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WMUK Local

By: Brian Peterson
Hamilton, MI
December 11, 2011
WMUK

 

Scenic View Dairy bio-digester

Scenic View Dairy electric generator
Ever wonder where the electricity that powers your lights, appliances, and electrical devices comes from? You might be surprised that some of it may come from a dairy farm, as WMUK’s Brian Petersen explains:

Power generation may not be the first thing you associate with dairy farms. But the cows at Scenic View Dairy near Fennville produce more than just milk.

[Andy Austin] “The Scenic View Dairy Fennville facility implemented the anaerobic digester system in the summer of 2006, began producing electricity in the fall of 2006. It is on a 1900 cow head milking dairy with three complete mix anaerobic digesters.”

That’s Andy Austin, Scenic View Dairy’s Digester Manager. Anaerobic digesters use microorganisms to break down cow manure. The 22-day process ultimately produces bio-gas. Burning that bio-gas to power a generator converts it into electricity. Scenic View Dairy sells the energy to Consumers Energy which distributes it throughout its system. The utility’s Principal Financial Analyst, Mark Devereaux, says energy from such non-traditional sources represents only a small proportion of the energy on the grid:

[Mark Devereaux] “Consumers Energy has been announcing to its customers and in its public announcements that about five percent of the energy that is purchased and generated by the utility comes from renewable energy sources.”

That includes wind and solar as well as these biomass facilities. Devereaux says state law requires Consumers Energy to produce and distribute electricity generated using renewable sources. But he says another factor also contributes to the company seeking new sources of renewable energy.

[Mark Devereaux] “There is always the incentive from customer demand because there is a sizeable portion of our customer base that wants renewable energy, they want to see it developed, they want to purchase the output in some way from it.”

For Scenic View Dairy, using anaerobic digesters serves several purposes. It eases manure management, produces electricity it can use on-site, and provides an important income stream. Part of that revenue comes from selling electricity to Consumers Energy. But Peter Freed, a director at TerraPass, a carbon offset and renewable energy company in San Francisco, says it works with Scenic View Dairy to capture other revenue.

[Peter Freed] “We work with a bunch of different dairy farms that have anaerobic digesters and also with landfill projects across the country that are capturing and destroying methane gas to help them create carbon offsets and then to bring some financial benefits to the projects for the environmental good that those projects do.”

What is a carbon offset? Freed explains it this way:

[Peter Freed] “What the carbon offset is, is we are looking at the destruction of methane gas that would otherwise have gone into the atmosphere and contributed to climate change, to global warming.”

Scenic View Dairy has meters in its digester facility that track how much methane has been converted into electricity. TerraPass buys those carbon credits from the dairy and sells them as offsets. Some go to companies but TerraPass also sells them to individuals who want to offset their own greenhouse gas emissions. For example, Freed says people can track emissions generated by their vehicles:

[Peter Freed] “So, on our website, we have calculators and you can enter in the make and the model of their car, how many miles you put on it per year, and then using standardized factors from the EPA we can figure out how many emissions your car would have put out in the course of a year and then you would buy an equivalent amount to mitigate the impact of those emissions.”

Freed says the smallest amount of carbon offsets you can buy is equivalent to a thousand pounds of carbon, which currently sells for $5.95. Increasing consumer demand for these offsets provides Scenic View Dairy another benefit from building the anaerobic digesters, which cost $3.2 million.

The digesters generate more than just electricity according to the dairy’s Andy Austin.

[Andy Austin] “The uniqueness of this facility was it was the first one in the country that could produce both the electricity and the gas operating system which produce the natural gas or bio-methane and sold them both back to their respective grids.”

The anaerobic bio-digester at Scenic View Diary does provide economic returns but Austin says that wasn’t the primary factor that persuaded the dairy’s owners to install it.

[Andy Austin] “The major reason was to be ahead of the curve, they want to be innovative.”

There are thousands of dairies around the country but very few have bio-digesters. Peter Freed at TerraPass suggests that another motivation persuades some owners to install them.

[Peter Freed] “There are only 150 digesters in the United States so what they are doing is really on the cutting edge of technology, it is on the cutting edge of environmental responsibility and its not like it’s a big profit center for them it was really a personal drive to do something good for the environment that caused them to put that in.”

Consumers Energy currently has four contracts with dairy digester facilities. But the renewable portfolio standard the state passed requires increased electricity production from renewable sources. Officials at Consumers Energy and the Michigan Public Service Commission say they expect more of these facilities to be built in the future, in part due to the new standard. That means it will become more likely that electricity in your home may have come from that most unlikely of places: a dairy farm.

