May 16, 2012. The Seoul municipal government said it will build 29 hydrogen fuel cell power plants by 2014 to ensure a smooth supply of electricity even in emergency situations. Hydrogen fuel cells mix hydrogen and oxygen in the air to release energy through an electrochemical reaction. They produce little noise and no pollutants, leading to their use in various sectors, including in transport, power generation and homes. The city government said it plans to attract the investment of electricity firms and private capital to build the plants and also to install 102 hydrogen fuel cells in buildings by the same year. Under the plan, the city will produce 230 megawatts of electricity from hydrogen fuel cells by 2014 and continuously supply it to about 400,000 households. The power plants will be built across the city to hedge against sudden power cuts in the subway or water supply systems, the municipal government said.