Treating wastewater so that it poses no threat to the environment is an energy-intensive task, but a Southern California water treatment agency has found a way to make the pollutants power their own removal. The Inland Empire Utilities Agency (IEUA), which treats wastewater in southwestern San Bernardino County, has just partnered with an energy firm to install the world's largest carbon-neutral fuel cell power station. The fuel cell will power IEUA's water recycling plant in Ontario with biogas, cutting its grid energy use while keeping powerful greenhouse gases and smog-forming chemicals out of the atmosphere.
IEUA's Regional Water Recycling Plant #1 just off the Pomona Freeway in the city of Ontario, built in 1948, treats 44 million gallons of wastewater a day from Ontario, Rancho Cucamonga, Upland, Montclair, Fontana, and outlying areas. The process of purifying wastewater is complex and energy-intensive. During that process, decomposition of organic solids in the wastewater results in the formation of gases like methane that are best not released to the atmosphere.
Some facilities will "flare" the biogas they produce to burn off the methane, but that creates problems of its own, namely the formation of smog precursor chemicals like oxides of nitrogen. But not burning the methane means it escapes to the atmosphere, where it acts as a greenhouse gas 25 times more powerful than carbon dioxide.
This week, though, a 2.8 megawatt fuel cell power plant built by Fuel Cell Energy Inc., and owned and operated by Anaergia Services came on-line at IEUA's Ontario plant. If all goes as planned the fuel cell will solve not only the plant's biogas problem but a few others as well. After having water vapor and sulfur contamination removed, the plant's biogas will be fed into the 2.8 megawatt fuel cell, where it will produce electrical power from the chemical energy held in the methane without burning it. Anaergia will sell the power to IEUA; the fuel cell is expected to produce around 60% of Water Recycling Plant #1's total demand. The fuel cell will release carbon dioxide to the atmosphere, but as that carbon came from biological sources -- namely San Bernardino County residents -- that carbon dioxide won't contribute to climate change, at least in theory. Avoiding combustion of the biogas means no smog precursors. And the heat generated by the fuel cell will be used to warm the plant's digester tanks, making the process of cleaning the wastewater all the more efficient.
And as Anaergia expects to pay for the fuel cell through a 20-year power purchase agreement with the utility, IEUA avoided most of the upfront costs that might have been involved in building their own plant.
"IEUA is proud to expand its already successful renewable energy program with the addition of a biogas powered fuel cell system" Terry Catlin, IEUA Board President, said in a press release. "The fuel cell allows IEUA to move closer to its strategic energy plan goal to go 'Gridless by 2020' with almost no capital outlay by the Agency," said Catlin. "Our plan is to minimize IEUA's dependency on energy purchased from the grid, and to be able to operate completely off the grid during peak energy usage periods."