South Korea is considered the world’s fourth largest oil importer, taking in 2.5 million barrels of oil daily. Yet, the current South Korean strategy is heading towards diversifying its energy sources to increase security, meet the rising energy demand, and meet the 2002 Kyoto Protocol to reduce Greenhouse Gas (GHG) emissions. The country is mainly targeting solar and wind projects as alternatives to fossil fuel, but has for some years been closely examining the potential for tidal power projects particularly along the western coastline where some stretches have tidal ranges of up to 6 meters, making it a fruitful area for tidal energy schemes.
The Sihwa Lake Tidal Power Station in South Korea is now the world's largest tidal power installation ever made. The total power output capacity of the facility is 254 MW, surpassing the second largest and the world’s first built tidal power plant, the Rance Tidal Power Station in France, with a capacity of 240 MW. The Sihwa Lake Tidal Power Station is now being operated by the Korean Water Resource Corporation. The project is stationed on Lake Sihwa which is located in the Midwest of the Korean Peninsula in Gyeonggi Province, bordering the West Sea at the Lake Sihwa region around 4 km from the city of Siheung.
The tidal barrage makes use of a seawall constructed in 1994 for flood mitigation and agricultural purposes. Ten submerged bulb turbines, with a capacity of 25.4 MW each, are driven in an un-pumped flood generation scheme; power is generated on tidal inflows only and the outflow is sluiced away. This slightly unconventional and relatively inefficient approach has been chosen to balance a complex mix of existing land use, water use, conservation, environmental and power generation considerations.
The tidal power station provides indirect environmental benefits as well as renewable energy generation. After the seawall was built, pollution built up in the newly created Sihwa Lake reservoir, making its water useless for agriculture. In 2004, seawater was reintroduced in the hope of flushing out contamination; inflows from the tidal barrage are envisaged as a complementary permanent solution.
Cost of the project was met by the South Korean Government, totaling about 280 million USD. Mean operating tidal range is 5.6 m, with a spring tidal range of 7.8 m. The working basin area was originally intended to be 43 km2 although this has been reduced by land reclamation and freshwater dykes. The basin will eventually be only around 30 km2.
It is worth mentioning that the Sihwa Tidal Power Station has successfully substituted what is equivalent to 862,000 oil barrels of annual fossil fuel used in power generation in South Korea. This reduction in fossil fuel consumption led to reducing the annual emission rate of carbon dioxide in South Korea to 315,000 tons per year.