Steve Harris, a principal at ZEDfactory, an architectural firm based near London that designs green residences (pictured), prefers to use a special heat-exchanging wind cowl his company has developed.

ECONOMIST: Green homes

The small, local combined-heat-and-power stations and wind turbines do receive subsidies in order to survive in competition with the big power stations.

ECONOMIST: Letters

When there is no wind, for example, heat builds up in a city, creating a low-pressure system that pulls air into the city.

CNN: In-Depth Specials - City Limits

Hundreds of thousands of people in Indiana through Maryland are still dealing with this heat without the benefits of electricity, due to a derecho -- or massive storm usually with straight-line wind damage -- that barreled eastward late Friday and into Saturday and was fueled, in part, by the extreme heat.

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