Methane digesters are shutting down due to new environmental regulations. How will the controversy impact clean fuel projects in Santa Cruz?
Despite the 1,700 cows roaming the Fiscalini Farms barn, things are surprisingly quiet.
“Happy cows don’t moo too often, and these cows live in the lap of luxury,” says Nettie Drake, an agricultural engineer who helps dairies install renewable biogas systems.
Nestled among the rolling grasslands of Modesto, Calif., the state-of-the-art open-air barn offers rock salt, handmade cow beds and a flexible milking policy. But the cows produce a lot more than milk: about 8,000 gallons of manure is rinsed from the barn floor three times every day. With each rinse, a river of water floods the cement floor, carrying waste to a biogas digester. Here, naturally occurring bacteria break down the sludge, releasing methane.
Normally a clean-burning generator converts the biogas to electricity, making enough to continuously power 600 local homes, and bring in $100,000 a month if the power is sold back to the grid. But today the Fiscalini Farm bright orange caterpillar engine sits in a shed, silenced by a series of new Air District policies.
In January 2009 the San Joaquin Air District passed a rule requiring digester projects to cut emissions by up to 80 percent. Most new projects will have to install a selective catalytic converter, a honeycomb-shaped filter that removes a particulate pollutant linked to asthma. Sacramento and South Coast air districts have recently adopted the same standards, and Santa Cruz may eventually follow suit.
Farmers, water treatment plants and engine manufacturers say the requirement is unrealistic. Not only does the converter cost $10,000 to $50,000, but it burns out often and must be replaced. Three dairy digesters have closed indefinitely because they can’t afford the upgrade. Another three are stuck in the permitting phase, and eight others have abandoned plans for construction because their designs can’t meet standards.
The rules may be the first in the nation to pit air pollution concerns against climate change efforts, demonstrating the need for new energy policies that evaluate electricity sources according to net environmental impacts.
Methane Power Causes a Stink
Dairy farmer Ron Koetsier shut down his digester before the rule changes went into effect. “If the regulatory hurdle hadn’t popped up we would still be up and running, but at this rate we will never make a profit,” says Koetsier. His $1.5 million system needs $150,000 in upgrades if it is to meet new standards.
The biogas generator at the Atwater, Calf.-based Gallo Dairy also lies torn apart. On the other side of the corrals, black plastic bubbles up over a seven-acre manure pond. The methane will ultimately go to waste, at least until manager Carl Morris replaces his eighth catalytic converter.
A crewman tinkers with the piping, and Morris points to a singed metal plate. “This thinner one didn’t fit well,” he says. “The problem is that no one has ever done this combination—a catalytic converter on a caterpillar engine powered by biogas with emissions this low. If there is any instability in the system—if the exhaust goes too hot or too lean—then boom, you are out of compliance or the converter burns up.”
Dave Warner, who helped guide the rule changes at the Fresno-based San Joaquin Valley Air Pollution Control District, admits the required parts aren’t designed for dairies. “[The rule is] intended to force new technologies … and we understand the nature of the fuel and the equipment well enough to make this requirement,” he says. Alternative pollution controls like fuel cells and pipeline injection are also allowed, but these are more expensive than catalytic converters and rarely used in the dairy industry.
Despite these problems, the Bay Area and Yolo-Solano districts in northern California are looking into the same rule changes, and, according to Allen Dusault of the San Francisco-based Sustainable Agriculture, other counties will follow suit.
“According to the Clean Air Act, districts have to adopt the highest standard implemented in the state,” he says. “If one air district implements a pollution control technology, other areas with similar pollution problems must adopt or surpass. Many districts look to San Joaquin and South Coast for guidance, so their decisions have a big impact and need to be well thought out.”
Whether the rules are adopted for Santa Cruz, Monterey and San Benito counties will depend largely on the number of new digester applicants. “If they can build a better mouse trap this way, we will be following them a few years down the road,” says Lance Ericksen, engineering division manager at the Monterey Bay Unified Air Pollution Control District.
Currently the Santa Cruz and Watsonville Wastewater Collection and Treatment facilities run the only two local methane digesters. The Santa Cruz system captures 100 percent of the methane produced at the plant. With a little help from solar panels, it generates 60 percent of the facility’s power.
“We have always met our emissions requirements,” says Dan Seidel, wastewater superintendent, “but we might not if the new restrictions make their way up north. They aren’t here yet, but they are making a big impact in Southern California.”
The plant just rebuilt its primary engine, which runs on a methane-biogas blend. The agency is permitted for six times higher emissions than would be allowed for a new digester.
Climate Concerns
This may be the first time in the nation that emissions concerns have undermined climate change efforts. Methane is over 20 times more potent a greenhouse gas than carbon dioxide, according to the EPA, and without digester tanks, manure goes into an open lagoon, releasing the pollutant into the atmosphere. “The volume of methane we collect is equivalent to taking 5,000 cars off the road,” says Drake of his renewable biogas systems.
But Warner says climate change is out of his and the air district’s jurisdiction. “There are a lot of different ways of looking at ‘green,’” he says. “We absolutely agree that greenhouse gas reductions are very important. But our board has made it clear that our job is to protect the health of [local] residents.”
While the World Health Organization says climate change is increasing malaria and vector- borne diseases, Warner is more concerned about the local impacts of the infamous particulate-forming pollutant called Nitrogen Oxide (NOX). Like cars, coal power plants and just about any gas-powered engine, methane generators release NOX. The rule changes are specifically designed to target these emissions.
“NOX is everything,” says Warner, “it impacts fine particulate matter, which goes into the lungs. It is also a precursor for ozone pollution, which causes respiratory problems like asthma and emphysema.”
Seated at his office desk, Warner scrolls through a database of permitted dairy farms. He says the EPA requires the San Joaquin Valley to reduce NOX emissions by eight tons a day. “If every dairy [installed a digester], they would create, according to our calculations, about five tons per day increase in nitrogen oxide emissions, virtually wiping out the eight tons per day reduction.”
Yet focusing exclusively on local emissions reductions is a bit shortsighted, says Greg Kester of the Sacramento-based California Association of Sanitation Agencies. “These rules went into effect before clean energy was a reality,” he says. “Instead of selecting for the cleanest form of energy and the best way to get rid of pollution, we are targeting a single pollutant as if it holds the key to these larger issues.”
In addition to reducing methane emissions, digesters remove particulate and ozone-forming pollutants from the air. Manure releases air pollutants such as ammonia, volatile organic compounds, and sulfur dioxide. Studies have shown that clean-burning digester facilities effectively remove these toxins.
Dairy digesters also emit less NOX than coal plants. Even though electricity plants in the San Joaquin Valley meet strict NOX emissions requirements, California still gets 20 percent of its power from coal—most is imported from Arizona where standards are more lax. “The San Joaquin Valley uses this brown energy too,” says Dusault, “and as far as some air pollution concerns go, there is a net benefit to using a digester, not to mention the tremendous green-house-gas benefits.”
As importing brown energy from other states doesn’t impact local NOX levels, Warner says this issue is also out of his jurisdiction. “We want to help environmentally sustainable technologies work. But the rules apply to everyone.”
The Gallo and Fiscalini farms say they will continue to comply. When the generators are down for repairs or out of compliance, the methane will be burned off with a flare—a technology that releases NOX into the air without creating energy.
