MONROE - The U.S. Environmental Protection Agency's nationwide drive to reduce fossil fuel power plant emissions has brought about a remarkably complex and costly engineering and construction project that will make for a cleaner-burning and greener Monroe Power Plant.

The building trades, owner DTE Energy, engineer/constructor The Washington Group and Babcock Borsig Power are in the process of installing four SCRs (selective catalytic reducers) to reduce nitrous oxide pollutants next to the four boiler units of the 3,000-megawatt power plant. Construction began in 2000. The retrofit of the first unit is nearly complete, work on the second is ongoing, and the entire project is expected to be complete by May 1, 2004.

"To meet the requirements of the EPA, we needed a big-time reduction in NOx (nitrous oxide) emissions," said DTE Energy Project Manager Bill Terrasi. "We looked at 14 different technologies. The best solution we found was to put in the SCRs, but they're very expensive. And it's such a difficult project because we're trying to stuff this new equipment in a plant that wasn't designed for an easy retrofit.

"We've had engineers in from power plants around the country who have to install SCRs, and they tell us they're glad they're not us. This is probably the most difficult project of its type in the nation."

The $630 million price tag on the retrofit makes it the largest construction project for DTE since the Fermi 2 Nuclear Power Plant was completed in 1987. More than 600 construction workers are currently on the project, outnumbering the 450 DTE employees at the plant.

Completed in 1974, the coal-burning Monroe Power Plant is the largest power producer in DTE Energy's fleet and is the sixth largest in the nation. The plant is also the utility's largest emitter of nitrogen oxides, which can contribute to the formation of ground-level ozone. The EPA is requiring many power providers to reduce those emissions.

Selective catalytic reducers are part of a "post-combustion" system that treats furnace flue gas. As part of the process, diluted gaseous ammonia is injected into the gas stream ahead of the SCR. The nitrous oxide and ammonia react to form harmless molecular nitrogen.

The installation of the SCRs and improvements in their other plants will reduce NOx emissions by 65-70 percent company-wide during the warm-weather ozone season.
DTE Energy is spending more than $800 million to bring its plants in line with federal low-NOx standards.

"We've done enough sections where we've got a pretty good system going," said Dan Sadoski general foreman for Boilermakers Local 85 and the Washington Group. He was part of a crew installing a hood section atop one of the SCRs. "As we get more experience up here, it makes everything a little easier to figure out, but there's still a lot of hard work to be done. More than half of the rigging gang out here are apprentices, and they're doing a bang-up job. You couldn't ask for better workers."

Retrofitting the SCR units at the Monroe plant created a chain reaction of other tasks for the building trades. The design calls for portions of each SCR to be wedged in between the furnace outlet and the air heater inlet, while other SCR sections are being constructed above the existing boiler houses, reaching the height of an 11-story building.

The retrofitted SCRs and ducting made the flue gas throughout the system more meandering - meaning four heavier duty draft fans had to be installed, plus the associated duct work.

To support it all, each SCR unit at the Monroe plant requires the construction of more than 6,000 tons of structural steel. In more than 100 areas, the existing frame work of each of the boiler units had to be beefed up to accommodate the new equipment.

"We learned a lot from the first unit, and now we're building momentum," said Steve Miles, construction manager for The Washington Group. "We're installing this new technology in such a confined area, it's hard to get out of each other's way. But that's just the way the plant was built - it wasn't built for a retrofit."

The installation of the SCRs is all being done while all four of the plant's boilers remain in operation. Plans call for the SCRs to be started up during normally scheduled shutdowns.

Terrasi said well over one million man-hours will be spent on each of the four units - a number which would be reduced significantly if a power plant wasn't operating just a few feet away.

"Working on such a congested site, what the trades are doing here is very impressive," he said. "This project would go up in a heartbeat if we were building on a green field, but of course have to do it here. The trades are doing a fine job and we're fortunate to have them here."

THE RUST-COLORED HOOD section over the selective catalytic reducer under construction on Unit 1 is lowered into place at the Monroe Power Plant.

THIS CRANE at the Monroe Power Plant - the Manitowac 21,000 - is one of seven that are the largest in the world, and it will be operated by Frank Thomas of Local 324. The crane has a 640-foot boom and 1,000-ton lift capacity. The big capacity will allow the building trades to assemble more of the selective catalytic reducers on the ground.