Anaerobic Digest

BioCycle May 2012, Vol. 53, No. 5, p. 14

Chaseburg, Wisconsin: Small Dairy Herd Feeds Power Co-Op

Small dairy sells renewable energy generated from anaerobic digestion.

Peters Farm dairy, near Chaseburg, Wisconsin, installed a 45kW digester.

Dairyland Power Cooperative is purchasing power from a modest-sized dairy that has set up one of the first small-scale, on-farm anaerobic digester projects in the region. Peters Farm dairy near Chaseburg, Wisconsin had the 45 kW digester installed at its 200-cow dairy. The Universal Sanitary Equipment Manufacturing Company (USEMCO) developed the technology specifically to serve small-herd enterprises. “Wisconsin is known for its many small, family owned dairy farms,” says USEMCO President Pat Rezin. “By developing a digester system that taps the renewable energy of these farms, we are greatly increasing the potential production of renewables and helping farmers minimize farm waste.” More than 13,000 of Wisconsin’s 14,000-plus dairy farms have a herd size of less than 200 animals. USEMCO was awarded a competitive $200,000 Wisconsin Special Agriculture Facility Grant as part of the state’s 2009-2011 budget to facilitate development and demonstration of a digester that would be cost-effective for smaller farms.

The Peters Farm digester, which cost a little more than $1 million, is the company’s pilot project. While USEMCO shouldered the initial bill for the venture, in the future it will provide the technology, construction and maintenance, and the farmer will own the project. “In some places, it may be more advantageous for farmers to use all the energy generated on their own farm,” says Rezin, a civil engineer by training. “Elsewhere, it might be more advantageous to sell it. Every power company has different policies on how they pay for renewables.” Peters Farm is capturing excess heat off the genset to preheat water for use in the milking parlor, both for sanitizing equipment and for radiant floor heating in the winter, and will utilize the digested solids for bedding material.

Dairyland Power, which signed a power purchase agreement with the farm, provides wholesale electricity to 25 member distribution cooperatives and 16 municipal utilities across Wisconsin, Minnesota, Iowa and Illinois (in this case, the digester power is serving Vernon Electric Cooperative). Peters Farm represents its eighth digester project. “Dairyland Power is a national leader in terms of quantity of on-farm digesters producing renewable energy for our cooperative system,” says the company’s Manager of Business Development Craig Harmes. “We are pleased to be part of a partnership which produces more renewable power locally while offering great promise for small family-owned farms.”

Covington, New York: Dairy Group Ramps Up Codigester

The Synergy Biogas, LLC anaerobic digester in Covington was commissioned in December 2011. By late March, it was receiving about 11,000 gallons/day (gal/d) of food waste, which it digests with dairy manure produced by about 1,800 milking cows from the adjacent Synergy Dairy, which is owned by Synergy, LLC, a partnership of large-scale dairy and field crop producers in western New York. CH4 Biogas, LLC formed Synergy Biogas to own and operate the digester, which leases land from the dairy. The site is permitted to receive 40,000 gal/d of food waste, which (at design capacity) will be codigested with 55,000 gal/d of manure and 5,000 gal/d of other dairy wastes. “We have about two days worth of storage capacity,” said Paul Toretta, CEO of CH4 Biogas during a recent tour. “The food waste receiving tank is sized at 100,000 gallons, as is the manure receiving tank.”

The plant uses the Bigadan A/S digester system, a continuously stirred tank reactor. Incoming feedstocks pass through a heat exchanger on their way to three 8,000 gallon pasteurization tanks, which hold the material at 158°F for one hour. The pasteurized biomass is then pumped to the digester vessel through the heat exchange system to bring the temperature down to 100°F (mesophilic range). The digester tank has a design loading rate of 100,000 gal/d, with a retention time of 22 days. Treated effluent is transferred to the biomass/gas storage tank where it is retained for up to four days prior to being pumped to screw press separators to produce solids for bedding. Biogas is treated by a biological filter (a 21,000-gal packed media column) to reduce hydrogen sulfide. Scrubbed biogas fuels a Jenbacher engine to generate 1.4 MW of electricity. Total cost of the system was $7.8 million.

Oakland, California: EBMUD Generates Power Surplus

In early April, the East Bay Municipal Utility District (EBMUD) in Oakland cut the ribbon on a $32 million anaerobic digester (AD) expansion that doubles the facility’s capacity to produce renewable energy from the waste it processes. EBMUD also holds the distinction of being the first sewage treatment facility in the country to codigest food scraps for energy. “We’ve turned waste into commodities,” EBMUD Director of Wastewater David Williams said during a ceremony marking the event. At the heart of the combined heat and power (CHP) project expansion is a new low-emission turbine producing an additional 4.6 MW of power. The installation supplements three existing generators and enables EBMUD to produce about 120 percent of the energy it consumes, making it the first wastewater treatment plant in North America to produce more renewable energy than it consumes.

Along with the expansion comes more aggressive collection of food waste (see “Utility District Ramps Up Food Waste To Energy Program,” November 2011). San Francisco and its waste hauler Recology, which together run a mandatory residential and commercial organics recycling program in the city, have also partnered on the EBMUD project and are providing feedstock and other support in order to test the waters for launching a similar organic waste to energy project. The San Francisco program currently processes about 220,000 tons of collected organics annually into compost.

