Regulatory Rationalization Committee announced the measures on the 19th as part of a plan to bring water industry rules in line with those of competing countries. The aim is to revise regulations to spur growth in the water industry and in energy businesses that use water.
The government first widened the scope for building solar plants inside protected water source areas. Previously, ground-mounted solar equipment could be installed only on building rooftops, city and county facility sites, and residential lots within those areas. Under the revised rules, residents who form a cooperative, such as an agricultural or forestry cooperative in a so-called sunlight income village, may also operate a solar plant. A new provision allows floating solar projects on reservoir surfaces as well.
According to the ministry, floating solar projects in protected water source areas 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 prevent haphazard development that could follow from outsourcing to private operators. Projects will also be approved only if they involve local residents and share revenue with them.
The government is extending solar power even into protected water source areas, where development is normally restricted most tightly, because floating solar makes it easier to secure sites. Ground-mounted solar requires land with good sun exposure and little slope, but in a country as small as Korea most such land has already been taken by industrial complexes or farmland. "In a place as densely populated as Korea, it is hard to find sites for large-scale solar plants," an industry official said. "In the end the alternatives are to keep using existing land, as with rooftop or agrivoltaic systems, or to turn to floating solar on reclaimed land and water surfaces created by dams."
Linking projects to multipurpose dams also removes the need for separate substation equipment. Korea Water Resources Corporation has said it plans to expand its floating solar capacity to 6.5 gigawatts by 2030 from the current 106 megawatts.
Critics argue, however, that the government is pushing too far into protected water source areas in its drive to expand renewable energy. The concern is that dams whose first priority should be supplying drinking, household and industrial water could end up serving power generation instead. The protected areas newly opened to floating solar include Paldang Lake, Juam Lake and Dongbok Lake, which supply water to semiconductor clusters in the greater Seoul area and the southwest. Paldang Lake alone provides drinking water for 26 million people in the capital region.
Falling output during extreme drought is another widely cited limitation of floating solar. If a prolonged drought pushes water levels too low, panels can strike submerged structures or mooring systems can fail. Water surfaces are also cooler than land, which reduces solar efficiency. Unmun Lake, which is surrounded by a protected water source area, has suffered drought for six straight years through this year. Paldang Dam is further exposed because it has no flood control function of its own and draws on surface water, leaving it heavily affected by the seasons. During the summer flood season, debris washed in from the surrounding land often turns the dam into a vast dumping ground.
The ministry and the committee also announced measures to revitalize areas around dams. Until now, eco-friendly businesses near dams could be run only by the dam operators themselves, which lacked relevant expertise. Even plans for a campground near a dam, for example, were poorly run because Korea Water Resources Corporation or local governments had to operate them directly without experience in the field. The government will revise the system so that sites can be sold, leased or entrusted to others for eco-friendly projects. It will also add cooperative-based renewable energy projects to the list of initiatives eligible for watershed fund support, which is used to assist residents near water sources, broadening the basis for backing sunlight and wind income villages.
The government is also improving rules on water use, including setting an international standard for artificial intelligence-based water treatment plants and adding treated wastewater to the list of sources eligible for water-source (aquathermal) heat energy. Sewage and groundwater discharge will be included as hydrothermal energy sources under the enforcement decree of the renewable energy act. Treated sewage, previously discharged into rivers, will instead be used in hydrothermal heat pumps.