Bioenergy

What’s Up with Methane?

I’m a retired electrician and 30 years ago I did the instrument work on a coal to gas plant in Pittsburgh, Pa. It was nearly pollution free and made methane, which is very clean burning. Why after 30 years do I not hear more about this process? John S., Westbury, NY

John, Coal-fired power plants, which generate half of U.S. electricity, are responsible for 60% of U.S. sulfur dioxide emissions, 33% of U.S. mercury emissions, 25% of nitrogen oxide emissions, and more than 33% of the nation’s carbon dioxide air emissions. The Department of Energy (USDOE) and even some environmentalists have hung their hat on Integrated gasification combined cycle (IGCC) technologies to turn coal into hydrogen into electricity with low emissions of greenhouse gases. USDOE has had two IGCC plants in operation for several years: a 250-MW unit in Florida at Tampa Electric Power’s facility and a refurbished 300-MW unit at Cinergy’s Wabash River coal-fired power plant in Indiana. The Wabash plant is a rebuilt 50-year-old facility that reports an 82% reduction in NOx emissions and 97% fewer sulfur dioxide emissions. DOE also has other plants in the works, which is a big change for coal plants, where even clean ones produce a lake-sized impoundment of sulfuric slurry by pulling sulfur compounds from the stack flue gas. Currently IGCC plants are approaching a 40%+ thermal efficiency. One operating plant, whose high capital cost has been largely written off, is the Great Plains Synfuels Plant in North Dakota, where 6 million tons of lignite is gasified each year to produce clean synthetic natural gas. But emissions are in ‘the eye of the beholder’. Mountain tops are being blown off in West Virginia impacting land and water supply– and thousands of acres look like the moon in the southern part of the State. Other emissions such as mercury and other unregulated emissions (including radiation) can still have intensely adverse health and environmental impacts. There is no ‘free ride’ or ‘magic bullets’ using coal – the challenge is managing negative impacts as we transition to other cleaner energy options. A plethora of ideas abound such as pumping the carbon from coal into holes in the ground, but there is absolutely no proof that the carbon gases will not escape through fissures, earthquakes and platelet movements. The only coal resource that appears to have the most environmental benefits are coal bed methane, where the potent greenhouse gas is siphoned and used for energy before it enters the atmosphere. Best regards, Scott Sklar