Previously, he said, maybe just 1 percent of developing nations was judged sufficiently windy, discouraging governments and investors from considering the nonpolluting source as an alternative to burning oil, coal or natural gas.

The new maps, part of a $9.3 million study, use data from satellites, balloons and other sources to model winds in 19 developing nations.

In the past, wind potential was based on data from meteorological stations that were often built in Third World countries too close to trees or buildings which braked winds.

Or winds were typically gauged at airports - not built in the windiest locations. "It's very consistent," Hamlin said. "The weather data was not reliable and generally low."

Among the nations surveyed, Nicaragua, Mongolia and Vietnam had the greatest potential with about 40 percent of the land area suitable for windmills.

Least promising was Bangladesh, with just 0.2 percent of the land area suited to windmills, along with countries including Cuba and Ghana.

Hamlin said the UN maps, part of the Solar and Wind Energy Resource Assessment, could help poor nations facing high bills for oil imports. "A lot of what's really driving investments is the price of oil," he said.

In Nicaragua, for instance, the government in the 1980s estimated the nation's wind power potential at just 200 megawatts. The UN map estimates its potential at 40,000 megawatts, a rough equivalent of 40 nuclear power plants.

The study defines suitable areas as those that could generate 300 watts per square metre (10.8 square feet), needing winds of at least 6.4-7.0 metres (21-23 feet) per second at 50 metres (164 feet) above the ground.