How should we generate our electricity in the future? Concerns about air pollution, global warming and high energy prices have prompted an unprecedented discussion about something most people have taken for granted all of their lives.

During the 1990s, natural gas was viewed as the low-cost, clean solution for generating electricity, and as a result, about 40 percent of the nation's current generation capacity uses natural gas. But the price of gas has tripled and concerns about global warming have appeared, making it far less attractive than before.

Coal-fired electricity plants, which represent 30 percent of U.S. generation capacity and the largest source of power in our region, have remained the lowest-cost option. But they have become Public Enemy No. 1 for many environmentalists because they emit greenhouse gases, soot and mercury.

Many people are now advocating for wind, solar and nuclear power as the solution for the future because they don't generate soot or carbon dioxide. But unfortunately, the choice is not that easy, because not all else is equal.

First of all, how reliable would you like your power to be? Most people expect their lights to come on at night and their refrigerators to run all day long, but the sun shines only during the day and the wind doesn't blow all the time. Electricity can't be stored cost-effectively; it has to be produced continuously and in sufficient quantities so it's there when you want it. As a practical matter, that means wind and solar can never provide 100 percent of our electricity needs -- base load power will need to come from such sources as coal, gas and nuclear that can run continuously.

How much are you willing to pay? Higher electricity prices could cause serious problems for household budgets and for the competitiveness of many industries. The cost of solar power today (without federal subsidies) is about four times as much as traditional sources. Since the average household here spends about $900 per year on electricity, that means that if half of your electricity came from solar energy, it would cost you about $1,300 per year more. Wind power is much more affordable, but it still costs about 20 percent more than coal.

What are you willing to have in your back yard? Wind and solar power require a lot of land. To generate the same amount of electricity as a typical 1,000-megawatt coal or nuclear plant, you would need to build 200 windmills over a land area of 70 square miles (larger than the city of Pittsburgh), or 17 square miles of solar cells (the equivalent of covering almost all of Monroeville). If you put the solar cells or windmills "somewhere else," you'd need a lot of new transmission lines, increasing costs and reducing reliability, and that assumes there is "somewhere else" to put them -- recent efforts to site windmills in rural areas have run into significant public opposition.

What about nuclear power? It's a big economic development opportunity for Westinghouse and other businesses in our region, but there are constraints on nuclear energy's ability to become our primary source of electricity, including the rising cost of construction, U.S. dependence on foreign sources of enriched uranium, the lack of a place to dispose of the nuclear waste, and the small but still nonzero risk of nuclear accidents.

Although research is going on here and elsewhere to reduce the disadvantages of wind and solar power, even the most optimistic projections indicate that coal will remain the largest source of electricity for at least several decades. So rather than fighting it, we should work to make it cleaner.

New clean coal technologies have the ability to dramatically reduce soot and mercury emissions compared with older plants, while still keeping costs affordable. Moreover, our region could become a leader in reducing greenhouse gas emissions from coal, since we have the geologic structures needed for underground storage of carbon dioxide.

The right answer for our energy future -- and for southwestern Pennsylvania's economy -- is a balanced portfolio: more renewable energy sources than we have today, combined with cleaner coal.

For more insight on energy issues, visit 3RiversCleanEnergy.com.