Detroit Edison has consistently supported reasonable controls on power plant emissions and has been a leader in adopting new technologies and practices to reduce emissions.

In the last 30 years – while increasing generation output by about 53 percent – Detroit Edison has reduced emissions of nitrogen oxide and sulfur dioxide by about 60 percent across our electrical generating fleet.

In 1999, Detroit Edison launched a $1.7 billion program to install state-of-the-art emission controls at the Monroe Power Plant, the largest generating plant in DTE Energy’s system and the fourth largest coal-fired plant in the country.

The start-up of these emission controls marks a milestone in the history of the Monroe Power Plant and signals a new era of improved air quality in the region.

To view the various components of the new, improved Monroe Power Plant, click the image* at the right to enlarge it . 

Reducing NO_x

Selective catalytic reduction systems (SCRs) have been operational on three of the Monroe Power Plant’s four generating units since 2005. SCRs use a combination of metal catalysts and ammonia to convert nitrogen oxide (NOx) to harmless nitrogen and water.

SCRs provide a 90 percent reduction of NOx and help to reduce the formation of fine particulates.

Reducing SO₂

Two flue gas desulfurization systems (FGDs) have also been installed; the first will be operational in June 2009, and the second will be brought online in the fall of 2009.

FGDs are the global technology standard for controlling sulfur dioxide (SO2) emissions, which is an ingredient in acid rain. They work by routing plant exhaust through a shower of finely pulverized limestone in water. The SO2 bonds with the limestone, and after additional processing is ready to be sold as gypsum, an ingredient in wallboard.

The FGDs will reduce SO2 emissions by over 90 percent.

Reducing mercury and particulates

On units where both SCRs and FGDs have been installed, mercury emissions will be reduced by about 80 percent.  Other emissions in our exit gases will be lowered as a co-benefit of emission controls. 

A visible reminder

The FGD process produces a great deal of water vapor.  A new, 580-foot tall chimney – called a “stack” – was constructed for this new “wet” exhaust.

Instead of the former, barely-visible stack exhaust, there will be a constant, thick, billowy white plume emitted from the new, shorter stack. This plume consists primarily of water vapor released during the emission-control process, and is a noticeable reminder of the cleaner air produced with this new equipment.

Investing in Michigan

Construction of the new SCR and FGD equipment and the necessary support systems required over 9 million man-hours. 900 construction workers – carpenters, electricians, millwrights, welders, pipefitters and others – were employed at the height of construction. Over 40 permanent, full-time jobs were created to operate and maintain this equipment.

DTE Energy spent over $120 million with Michigan-based companies during this construction process.

Size and Scope

Construction of these new systems essentially doubled the size of the power plant but barely increased the footprint of the facility. Engineering, fabrication, and installation of these massive structures were complicated by the need to keep the power plant running during construction, and the need to build “up” rather than “out” because of existing buildings.

The SCRs alone required a 13-story structural skeleton using 7,000 tons of steel. We also opted to build a plant on site to convert urea into the ammonia needed for the SCRs, which eliminates potential health hazards associated with transporting and storing anhydrous ammonia.

Building the FGDs not only required construction of the new stack, but of several ancillary structures, including a limestone handling and transport system, wastewater treatment facility, and a gypsum dewatering system. Running all of this new equipment will consume about 15-18 MW, enough electricity to power 12,000 to 14,000 homes.

Looking to the future

In 2010, the first full year in which all the installed systems will be operating, the Monroe Power Plant will see emissions reductions of an estimated 70 percent for nitrogen oxide, 50 percent for sulfur dioxide and 40 percent for total mercury from 2000 levels.

Additional reductions will be realized in coming years with construction of the final two FGDs and the last SCR, which is tentatively scheduled to begin in 2010. The existing 800-foot stacks will also be removed.

A History of Environmental Stewardship

Since 1974, Monroe Power Plant has achieved significant reductions in annual emissions -- despite the fact that both coal use and generation output increased over the same period.

Monroe Power Plant is also proud of the following environmental achievements:

• Wildlife Habitat Council “Lands for Learning” site since 1999
• Certified to ISO 14001 in 2003
• Monroe County Corporate Citizen of the Year
• Designated a DEQ Clean Corporate Citizen in 2008
• State of Michigan Lotus Blossom Habitat

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