 

BioCycle November 2011, Vol. 52, No. 11, p. 39

Oakland, California’s wastewater treatment plant’s seven-year-old postconsumer food waste-to-energy program — the first in the United States — is ready to grow.

Paul Hagey

THE East Bay Municipal Utility District (EBMUD) in Oakland, California has been a pioneer in tapping the energy in food waste to boost biogas production in its wastewater treatment plant (WWTP) digesters. Now, the utility’s food-waste-to-energy program is taking some significant next steps. In the next 24 months, the District will begin a 120 tons/day (tpd) postconsumer food waste contract with an area hauler who is building a preprocessing facility at the WWTP, designate a food waste only anaerobic digester, start up a new 4.5 MW CHP unit that will generate all of the energy the plant needs to operate, and sell excess biogas-generated electricity to the local power grid.

“Nobody’s ever done 120 tpd before,” says EBMUD wastewater plant director David Williams. The treatment plant, which serves 650,000 residents in the East Bay, currently uses seven anaerobic digesters to process about 40 tons (10,000 gallons) of commercial postconsumer food waste each weekday. EBMUD charges a tipping fee to receive the food waste. The plant also receives 240,000 gallons/day of food processing waste for digesting. These materials are mixed with the municipal sludge (700,000 gallons/day are generated) and added to the digesters.

Located at the base of the Bay Bridge in Oakland, the WWTP now generates 90 percent of the 5 MW it needs to operate. It has three 2.1 MW internal combustion engines fueled by its biomethane. Downtime for the 25-plus-year-old engines, both scheduled and unscheduled, currently limits the plant from covering all of its energy needs. Additional electricity is purchased from the grid. Heat recovered from the engines is used to warm the digesters to their thermophilic operating temperature, and to provide heat elsewhere in the plant. When the new turbine goes online in early 2012, the plant will begin to produce more energy than it needs.

EBMUD began experimenting with the addition of food waste to its digesters in 2004 through a collaboration with Recology, a Bay Area resource recovery company. A 2007 bench-scale study by EBMUD, funded in part by an EPA research grant, (see “Green Energy From Food Wastes At Wastewater Treatment Plant,” January 2008) found that food waste generates about three times the biomethane as municipal sludge during anaerobic digestion. The study helped to accurately quantify methane gas production rates, mean cell residence time requirements, and volatile solids reduction values that are specific to food waste digestion. “It’s a really awesome substrate to be digesting,” says EPA scientist Laura Moreno, who worked with EBMUD to develop its program. The study also showed that food waste can be digested at higher concentrations, breaks down more completely, and has a shorter digestion time than sludge.

SOURCING FOOD
The Bay Area generates about 2,100 tpd of commercial food waste. Five percent or more of the 2,100 tons, from restaurants and grocery stores in San Francisco, Oakland and some rural neighboring counties, will end up at EBMUD when it completes the next phase of its program.

Recology collects over 500 tons/day of organic material including postconsumer residential and commercial food waste in San Francisco and processes it at its composting sites in the region (including Jepson Prairie Organics and Grover Environmental Products). The contract between Recology and EBMUD is to provide 120 tpd of food waste and process it at a new facility to be constructed at the plant. Preprocessing involves removing coarse contaminants and reducing the size of the material. The facility, which Recology will own and operate, will be a stone’s throw from EBMUD’s anaerobic digesters and food waste receiving area. It will have enough capacity to handle significantly more material than the current contract’s 120 tpd.

Allied Waste Services, a hauler that delivers about 40 tons/week of preprocessed food waste to EBMUD, is building a preprocessing facility in nearby Martinez, which will lower hauling costs. This 40 tons/week is from a commercial food waste collection program initiated by the Central Contra Costa Solid Waste Authority (CCCSWA). The preprocessing facility is on schedule to be completed in early 2012, says Allied Services general manager Tim Argenti, and will be capable of handling 60 tpd. Allied will continue to service CCCSWA’s diversion program. EBMUD is exploring new contracts with other haulers to supply food waste for the plant as well. “Converting food waste to energy is a can’t lose situation for us,” says Paul Morsen, executive director of CCCSWA, which has sent all of its commercial separated food waste to EBMUD since 2008 (see “Pioneering Partnership Optimizes Power Production).

HISTORY AND DESIGN
The EBMUD wastewater treatment plant, built about 60 years ago, incorporated 12 digesters to handle the high-flow, high-strength organic waste from the canning industry that thrived in the East Bay by the 1970s. Peaches, pears, spinach, tomatoes, fish and other foods fed an estimated 72 canneries that dotted Oakland, Berkeley and Emeryville. The last cannery, owned by Del Monte, closed in 1992. Loss of that industry left a lot of excess capacity at the plant.

