Duke Energy’s announcement that it will shut down the last two coal-fired generators at the Buck Steam Station two years ahead of schedule is good news for the region’s air quality and a sign of evolving energy technologies.
In addition to being a major source of carbon dioxide — the primary greenhouse gas linked to global warming — coal-fired power plants release more toxic air pollutants such as arsenic and lead than any other U.S. industrial pollution source, according to the American Lung Association. These toxic substances not only pollute the air we breathe but can also enter the food chain through water and plants. That’s why the EPA, state regulators and environmental groups have pushed for stricter limits on coal-plant emissions.
The Buck plant, which at one time had six coal-fired units, began operation when Calvin Coolidge was in the White House. It was Duke’s first large-scale plant — a state-of-the-art station for a growing North Carolina. Now, that era’s aging coal-powered plants have become power-production dinosaurs incompatible with tighter regulatory controls and the emergence of cleaner, more efficient plants like the natural-gas combined-cycle unit that began operating at the Buck site a couple of years ago. Combined with upgraded grid technologies, the company says gas-powered plants promise fewer emissions and a more economical source of electricity for consumers.
Nationwide, greenhouse gas emissions from power plants fell 4.6 percent in 2011 as utilities burned less coal, the EPA reported Tuesday. Even with the shutdown of aging coal plants, however, there are environmental concerns about their residual legacy — the retention basins that hold millions of tons of leftover ash and the tainted groundwater under it. The disastrous 2008 spill in Tennessee raised awareness of the potential hazards of such ash basins and the need for longterm storage solutions.
State regulators and Duke officials are currently studying disposal options for the ash. One possible method is to pump out any water or liquid slurry and then cap the remaining dry ash. Another method, more costly but favored by environmental groups, would involve excavating the ash and hauling it to a disposal site safely removed from drinking water supplies. Whichever route Duke takes, the emphasis must be on protecting drinking-water supplies and ensuring these ash deposits won’t create future contamination issues.
Buck and the older generation of plants it represents supplied electricity for decades of industrial and residential growth in North Carolina. Now, we’re fortunate that cleaner technologies are available so that North Carolinians can enjoy the dual benefits of reliable energy and a healthier environment.