Regulations and mandates that force nationwide cuts in carbon dioxide emissions offer only speculative environmental benefits, if any, as a switch to wind and solar power will certainly cause more harm than good to the environment.

But command-and-control forces in Congress are headed in that direction, with the House narrowly passing a bill to cap CO2 emissions, and the Senate taking up a companion bill this month.

Engineers calculate that a stunning 600 square miles of wind turbines would be needed to produce the same 1,000 megawatts of electricity as a single medium-to-large coal power plant. That's enough to provide electricity to about 10,000 homes.

Even in favorable locations, wind turbines can supply electrical power only about 20 percent of the time, meaning utilities still must have an alternative baseload source to compensate for wind fluctuations, and those alternatives are three: coal, natural gas or nuclear power plants. But by taking coal and natural gas out of production due to carbon dioxide restrictions, a massive and enormously expensive program will be needed to build more nuclear power plants to supply this baseload.

Further, wind turbine developments despoil nature's beauty, and indiscriminately kill birds and bats, including many endangered species.

Writing last summer in the Boston Globe, Eleanor Tillinghast, director of the environmental advocacy group Green Berkshires, warned, "Cutting wide swaths of unspoiled forest for access roads, clear-cutting miles of ridgelines, erecting industrial structures with spinning blades that threaten migrating birds and the last remaining bats - these are irreversible actions with permanent consequences."

Solar power likewise requires substantially more environmental destruction than coal. The Nevada Solar One array, the most efficient in the nation, requires 350 acres of land to produce less than 1/10th the power of a conventional coal-fueled power plant, and that's at peak efficiency at noon on a cloudless day.

Both wind and solar power projects inevitably would require the construction of new transmission lines, often across otherwise-pristine lands, to reach energy-hungry consumers. The nation's key wind corridor, from the Texas panhandle to the Dakotas, contains no major population center.

Further, wind and solar generators consume much more water than coal power plants, a serious problem in desert areas with the most sunlight.

All of that explains why so many environmentalists oppose further development of wind and solar power. By forcing construction of more of these projects, carbon dioxide restrictions will have a devastating impact on many of America's most valuable natural treasures.

Dan Miller is publisher at The Heartland Institute and former chairman of the Illinois Commerce Commission, the public utility regulatory body in Illinois.