Doosan Heavy Industries & Construction Co., South Korea’s biggest maker of power generators, received an order worth about $3 billion to build two power plants in Vietnam. The coal-fired generators, to be built in Quynh Lap near Hanoi and Long Phu near Ho Chi Minh City, will each have a capacity of 1,200 megawatts, Doosan Heavy said today in an e- mailed statement. A final agreement with Vietnam National Coal- Mineral Industries Group will be signed in the second half of next year, the Changwon, South Korea-based company said. Doosan Heavy said it expects to win more orders in Vietnam, where the government has forecast an 18 percent increase in power demand this year. Economic growth estimated by the government at 6.7 percent this year and 7.5 percent in 2011 is pushing up demand for electricity to power homes and factories. Vietnam needs as much as 5,000 megawatts power a year to support the country’s economic growth, Doosan Heavy said in the statement. The company fell 0.4 percent to 85,700 won as of 12:21 p.m. in Seoul trading. The stock has advanced 4.6 percent this year, compared with a 19 percent climb in South Korea’s Kospi index.