To meet new air quality regulations, Riverside, Calif., will soon convert waste biogas into renewable power in a way that's virtually absent of pollutants that cause smog and acid rain.
Governments exist to do the things that no one else wants to, like figuring out what to do with a community’s wastewater. In Riverside, Calif., wastewater is managed at the Wastewater Quality Control Plant, and a byproduct of the material found there is a steady stream of biogas -- some of which is used to power the facility’s internal combustion engines, and some of which is burned on a flare and released into Earth’s atmosphere. But using a 1.4 megawatt fuel cell, the city will soon have a cleaner way.
In April, the city’s public works department proposed the purchase of the fuel cell, and in mid-May came the announcement of a 20-year agreement between the city and Riverside Fuel Cell in which the city will divert its excess biogas to an onsite carbon-neutral fuel cell that will power about half of the plant’s operations at no cost.
Under the agreement, the city pays Riverside Fuel Cell only for the power it needs for its operations, and at a rate marginally lower than what was previously paid for power to the electric company. Riverside Fuel Cell will pay for and manage the installation, operation and maintenance of the equipment.
It’s a good deal for the city, said Ernest Marquez, principal engineer for Riverside, because the South Coast Air Quality Management District will impose new rules in 2016 that would have prevented them from continuing to waste biogas as they have been doing for years.
And with the plant’s internal combustion engines failing, meeting the requirements of the upcoming regulations would have saddled the city with $4 million in required equipment upgrades. Pursuing a fuel cell solution, though, enabled the city to pursue about $6.5 million in grant funding through the Self-Generation Incentive Program, a state fund that encourages energy systems like wind, heat and advanced energy storage systems, and funding from the district itself.
The project, which is scheduled for construction from April to September of 2016, represents just one of a few such fuel cell projects in American government. Private-sector organizations like Verizon and the First National Bank of Omaha have invested in fuel cell storage in recent years, sometimes to the tune of tens of millions of dollars. And deployments in California, Connecticut and New York (the big three fuel cell states) indicate an upward trend, but few public-sector examples exist. Marquez noted similar projects in Ontario, Canada, and another in a neighboring California city, but said he knew of few others.
Riverside itself is an early adopter, not for its upcoming project, but for its existing fuel cell technology, installed in 2008, which Marquez said has now become too inefficient to use.
“That facility ran through its course, and that was something that the city put in itself,” Marquez said. “That was their first-run technology. The facility ran its course because about every five years, you need a new fuel stack.”
Another problem with the city’s first approach to fuel cell technology was the need for a gas cleanup skid, a piece of equipment that removes contaminants from the gas before it can be used in a fuel cell. The city engineered its own skid for the past project, Marquez said, but that also stopped working well. This time, Riverside Fuel Cell is engineering and maintaining everything, so all the city has to do is pay for the energy.
In fact, Marquez said, one of the things he learned on this project was that it’s best to let everyone stick to the things they’re good at. The public works department relied on experts from the public utilities department to negotiate the contract, because that was something they were good at.
“We’re in the sewage business,” Marquez said. “We’re not really in the power business. But they do have experts on board that helped negotiate the contract, so we kept their experts in that department to help us negotiate, and that was a big plus for the city.”
Using biogas to harness green energy and power half of the plant’s energy needs is good, Marquez said, but they can’t use biogas to get all their power because there just isn’t enough gas. However, the plant is also now in the middle of a $200 million expansion project that will bring two new digesters to the facility that will in turn create more biogas, which the city can later decide to harness with more fuel cells if it’s deemed financially and procedurally practical.
“We don’t want to just burn it off through the air, we want to use it,” Marquez said. “This would be wasted and producing greenhouse gases. Now we’re putting it to work.”