The project will start with the construction of a 7.8-km-long dam connecting the four islands of Ganghwa, Gyodong, Seokmo and Seogeom at a cost of W1.78 trillion (US$1=W927). It should be finished by 2014. Following the installation of 32 tidal power generators, power will begin to flow in 2015.

Incheon and the builders will next month sign an official agreement with more details including management information and a budget, based on a research report by Daewoo E&C. The project must first be approved by the Ministry of Commerce, Industry and Energy.

Tidal power plants generate electricity by using tidal currents to spin turbines. Dams are built in places where the difference between the ebb and flow of the tide is high.

The dam includes a sluice that opens to allow the tide to flow into a basin. The sluice is then closed, and as the sea level drops, it lets the water fall to turn the turbine and generate electricity.

Traditional hydro-power plants generate electricity from body of water that must be higher in elevation than the turbines. The Incheon island group has a high tidal difference, with a maximum of 7.64m and an average of 5.57m.

At 812 megawatts (MW), the Ganghwa plant will have the largest output capacity of any tidal plant in the world, the city said. The current largest is the Rance tidal plant in France with a capacity of 240MW, while another plant under construction in Shihwa Lake will have a capacity of 254MW.

(englishnews@chosun.com )