Imagine an energy source with the following characteristics: The fuel is free and available in unlimited supply. Power generation produces no greenhouse gases. It requires the usage of no fossil fuels.

Sound too good to be true? Well, wind power—electricity generated from harnessing the movement of wind—already exists, and its use is growing rapidly. However, while energy experts have great expectations for wind power's ability to help ease our reliance on non-renewable energy resources, there are challenges that must be met before it can realize its full potential.

The U.S. wind energy industry installed more than 5,000 megawatts (MW) of new capacity last year, shattering previous records and expanding the nation’s total wind power generation capacity by 45%, according to the American Wind Energy Association (AWEA). Texas leads the nation in wind power, with capacity approaching 4,500 MW, more than a quarter of which was installed in 2007.

Wind power is on the energy radar of states from coast to coast. Ohio, for example, recently enacted legislation calling for electric utilities to increase their usage of renewable energy sources such as wind and solar power from less than 1% of capacity currently to more than 12% by 2025.

The legislation is expected ultimately to support between 5,000 and 7,000 MW of new wind energy installations, with 650 MW to 750 MW between now and 2012, according to the AWEA. Ohio joins 25 states and the District of Columbia with renewable energy mandates, meaning a majority of all states now have such standards.

While demand for and acceptance of wind power and other renewable energy sources may well have reached the tipping point in North America, considerable challenges remain. A big one is figuring out how to get wind power from the areas where most of it is generated to the areas where it is most needed.

Wind farms can be built fairly quickly, in about a year, but the best locations are generally far from transmission lines needed to connect the farms to the utility grid. It can take five years or more to build a major transmission line. Wind power developers hesitate to build where no transmission lines exist, while utilities are reluctant to invest in lines where generation capacity does not yet exist.

There also are technical issues involved in connecting wind farms to the power grid. In Europe, a company called Airtricity has proposed a European "supergrid" as the solution. The supergrid would harness new transistor-based technology that makes it easier to connect "islanded" generation sources such as wind farms to conventional AC grid systems. A recent report by the Electric Reliability Council of Texas concludes the infrastructure needed to connect new wind power resources to the grid could be built "at a very low cost" to energy consumers, returning considerable "economic, environmental and energy security benefits."