Thursday, October 3, 2019

From Puget Sound curbside pickup to biofuel energy

Klickitat PUD harnessing landfill emissions as renewable natural gas

Roosevelt Regional Landfill in Klickitat County is the largest in Washington State

ROOSEVELT -- Along the eastern border of Klickitat County in arid south Central Washington, there resides the Roosevelt Regional Landfill, one of the largest landfills in the United States.

In volume, Roosevelt dwarfs the landfill on the Hanford Reservation near the Tri-Cities, where nuclear waste was dumped and stored during the Cold War. Roosevelt is permitted to hold as much as 120 million tons of solid waste on 2,500 acres (as opposed to the 20 million-ton capacity at Hanford)

Every day, trains deliver 300 containers of trash and garbage to the Roosevelt landfill. Most of it comes from the millions of people living along the Puget Sound corridor, traveling from Bellingham, through Everett, Seattle, Tacoma, and Olympia, along the shores of the Columbia River, before being deposited at a cavernous final resting place.

Only things are never entirely at rest.

300 containers of garbage arrive daily

Putting chemistry to work

When garbage decomposes in an oxygen-free environment, methane gas is produced, the primary component of natural gas. At many landfills, methane and a potpourri of other gases are "flared off," creating carbon dioxide and water. While this is better than releasing the gases directly to the atmosphere, it does not take advantage of methane’s power-producing potential.

Methane is 30 times more harmful as a greenhouse gas than carbon dioxide, so harnessing that gas in a good way just makes sense.

For the last 20 years, Klickitat County Public Utility District (PUD), and the landfill’s owner, Republic Services, tapped into landfill methane to generate electricity for PUD customers.

Now, in a new initiative, they are purifying the landfill methane as renewable low-carbon vehicle fuel, fed to a nearby natural gas pipeline. As the PUD and Republic have pursued these green-energy projects, our Ecology air quality engineers have been by their sides, making sure their projects meet and surpass air quality standards.

A ribbon-cutting affair

In September, Gov. Jay Inslee and local Sen. Curtis King, R-Yakima, christened the new H.W. Hill Renewable Natural Gas facility operated by the PUD as one of the largest and most efficient in the United States.

Inslee applauded the PUD and landfill operators as pioneers in Washington's clean-energy future, calling the project “a remarkable story of vision, perseverance and chemistry.”

"I’m happy to be in Roosevelt celebrating the next step of the clean energy transition,” the governor said on Twitter. “Methane from one of Washington's largest landfills will be transformed and readied for use as a low-carbon transportation fuel that reduces greenhouse gas emissions from vehicles on the West Coast."

What makes this renewable energy?

Natural gas derived from decomposing organic matter is considered renewable, compared to fossil fuel extracted from non-renewable sources.

"The waste material picked up at curbsides, dropped at transfer stations or sent by rail to the Roosevelt Landfill becomes a feedstock for biogas creation,” Klickitat PUD said in an overview of the project. “The biogas injected into the nearby Williams Northwest Pipeline is 98 percent pure methane and is used as transportation fuel throughout the country."

Air Permit History

Over the years, Ecology's Air Quality Program has worked closely with both the PUD and landfill to achieve the goals of these unique renewable energy projects. In 1998, the PUD began operating five internal combustion engines to generate electricity from landfill gas. In tandem, Air Quality Engineer Lynnette Haller developed a permit on how to manage emissions to meet the green energy standards of the day.

In 2008, the PUD used landfill gas to power turbines generating electricity, becoming the largest landfill gas power plant west of the Mississippi. Again, we worked with them on emissions permitting at the PUD plant and at the landfill.

Today, the PUD has ceased electric power production using methane, and is now cleaning the landfill gas for injection into the Williams natural gas pipeline to be used as biogas. The new operation provides an alternate revenue source for Klickitat PUD, allowing it to diversify and provide customers stable utility rates.

In addition, because they are no longer burning the gas onsite to generate electricity, the facility’s potential to emit air pollution has significantly dropped. So much so that we were able to rescind their federal Title V Air Operating Permit, an unusual accomplishment for a large operation.

In fact, the new renewable energy facility now qualifies as a minor source of emissions and the PUD is able to pay lower annual fees and require less oversight. A truly monumental achievement!

Central Region Director Sage Park joins Air Quality engineer Lynnette Haller at the new biogas facility ribbon cutting

By the numbers

Another unique technological innovation employed at the landfill is a process called cryogenic nitrogen removal -- used to extract contaminants and purify the methane.

In a process that separates nitrogen from the methane, the methane is recycled through and used as its own refrigerant. This reduces the facility’s electrical load for cooling, saving up to 16 million kilowatt-hours of electricity per year!

Now that it is fully operational, the renewable natural gas project is producing the equivalent of 15 million gallons of gasoline per year, made available as renewable transportation fuel. Initial sales are to California, reducing greenhouse gas emissions from vehicles on the West Coast.

Other factoids:
  • For 20 of its 30-year history, natural gas from the landfill has been put to beneficial use, reducing emissions to the atmosphere and generating, clean green power.
  • 300 containers per day of municipal solid waste are received at Roosevelt Regional Landfill from five Western U.S. states and British Columbia
  • 11.5 million cubic feet per day of landfill gas can be processed at the landfill for renewable energy
  • 15-plus million gallons of gasoline equivalency produced each year as renewable biogas

By Joye Redfield-Wilder, Central Regional Communications Manager

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