Budd Inlet Plant Cogeneration System Uses Methane for Heat, Energy

A new cogeneration system installed at the Budd Inlet Treatment Plant by the Lacey, Olympia, Tumwater, and Thurston County (LOTT) Alliance has reduced the amount of energy needed for treatment processes and buildings at the plant by using treatment by-products as fuel.

This renewable energy system, combined with an aeration blower retrofit currently under way at the Budd Inlet Treatment Plant in Olympia, Wash., is expected to save more than $228,000 per year in utility costs.

Leaders at the LOTT Alliance received the Trane "Energy Efficiency Leader Award" for their sustainable energy and operational efficiency improvements.

Puget Sound Energy (PSE) provided a $1.7 million Energy Conservation Grant to install the cogeneration system. PSE is Washington state’s oldest and largest energy utility, with a 6,000-square-mile service area stretching across 11 counties. It serves more than 1 million electric customers and nearly 750,000 natural gas customers. The grant represents 70 percent of an estimated total project cost of $2.4 million for the cogeneration system project. The estimated PSE grant for the aeration blower upgrade is more than $300,000, which represents 70 percent of the total project cost. The combined projects are expected to result in an energy savings of more than 2.8 million kilowatt-hours (kWh) per year, enough to power more than 210 Thurston County homes.

LOTT’s cogeneration system converts methane gas to heat and energy for use in LOTT’s Regional Services Center, which will be completed in July, and for future use in the new Hands On Children’s Museum, which will be located next to the plant. The Regional Services Center houses the Water Education and Technology (WET) Center, an educational center for ages 10 and older, a water quality laboratory, and offices. The new museum, scheduled to break ground this summer, is an independent non-profit organization that provides interactive educational experiences.

The cogeneration system, expected to save nearly $180,000 a year in utility costs, enables the cogeneration plant to provide all of the heating required at the site as a "district heating" plant, eliminating the need to burn off excess digester gas and greatly reducing the emissions of the site. The blower retrofit, scheduled for completion in August, is expected to save more than $48,000 in utility costs for the LOTT Alliance. As an innovative, renewable energy technology, the cogeneration system supports plans to earn LEED certification for the center and the museum.

A Washington State Department of General Administration Energy Performance Contract was used to procure services associated with the design and installation of the two projects. An option that provides a method for organizations to manage and optimize their energy use, a performance contract, allows them to leverage the energy use and operational savings to support strategic business objectives.

"As a public wastewater treatment facility, responsible use of community resources represents the core of our work," said Doug Mah, president of the LOTT Alliance board of directors and mayor of Olympia. "We’re pleased that we can further our commitment to environmental stewardship with these improvements and that these upgrades will also benefit our new neighbors at the museum. Even better, we’ll achieve it all with minimal costs to the utility."

LOTT staff considered several technologies prior to selecting the blower retrofit and cogeneration system. They conducted a thorough evaluation of several energy conservation upgrades and, based on the findings, selected the two that best met their needs. Staff chose the cogeneration system because it is expected to produce the most usable energy per pound of carbon dioxide released in comparison to the other alternatives studied. Employing the cogeneration process includes adherence to strict emissions standards as well as combusting approximately 99.9 percent of the methane, dramatically reducing LOTT’s greenhouse gas emissions.

The aeration blower retrofit will replace one of the large existing blowers with a smaller, high-efficiency, high-speed turbine blower. The new blower will become the primary operating unit, serving approximately 95 percent of the plant’s aeration system needs.

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