Where It Comes From, Where It Goes


Energy for Electricity Is Not the Same as for Transportation
At a recent party, a young man claimed that we needed wind power to avoid fighting a war in the Middle East. This is mistaken. Wind power generates electricity, while the Mideast is a source of oil used to drive cars. They’re not the same thing.

Transportation is powered largely by oil while electrical energy comes mostly from coal, some from nuclear, and a small percentage from such renewable sources as hydro, wind and solar. There is some overlap—electricity runs metropolitan and commuter trains, while about 1% of our electricity is generated by petroleum.

Renewable energy will thus do nothing to reduce our dependence on oil unless we can greatly increase our use of electric cars. Currently, the number of electric cars in the U.S. is effectively 0%, although it’s expected to increase rapidly. Those few electric cars on the road depend on an energy grid largely powered by coal, but because electric engines are up to 80% efficient, while gas engines are only 30% efficient, greenhouse gas emissions are reduced. The real benefits will come if we can get a higher percentage of the grid powered by renewable energy—which should be technologically achievable—in combination with a large number of electric cars.

Electric Cars and Other Alternatives

Every major car company has introduced, or is working on, electric cars, and President Obama has called for one million electric cars on the road in the next four years. Yet with a total automobile fleet of 246 million, one million vehicles is negligible, important mainly for what it shows about a potential oil-free future. Another technological problem is the cost of electric car batteries, currently around $10,000, although expected to come down rapidly.

Biofuels, the other alternative to oil, can only be considered renewable if they are harvested sustainability (in which case they are largely a form of solar energy, as they take and store energy from the sun). Many environmentalists consider corn ethanol a boondoggle, as it relies on oil-intensive cultivation methods. Sugar cane is far more energy-efficient—and has freed Brazil from oil imports—but care must be taken that its cultivation doesn’t lead to the razing of rain forests. Algae might be our best hope for a biofuel that replaces oil, but technical problems mean that it’s not yet ready for mass production.

As I pointed out in my February 9 post, electrical generation could become entirely renewable through a combination of solar—including large solar thermal plants; wind—including major installations and transmission grids off the coast; geothermal; and hydro (ocean wave energy is also under development). To end our oil dependence is a different problem, depending on continuing advances in battery technology and/or a breakthrough in our use of biofuels. Understanding how the two differ will help us debate and decide more wisely.