DTE Energy has Cleanest Coal-Fired Plant

Michigan's DTE Energy, one of the state's largest utility companies, finished a massive 14-year retrofit of its Monroe Power Plant in mid-October. Instead of emitting poison gases such as mercury, nitrogen oixide and sulfur dioxide, the coal-fired power plant now sends mostly water vapor into the atmosphere. The plant bills itself as one of the cleanest of such facilities in the country.

The Monroe Power Plant's clean energy initiative started in 2000 and cost DTE Energy as much as $2 billion over the entire course of the project. The original coal-fired power plant was not designed to have gas-capturing aspects added to it. The facility doubled its acreage, added four 14-story selective catalytic reduction units and four flue gas desulfurization units. The SCR machinery removes 90 percent of nitrogen oxide emissions, whereas the FGD units take out 97 percent of sulfur dioxide and other acidic gases before they reach the atmosphere. Together, these aspects of the plant prevent 80 percent of the coal's gaseous mercury from escaping.

When the products of coal combustion escape into the catalytic converter units, the toxins are removed in a process that features several sieve-like compartments. Ammonia gas splits nitrogen oxide molecules into nitrogen and water. The coal-fired power plant retrofit then uses an electrostatic precipitator, which contains electrified wires, to remove fly ash and 99.9 percent of particulate matter from the emissions. The final part of the process sprays limestone powder and water onto the gas to neutralize sulfur dioxide.

Products of these catalytic processes are saved and recycled for use inside and outside the coal-fired power plant. After the air goes through SCR units, an air pre-heater shunts heat back into the boiler to conserve energy. Fly ash is turned into a filler for concrete. Limestone, sulfur and water combine to form gypsum, which is the main ingredient of drywall used in home construction. Gypsum from the plant began exporting to Canada in August 2014.

The Monroe Power Plant is the largest coal-fired power plant in Michigan and the fifth-largest in the United States. The project was a boon to the local economy, adding more than 900 skilled jobs at peak construction. The retrofit marked the continued dedication of DTE Energy's move to diversify its products for Michigan's power needs. DTE Energy has several other clean energy initiatives that include sustainable energy, natural gas and energy efficiency projects.

DTE Energy claims these emission reduction portions of the Monroe Power Plant are world-class. With possible future changes in energy policy to reduce global warming, DTE Energy can coach other utility companies about how to reduce harmful emissions. Energy companies may find it hard to move away from coal since prices of the commodity have dropped due to inexpensive natural gas prices. When more utilities went to natural gas, demand for coal plummeted, and coal now costs less than natural gas. Perhaps more energy companies may catalyze coal emissions thanks to DTE Energy's successful transition and very low coal prices.

The number of coal-fired power plants may be shrinking as more energy alternatives become less expensive. However, Michigan's DTE Energy discovered a way to help keep global warming at bay while maintaining the coal industry and helping the local economy thanks to a clean air initiative that benefits everyone.

Photo courtesy of John Kasawa at FreeDigitalPhotos.net