LOTT to reuse gas for heating

Methane produced by plant will be converted to energy for new building

By John Dodge | The Olympian • Published October 12, 2008

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OLYMPIA – Methane gas generated at the LOTT Alliance wastewater treatment plant in Olympia will be converted into energy to heat the new administration and education building in the years ahead.

By the numbers

•Cost: $2.6 million; rebates will pay for up to 70 percent

•Energy output: 2.36 million kilowatt-hours — enough to power 250 homes.

•Savings: $190,000 a year in electricity and heating costs.

•Pollution reduction: 1,800 metric tons of carbon dioxide, 1,600 pounds of sulfur dioxide — the equivalent of taking 300 cars off of the road.

The Lacey, Olympia, Tumwater and Thurston County sewer partners have approved a $2.6 million contract to install a cogeneration system that will supply about 11 percent of the heat and electricity used at the LOTT complex at the foot of Budd Inlet, LOTT engineering director Brian Topolski said.

The energy output from the cogeneration project would be 2.36 million kilowatt-hours — enough to power about 250 average-size homes, Topolski said.

Currently, the sewer utility burns off much of the methane gas it produces in the treatment plant process to no benefit — except for its eternal flame.

The new system, which consists of gas dewatering equipment, a 335 kilowatt engine and two natural gas boilers, will save the utility about $190,000 a year in electricity and heating costs. The project should pay for itself in about six years, thanks to project rebates from Puget Sound Energy estimated at 50 percent to 70 percent of the total cost.

The cogeneration plant also will reduce greenhouse gas emissions from the LOTT complex, including 1,800 metric tons of carbon dioxide and more than 1,600 pounds of sulfur dioxide, project officials said.

"It's the equivalent of taking about 300 cars off the road," Topolski said.

LOTT officials have considered building a new cogeneration plant for years but were wary of investing in such a project because of the spotty performance and high maintenance costs of similar plants at other facilities, Topolski said.

But new technology and better performing engines installed at wastewater treatment plants in Eugene, Gresham and Portland, Ore., persuaded them to move forward.

The LOTT contract, with TRANE Inc. of Kirkland, calls on the state Department of General Administration, which has experience with cogeneration projects, to manage the project.

The energy-producing plant is expected to be operating in about 15 months, Topolski said.