By Anna Lynn Spitzer
Irvine, Ca, May 17th, 2013 -- The concept seems a contradiction of the highest order: using raw sewage to make the planet cleaner?
It’s true. At the Orange County Sanitation District in Fountain Valley, Calif., methane and other biogases are produced by sewage as it sits in concrete holding tanks. These are fed into a stationary fuel cell, which converts them into electricity and heat to run the facility, and hydrogen to fuel the next-generation of fuel cell vehicles.
Imagine: all those cars sitting bumper-to-bumper on the freeway could be getting the equivalent of 70 miles per gallon without spewing anything more harmful than water into the atmosphere, courtesy of humanity’s perpetual stream of waste.
The wastewater-to-fuel idea is the brainchild of Scott Samuelsen and Jack Brouwer from UC Irvine’s National Fuel Cell Research Center. They figured out how to make fuel cells tri-generate – that is, produce hydrogen fuel at the same time they generate power and heat.“Renewable fuels will be required for sustainable transportation in the future. This method of converting waste gas into a transportation fuel is one of the most efficient and environmentally sensitive methods there is,” Brouwer says.
The NFCRC partnered on the prototype with the Orange County Sanitation District; FuelCell Energy Inc., which manufactures ultra-clean stationary fuel cell power plants; and Air Products, a supplier of hydrogen and other industrial gases.
The first hydrogen-fueled cars pulled up to the pump at the OC Sanitation District a year-and-a-half ago; today, the facility produces about 120 kilograms of fuel per day, enough to fill the tanks of about 30 cars.
“The project is going extremely well,” says Samuelsen, NFCRC director. He cites integrated operation and performance, extension of the technology to new applications and continuing awareness from all corners of the world. “This is the epitome of sustainability.”At the OCSD, where 207 million gallons of sewage are treated daily and 98 percent of solid waste residuals is recycled, bacteria in large digesters break down the sewage, releasing the methane and other bio-gases. These pass through a pre-treatment system before flowing into the fuel cell, where they combine with heat and steam to produce hydrogen.
The fuel cell uses an electrochemical reaction to generate electricity and heat – used to run the plant – from the hydrogen. The process produces more heat and steam, which, when combined with the treated gases, generates still more hydrogen. The residual hydrogen then is purified, compressed and dispensed into fuel cell vehicles at the on-site filling station.
The amounts of electricity, heat and hydrogen produced by the fuel cell can be adjusted to meet demand. “The great thing about this technology is that you don’t have any stranded assets,” says Ed Torres, OCSD director of operations and management. “You dial up the hydrogen production when you have the demand from the vehicles and when you don’t, you just dial up the electricity to power the plant.”
The model is the world's first but many more are expected to follow. Stationary fuel cells are already installed at many wastewater treatment plants to generate electricity and heat, and he says they can be modified to produce hydrogen fuel as well.
Fuel cells are also in use at other manufacturing facilities. Gills Onions in Oxnard, for example, uses two 300-kilowatt fuel cells to convert up to 300,000 pounds of onion waste daily into renewable energy to power its processing plant. “They could easily produce hydrogen – and they very well may one day – because the system is retrofittable,” Samuelsen says.
Hydrogen-fueled vehicles offer consumers a long list of benefits. Besides supplying three times the mileage, dollar for dollar, of their gasoline-fueled predecessors, they are quieter, more responsive and free of hydrocarbon emissions.
The domestic production of hydrogen fuel is a plus, too. “You can almost feel that our petroleum future is very shaky and it wouldn’t take much to dramatically change our access,” Samuelsen says.
There are approximately 100 hydrogen-fueled vehicles in Southern California, all of which are leased to drivers by the car manufacturers, and there are just a handful of filling stations. But automobile makers including Honda, Toyota, General Motors, Mercedes and Hyundai are gearing up to sell the cars within the next few years, and a hydrogen infrastructure of 68 stations is expected throughout the state by 2015 to meet the demand.
Several gasoline stations in Orange County are being modified to include hydrogen pumps, and many more are on the drawing board.
With the exception of the one at OCSD, all the stations currently dispense hydrogen fuel made from natural gas. The state, however, is requiring that a minimum of 33 percent of all hydrogen fuel sold in California must come from renewable sources so Samuelsen says “it’s a good bet” that many of the new stations that come online will pump hydrogen generated through a sewage waste system like the one at OCSD.
And instead of trucking hydrogen in from a central production facility, he believes the future holds many miles of underground hydrogen pipeline that will carry the fuel from production and waste disposal facilities. Additionally, researchers are looking at ways to process the substantial quantity of biogas from landfills, the composition of which is a little more complex than that from wastewater.
“This technology is remarkably efficient … and extremely clean and quiet,” Brouwer says. “It can be applied to produce hydrogen, power and heat locally from almost any available hydrocarbon gas at the point of need, which can also avert the energy and emissions penalties of fuel transportation.”
“The future is wide open,” Samuelsen says. “When you have a reliable supply of biogas there are no impediments to producing renewable hydrogen fuel.”
As for the pilot project, Torres says officials are open to seeing the prototype – or a larger system – permanently adopted at Orange County Sanitation when the three-year demonstration concludes. “We have an environmental stewardship viewpoint and we would definitely like to continue to participate if it’s in the best interests of the sanitation district and the ratepayers we serve,” he says.