Bio-gas / Poop to Power

By Don MacGillivray

Portland will soon be processing the City’s sewage and making a profit doing it. This is making “power from poop.” With over seven billion of us on the planet and all of us creating waste on a daily basis, there is a lot of potential in making it pay. And now, this Oregon city has found a way to do just that.

Every year, the Portland Bureau of Environmental Services processes 28 billion gallons of wastewater. Methane is a potent greenhouse gas that is a natural byproduct of sewage treatment process. This summer, the Bureau of Environmental Services will begin an innovative effort that will capture 100 percent of the methane gas from our waste water which will significantly reduce our carbon footprint. It will convert this smelly, unattractive waste product that we all produce into a valuable, renewable natural gas that can be sold on the open market.

This will be Portland’s single largest climate action project. This clean, locally-produced fuel will be distributed in Portland and elsewhere with the help of the NW Natural Gas network. The project will:

Cut greenhouse gas emissions by 21,000 tons annually,

Generate between $10 and $3 million in revenue a year for the City thereby reducing sewer costs, and replace1.34 million gallons of dirty diesel fuel with clean Renewable Natural Gas which will fuel 154 garbage trucks for a year.

The resulting methane gas will become a Renewable Natural Gas gas that will be used to power vehicles. Because this product is a renewable fuel and not a fossil fuel, it commands from five-to-ten times the price of the other products on the renewable energy market.

For years, the City has been capturing a portion of this methane gas to produce electricity. Seventy-seven percent of the city’s methane is already being re-purposed at the city’s wastewater treatment plants. Currently about half of the plant’s waste methane is already reclaimed to heat and power the treatment plant. The remaining 23 percent of the 600 million cubic feet of methane, bio-gas, produced by anaerobic digesters is burned off in a process called “flaring” where it becomes carbon dioxide which is another potent greenhouse gas when released into the atmosphere. This proposed project would eliminate flaring and convert all the methane into reusable gas. Some of this energy is used onsite for heat and to produce electricity, and some is sold to Malarkey Roofing Company for use in their manufacturing process.

This project will allow the City to recover 100 percent of its methane and end the regular flaring of it in the open atmosphere. By increasing revenue, addressing climate change, and providing cleaner air this project is a triple-win for the City of Portland. The Oregon’s residential ratepayer watchdog, the Citizen’s Utility Board, has endorsed this project as an example of good environmental stewardship for others to emulate.

A compressed natural gas fueling station will be built and finished by the end of this year at the Columbia Boulevard Wastewater Treatment Plant where the methane will be sent to Northwest Natural Gas. The $12 million in construction costs will be paid back within about four years. Renewable Natural Gas is the lowest-carbon fuel option for medium and heavy-duty vehicles. Large trucks with new natural gas engines can produce 90% fewer nitrous oxide emissions compared to the cleanest diesel engine. By using Renewable Natural Gas, that same truck’s greenhouse gas emissions can drop by 80 percent below diesel.

Portland also uses the solids portion of the waste to make an organic fertilizer that is used in commercial farming. This includes an extensive process to insure that the product is free from heavy metals and various organic compounds. It meets the standards set by the Oregon Department of Environmental Quality and the U. S. Environmental Protection Agency. So the Portlanders who pay their water-sewer bill every year are actually going to see a return that will allow the utility costs to become more stable,

The positive reuse of Portland’s sewage is one example of an environmental solution that can, if copied, help to change the world and it has the benefit of paying for itself. American businesses are finding many ways to address the challenge of climate change, from innovative electric cars to state-of-the-art solar manufacturing. These proven technologies will transition the United States to 100 percent clean and renewable energy by 2050 while also creating millions of jobs if we have the will to do so.

Oregon Senator Jeff Merkley has introduced a new bill called the “100 by ’50 Act” that will build on these facts. It will advance the bold policies that are necessary to deploy these technologies rapidly and cost-effectively. The bill lays out how to move to 100% clean and renewable energy while ensuring an equitable transition for workers in low-income and disadvantaged communities.

The scientific community knows the devastating impacts of climate change must be addressed. This bill will encourage local governments, businesses, and communities to develop their own plans to use 100 percent clean and renewable energy by 2050. This builds on the work in Portland and Oregon to solve these challenges.

This sewage recycling project is a key step in the pledge made by Mayor Ted Wheeler to obtain 100 percent of Portland’s energy from renewable sources by 2050. In 2009 the City adopted the “Climate Action Plan” and is well on the way toward its implementation. There will be very real challenges, but the future of our nation and the world is at stake.

Bio-gas / Poop to Power

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