Local view: Using coal cleanly, not renewables, is our only hope for future energy
Electricity is cool. I leave my air-conditioned office and the elevator whisks me down to my car. The last traffic light flashes green and I drive toward my air-conditioned house. Rolling up to the garage, I hit a button, the door opens and light...
Electricity is cool.
I leave my air-conditioned office and the elevator whisks me down to my car. The last traffic light flashes green and I drive toward my air-conditioned house. Rolling up to the garage, I hit a button, the door opens and lights go on. I soon smell dinner cooking in the electric oven. The TV remote brings up the evening news. During commercials, I read the News Tribune, printed earlier on big electrically powered presses.
We rarely think about all those electrons zipping along wires toward us from some power plant so they can do all that work. That plant burns something to make steam to drive turbines which turn generators to start the whole process.
Minnesota Power Company burns coal for more than 85 percent of the electric power capacity that serves 141,000 customers in Northeastern Minnesota. For the U.S. as a whole, the Energy Information Administration says that coal's share of electric energy is going to increase from 50 percent today to 57 percent by 2030.
The U.S. has a fourth of the world's coal reserves. But it's pretty dirty stuff, spewing out sulfur-based acid rain, carbon dioxide and millions of tons of coal ash full of mercury and sulfur. But what else is there for electric power?
Solar panels work OK on buildings in sunny climates, but they aren't practical for large power plants.
How about nuclear energy? It takes a 100-car hopper train with 10,000 tons of coal every day to feed a 1,000-megawatt coal plant. A 1,000-megawatt nuclear plant fissions just seven or eight pounds of uranium 235 and plutonium each day. But there are all those fission products in the spent fuel, radiating for thousands of years.
How about cleaner natural gas? Unfortunately, there's not enough of it, except for the imported liquefied stuff called LNG that can explode when regasified. And the Middle East is going to charge plenty for it.
Hydro is limited to a few locations, and oil is expensive and polluting.
The Minnesota Legislature is placing its alternative bet on wind power. The recently passed Renewable Energy Standard requires Xcel Energy to get 30 percent of its fuel from alternate sources, most of that from wind, by 2020. Wind supporters point to Denmark, which looks like a pin cushion with its 5,300 giant wind turbines. Denmark is widely reported to get 20 percent of its grid electricity from wind. But most of Denmark's wind power can't be used by its grid at the time it's generated. The actual contribution of wind to Denmark's grid is less than 7 percent.
More than 100 years ago, erratic wind was replaced by more-dependable coal, then oil, as a means to propel us across oceans. The same dependability is needed for electric power plants. A look at the State Wind Map reveals another wind problem for the Duluth area.
Northeastern Minnesota has the lowest average wind velocity in the state. The best winds are far off, on Buffalo Ridge, in the southwest, requiring long and expensive transmission lines.
A better bet is to burn coal through a process called Integrated Gasification Combined Cycle, or IGCC. Coal gasification allows chemical removal of mercury and sulfur, and the CO2 emerges as a separate stream which can be captured. The plant gets dual duty from the gases it produces. First, the coal gases, cleaned of impurities, are fired in a gas turbine -- much like natural gas -- to generate one source of electricity. The hot exhaust of the gas turbine is then used to generate steam for use in a more conventional steam turbine generator. The fuel efficiency is boosted by about 50 percent.
With Department of Energy support, Excelsior Energy is proposing to build the IGCC Mesaba Project, a 600-megawatt coal-fired plant on the Iron Range which will incorporate the latest gasification technology.
Sequestering the carbon dioxide will be a next step, but that delay should not block completing one of the world's cleanest and most efficient coal plants.
Coal replaced wood as our dominant energy source in the mid-1880s. It remained the leader until after World War II when oil and natural gas consumption began its sharp rise. But now, the energy wheel is bringing cheap, dirty and plentiful coal back into view as energy demand grows and production of oil and gas peaks. We have no choice but to learn to use it with the most efficient and clean process that technology can provide.
Rolf E. Westgard of Deerwood, Minn., is a professional member of the Geological Society of America, is a member of the American Association of Petroleum Geologists and is a regular speaker to civic groups on the subjects of peak oil and alternate energy.