About 10 years ago EBMUD started looking for ways to utilize the unused digesters. “We thought, why not explore other waste streams,” says Williams. EBMUD started with easily-processed waste like liquid from portable toilets and oils and greases from restaurants. In 2004, it added postconsumer food waste as a feedstock on an experimental basis.

One of the major hurdles to using postconsumer food waste as a feedstock for wet anaerobic digestion is that it must be processed prior to blending with other substrates, including preprocessing to remove contaminants. Unlike food processing waste, postconsumer food scraps can come laced with contaminants like cutlery, plastic, cloth and seafood shells. After experiencing seafood shell-clogged outlet pipes and cutlery-damaged pumps, EBMUD developed its patented food waste processing system for anaerobic digestion.

On the plant’s north end stand 12 white two million gallon anaerobic digesters. Five of them are not being utilized now. About 22 yards away lies the food waste staging area. The District’s food waste processing system works in several stages. The preprocessed postconsumer food waste arrives at the site primarily in tarp-covered transfer trucks that unload into one of three underground slurry tanks through ground-level doors. A heavy-duty rotocutter then grinds and settles out the large, indigestible items like stones, metal and seafood shells left in the mix. Incoming food waste needs to be in the 2- to 3-inch size range.

Next the mixture arrives at the heart of the processing setup, a four-blade paddle finisher that extrudes a ready-to-digest fine pulp through an interchangeable screen. The blades rotate along the interior of the cylindrically-shaped screen, extruding digestible pulp through its holes. Material not pushed through the screen is discharged into a nearby open-top hauler as a finely-shredded, landfill-bound reject. A progressive cavity pump then sends the pulp to the nearby digesters. The system processes about 250 gallons of slurry per minute and retains about 95 percent of the slurry’s biogas-generating potential.

Currently, processed food waste mixes with municipal sludge and is sent to all the active digesters. Food waste codigested with biosolids is a Class B product that is used as alternative landfill cover or applied to agricultural soils. Soon, the processed food waste will remain separate and feed a food waste-only digester. Digested food waste solids, after composting, can be used as certified organic soil amendment.

The dedicated digester will be managed similarly to the municipal sludge codigesters. It will operate at thermophilic temperatures with a minimum of 122 ºF and be initially started up with municipal sludge, then transitioned to food waste only. Higher degradation rates and thus shorter retention time in the digester are anticipated. According to EBMUD’s 2007 bench-scale study, food waste requires about a third less retention time than municipal sludge, can be processed at five times the concentration and produces three times as much methane.

Nov. 1 — A bill in Congress would allow for a 30% energy tax credit for qualified waste-to-energy projects, but opponents say the tax break is unnecessary and should go to “cleaner” renewable projects.

H.R. 66, filed in January, would give the tax credit for systems that use municipal solid waste or sewage sludge as feedstock for producing solid, liquid or gas fuel. The bill excludes landfills from approved projects.

A similar bill was introduced in 2010, but it did not leave committee. The bill is sponsored by six Democrats and is in the House Committee on Ways and Means.

“With the right incentives, we can tackle our unsustainable waste management and our unsustainable energy sources at the same time,” said Rep. Lloyd Doggett, D-Texas, in an emailed response to questions. “This credit ensures that we find the most environmentally sound solutions.”

Doggett is the main author of the bill.

Ananda Lee Tan, spokesperson for the Global Alliance for Incinerator Alternatives, said subsidies to support waste-to-energy facilities are a drain on the economy.

“We´d like to see public support and incentives go toward real alternative energy options like wind and solar,” he said.

The bill does not pinpoint specific types of waste-to-energy technology, giving applicants a broad possibility of facilities.

The U.S. EPA would be tasked with evaluating applications for the credit based on environmental and energy criteria. Only projects that receive the highest scores, based on cleanliness and high energy content, would get a tax credit, Doggett´s office said.

To be considered for the credit, applicants must prove that their lifecycle greenhouse gas emissions will result in a net climate benefit, Doggett´s office said. In addition, the tax credit would be capped.

“While this incentive faces an uncertain future in committee … we are continuing to build support for it among my colleagues and to make it a part of the conversation about waste management and alternative energy,” Doggett said.

Patrick Serfass, executive director of the American Biogas Council, said the group is pushing for passage, as it is open to allowing various waste-to-energy facilities besides incinerators.

“We think that favors anaerobic digestion because it´s a viable, competitive technology that creates energy,” he said.

Tan agreed that anaerobic digestion is the most promising.

“You want the highest end use of the material,” he said. “So [with anaerobic digestion], you´re making a fertilizer that you can put back into the soil instead of just burning the waste.”