San Francisco, California: Data Centers Could Boost Biogas

An article published April 22, 2012, by the online technology news provider GigaOM suggests that siting data centers that power the world’s never-sleeping websites near biogas projects and their feedstock sources makes sense for a host of reasons and has already become common practice. For example, Apple’s iCloud data center in Maiden, North Carolina, will be powered up to 25 percent by a 5 MW fuel cell farm that is expected to eventually run on 100 percent directed biogas — biogas that is cleaned, monitored and injected into a natural gas pipeline. Apple will initially use natural gas, according to the article, and has not disclosed where it plans to source the biogas. Microsoft is also planning a fuel-cell-powered data center called Data Plant, according to GigaOM, that will run directly off biogas and be sited at either a wastewater treatment plant or a landfill site. And, as reported in BioCycle in October 2011, Google has teamed up with Duke University and Duke Power to partially fund an anaerobic digester at a 9,000-head North Carolina swine farm (although that project is not currently connected to any data center). GigaOM also reports that eBay has Bloom Energy fuel cells powered by biogas at its headquarters in San Jose, California.

Says GigaOM blogger Katie Fehrenbacher: “Data center operators are looking at biogas as a way to reduce their carbon footprints, do green PR and control their source of energy. Data centers are rapidly being built throughout the U.S., and large data centers suck up a lot of power.”

Washington, DC: Ag Committee Restores Funding For Farm Bill Energy Title Programs

The Senate Agriculture Committee approved a new version of the 2012 Farm Bill on April 26 that includes an amendment introduced by Sens. Kent Conrad, D-ND, and Richard Lugar, R-IN, to restore funding for the Farm Bill’s Energy Title programs. The amendment provides $800 million in mandatory funding for core energy programs through fiscal year 2017. According to the Agriculture Energy Coalition, a group of organizations committed to a strong bipartisan Energy Title in the Farm Bill, among the included programs are the Rural Energy for America Program (REAP) that has been a significant source of funding for agricultural digesters, and the Biomass Crop Assistance Program, an initiative focused on establishing and maintaining significant quantities of energy crops. The full Senate needs to approve the bill and the House is working on its own version of the Farm Bill, which is expected to differ from the Senate’s. Without reauthorization in the 2012 Farm Bill, Energy Title programs will expire September 30, 2012, notes the Ag Energy Coalition.

Farm Bill Energy Title programs incentivize billions of dollars in private investment, point out supporters of the programs including the American Biogas Council (ABC). In 2011, various USDA programs helped develop more than 60 dairy-based digesters. For example, REAP provided nearly $21 million in assistance for biogas systems and leveraged more than $110 million in project development. “We commend Senators Conrad and Lugar and the numerous cosponsors for ensuring funding for these crucial farm energy programs,” says Patrick Serfass, ABC’s executive director. “While continued funding is far from guaranteed at this point in the legislative process, the Senate Agriculture Committee’s vote was an encouraging show of support for farm energy programs that foster new agricultural markets and support rural economic self-sufficiency. Ensuring mandatory funding for the Energy Title of the Farm Bill has been a top priority for ABC this year.”

Auburn, New York: Long-Awaited Community Digester Going On Line

USDA Rural Development hosted a press event this spring to celebrate the grand opening of the Cayuga County Soil and Water Conservation District Community Digester. The event also kicked off the Got Manure? Enhancing Environmental and Economic Sustainability Conference in nearby Syracuse, co-hosted by the US EPA’s AgSTAR Program, Cornell’s PRO-DAIRY program, New York State Energy Research & Development Authority (NYSERDA) and the New York office of USDA’s Natural Resources Conservation Service. Once it goes online this summer, the Cayuga County Soil and Water Regional Digester will accept up to 35,000 gallons daily of manure trucked from local dairy farms and up to 8,500 gallons daily of food waste and FOG (fats, oils and grease) from local food processors/retailers and restaurants. Blue Electron developed and will manage the project, which used GBU Germany to design the system. The hydraulic mix digester system has no internal moving mixers, and instead relies on pressure differentials between the inner and outer tanks gas head space to mix and move the digesting materials, according to PRO-DAIRY. The system is designed to process solids concentrations up to 18 percent.

Treated biogas will be piped to a 633 kW Jenbacher genset, which will provide electricity and heat to onsite and other county buildings. Excess power will be sold to New York State Electric & Gas Corp. (NYSEG) under a power purchase agreement. The project was partially funded with a $6.2 million American Resource and Recovery Act grant. An additional $3.5 million in federal and state grants and aid included $500,000 from USDA Rural Development, $1 million from NYSERDA, $750,000 from USEPA, $500,000 from NRCS and $60,000 from New York State Department of Agriculture & Markets. Initially two farms, located 12 and 7 miles away from the facility, will be participating in the project.

Palo Alto, California: Biodegradable Plastic From Biogas

A new start-up company is producing biodegradable, biobased plastic from waste methane gas with technology developed at and licensed from Stanford University. Mango Materials CEO Molly Morse, who helped invent the process while earning her PhD at Stanford, shared the company’s story on April 17 at the 26th Annual BioCycle West Coast Conference in Portland, Oregon, along with the company’s Director of Biological Research Anne Schauer-Gimenez. Morse explained that the closed loop process converts methane generated by anaerobic digestion to a biopolymer (PHA) through a microbial process. The PHA is “the polypropylene of bioplastics,” says Morse, describing it as “bacterial fat” where excess carbon is present and/or when key nutrients are limited (thus prompting the microbes to store energy). The biopolymer is sold as pellets for production of plastic goods such as cell phones, computers, toys and food packaging and can be reprocessed to produce more biogas and continue the cycle.

Mango Materials is only producing research quantities at this time, at a cost of about $2.75 a pound. The company is interested in partnering with biogas producers. “It is another option for them to have a different revenue stream,” said Morse. The initial Mango Materials research was partially funded through a National Science Foundation grant.

Related Posts Plugin for WordPress, Blogger...

Tags: , , , , , ,

Comments are closed.