Harnessing wind energy has a long history. In China and Egypt, archeologists have found “windmills” — used to grind grain and pump water — dating as far back as 500 BC. Windmills have been in use ever since. But in the early 1970s, when oil embargoes caused acute energy shortages in the United States, harnessing the wind took on greater importance as not only another power source, but as a renewable energy power source.