There are other types of technologies that the bill would include, though. The United States lags far behind Europe in biogas technology, Serfass said, with about 10,000 operating biogas projects in Europe and only about 2,000 in the U.S. Serfass said this country could support about 11,000 biogas projects.

“The industry is very much just beginning in the United States,” he said. “But only with technology that is known. We´re trying to grow quickly and that means creating new business, new jobs and doing all that by converting waste to energy.”

Incentives are needed to level the playing field with other energy policy, Serfass said.

“The place that we´re behind right now is developing policies that keep us from wasting our waste and would instead incentivize folks to use it to make domestic, renewable base load energy,” he said.

Tan said his group opposes additional, more traditional WTE facilities because burning waste can be highly toxic.

“Burning plastics, paper bags, glass and metal and all that consists in municipal solid waste produces some really complex toxic compounds into the air that we breathe,” he said. “There´s also a huge problem with the disposal of the ash that is the end result.”

Recycling and composting are more effective, he said, and offer job growth.

“If we are going after the highest end use of these materials, we can´t be sending it to burn facilities and incentivizing that process any further,” Tan said.

Contact Waste & Recycling News reporter Jeremy Carroll at jcarroll@crain.com or 313-446-6780.

POMPANO BEACH, Fla. (CBS Tampa) — Believe in the power of poop. It’s an initiative being pushed by one South Florida energy company, which is now on the edge of being approved in Fort Lauderdale to help generate home electricity.

Power Green Energy, a Pompano Beach start-up hoping to turn sludge from waste-water treatment plants into renewable electricity for the state, is awaiting word today from the Fort Lauderdale City Commission to approve a rezoning request that would implement the system by the middle of next year.  The South Florida Sun-Sentinel reports that the company has received the City Commission’s tentative approval to initiate operations that would feed into Florida Power & Light Co.’s power-lines by mid-2012.

“To be able offset energy use for waste-water facilities with renewable energy or renewable gas from the very waste going into the facility in the first place is the optimum solution,” Patrick Serfass, executive director for the American Biogas Council in Washington, told CBS Tampa.

The proposed initiative is another step toward creating additional energy sources for the state, its tentative goal projected at 4 megawatts of electricity, or about 1,000-plus homes powered by the waste-to-energy plan. Currently, similar examples are also taking place in North Carolina and Wisconsin.

“This is taking a negative and turning it into a positive for our environment,” PGE Co-Owner Amie Silverman said to the Sun-Sentinel.

One of the important ideas behind PGE’s waste-to-energy plan stems from the idea of it all, anaerobic digestion. Through this, class-B biosolids from a wastewater facility, containing pathogens and bacteria, are processed through a digester, a vessel used for breaking down biodegradable material. Once the biosolids have gone through the process, they are upgraded to class-A biosolids, free of pathogens, bacteria, and viruses.

Though the digestate system has been in place for some time now, the PGE program signals an enhanced need for greater usage, sharpening the state’s focus on how to grow alternative energy.

“Digesters need regularity,” Serfass said. “They need businesses generating organic waste to basically enter into a contract to allow someone to come by and regularly pick up waste.”

Calls made to the Fort Lauderdale City Commission were not immediately returned.

The American Biogas Council is asking its members to urge their representatives in the U.S. Senate to support a bill allowing states to make their own decisions about incentivizing small renewable energy generation.

PURPA Plus, which was introduced to the Senate Energy & Natural Resources Committee in August, would modify the Public Utility Regulatory Policy Act of 1978. PURPA is still in effect today, and requires utilities to pay an “avoided cost” rate for certain types of small power production, cogeneration facilities and other types of qualifying facilities. “The problem with that is the avoided cost is usually the cost of the cheapest type of electricity the utility is generating,” explained Patrick Serfass, executive director of the ABC. “It might be generating power from wind, hydro, natural gas, nuclear and coal, but in almost every case coal is the cheapest and that’s what they are required to pay a biogas producer who is making electricity, for example.”

If that biogas producer has to turn on the facility’s lights or use power for something else, he’s probably paying a retail rate, Serfass said. “If he is selling any power back, he is getting a small fraction of that rate, so he’s not even getting paid the same rate he’s being charged.”

PURPA Plus would remove the avoided cost component from the bill, allowing individual states to set their own rates. “States get to choose if they want to encourage small distributed generation from renewable energy, that’s why it’s important,” Serfass said. “It allows them to create an incentive for renewable energy at no cost to the taxpayers. It’s a clear winner and something Congress and the public should get behind.”

He added that the ABC would like to see the bill’s cap of 2 megawatts (MW) lifted to 5 MW, as the many of biogas projects in the works in the U.S. are between 2 and 5 MW.

For more information, email mjwalsh@mlstrategies.com.