Ameren Missouri customers will see a rate increase as the utility provider works to filter emissions and abide by environmental standards.

The average residential ratepayer will see their utility bill go up about 8 dollars a month, says Public Service Chairman Kevin Gunn. The cost is to install scrubbers, air filtration systems that remove more than 95 percent of a plant’s sulfur dioxide emissions.

The Sioux Plant near St. Louis is one that will benefit from the new filtration systems, resulting in cleaner burning energy.

However, Gunn says the PSC denied Ameren’s request to charge customers for work on the Taum Sauk reservoir. He says the Taum Sauk reservoir failed in 2005 due to faulty construction and equipment on Ameren’s part, and the company agreed then to hold ratepayers harmless in rebuilding. In they plan submitted, he says, commissioners had a hard time differentiating between reconstruction and enhancements, so they denied that request.

Ameren Missouri utility customers will pay about $8 a month more each month when a recently approved rate hike goes into effect. That will help pay for the $172 million Ameren Missouri is recouping for the filtration systems.

The commission approved the increase and denied the Taum Sauk enhancement costs on a 5-0 vote. Gunn says enhancements only would qualify for a rate hike, but because it was unclear if they were true enhancements, not part of the rebuild, the commission said “no.”

AUDIO: Jessica Machetta reports [Mp3, 1:17 min.]

The Taum Sauk resevoir overflowed and collapsed in December of 2005, sending a deluge of water down a mountain in Southeast Missouri.

Opposing the increase are members of the Fair Energy Rate Action Fund.

“This rate increase will make it that much harder for Missouri families and businesses to recover from this economic downturn,” the group said in a press release. “This ruling shows precisely why consumers need to have a greater voice in the ratemaking process moving forward. Our coalition will continue to lead the fight to protect a balanced ratemaking process that will hopefully produce stable, low -cost rates for Missourians. While the overall ruling by the PSC will have serious economic ramifications for Missouri, the commission should be commended for rejecting Ameren’s bid to have ratepayers pay for the cost of rebuilding the Taum Sauk reservoir. After four rate increases in the past four years it is now incumbent on Ameren to become more efficient at a time when Missouri families and businesses can least afford future rate hikes.”

Gunn says this increase is indicative of the cost of compliance … as environmental standards increase, so will the cost of electricity for states like Missouri that rely on coal for energy.

Ameren’s Sioux Plant Scrubbers…

Ameren says the clean-air filtration system — scrubbers — like the one at the Sioux Power Plant, are air filtration systems that remove more than 95 percent of a plant’s sulfur dioxide emissions.

As hot flu gas passes through each scrubber, a slurry of crushed limestone and water is sprayed into it. The limestone in the slurry reacts with sulfur in the flu gas, creating synthetic gypsum – an inert material that will be captured and stored in a new landfill on plant property. Gypsum is the main component of wallboard.

The new stack consists of two separate liners, one for each of the plant’s generating units. A white plume of water vapor is visible from the plant whenever it is generating electricity. The two original stacks will no longer be used.

The Sioux plant is in St. Charles County, Mo., 28 miles northeast of downtown St. Louis. It was built in 1968.The plant typically burns around 3 million tons of coal annually.