Three food facilities are turning away from fossil fuels for major cost savings, reducing their carbon footprint for environmental enhancement and grabbing sustainability awards for their success in implementing renewable energy solutions that rely on solar power, a unique burning system or anaerobic digesters.

Going solar

Fulper Family Farmstead is one of only 65 farms remaining in New Jersey, and it is the first dairy in the state to turn to solar energy as a way to improve its energy efficiency and increase its revenue while reducing its carbon footprint and cutting its utility costs.

“New Jersey ranks among the top in the country for implementation of solar-powered energy systems, behind states like California and Florida. As a business facing increasing operating costs, it is important for us to obtain electricity from renewable energy sources,” says Breanna Fulper, a member of the family-owned and operated 1,200-acre farm.

Fulper Farm has a history of taking a leading role in farm innovation. For example, it was one of the first to install a milking parlor that enabled multiple cows to be milked simultaneously—16 at a time in the 1950s—while increasing cow comfort by being gentler on the cows’ udders. The operation, established in 1909, currently milks 120 Holstein cows that produce 8,000 lbs. of milk daily.

The farm installed a free-standing, ground-mounted solar array designed and built by RCL Industries. The solar energy system produces 500 kWh of energy daily. “We have an older facility here. So, a traditional array is too heavy to be supported on the roof of the facility, which is why we put it on the ground,” says Fulper. The solar array sits on three-quarters of an acre of land. At the change of the summer and winter seasons, the farm repositions the angle of the photovoltaic panels to catch the most sun. 

The farm sells the energy to a local utility and then purchases back the electricity it needs to power operations. The farmstead’s electrical consumption is just a fraction of the energy it sells. The balance of the energy can power approximately 100 houses. Use of the sun-powered system generates solar renewable energy credits for Fulper Family Farmstead, which it sells for about $30,000 each year. Fulper says it might seem awkward to deliver the energy from the solar cell to the utility rather than apply it directly to farm operations, but it avoids having to install hydrogen tanks on the land to store the energy. “Hydrogen is explosive, and we don’t want to get in the business of storing explosive energy,” she explains.

The switch to renewable energy also lowered the farm’s utility bills. “Our electric bills amounted to $30,000 to $40,000 per year. With the installation of the solar-powered system and other sustainability efforts throughout the farm, the electric bill is about $6,000 per year,” says Fulper.

The family received more than $190,000 through a grant provided by the USDA Rural Development Rural Energy for America Program, as well as a $228,834 federal tax credit and $330,000 loan guarantee from the USDA. The current payback plan spans six years.

Efforts to establish renewable energy systems, implement soil conservation (crop rotation) methods and enact nutrient recycling plans helped the operation earn “honorable mention” in the Outstanding Achievement in Renewable Energy category of the 2013 U.S. Dairy Sustainability Awards, presented by the Innovation Center for U.S. Dairy. The awards are part of the U.S. Dairy Sustainability Commitment, an industry-wide effort to measure and improve the economic, environmental and social sustainability of the dairy industry. The dairy is also studying geothermal systems as a means to power the milk parlor with renewable energy.

Burning for bioenergy

General Mills produces oat flour for its cereal brands at two milling plants in Fridley, MN and northeast Minneapolis. In the process, it generates 90,000 tons of oat hulls as a byproduct. When the oat is milled into oat flour, roughly one-third of every oat kernel left over is a hull.

The company was looking to increase energy savings while reducing its carbon footprint at the mills and investigating the capability of repurposing oat hull as a renewable energy solution. “Oat hulls have 80 percent of BTU value or energy potential of bituminous coal with lower emissions,” says Trent Novak, project engineer and environmental/sustainability coordinator for General Mills in the supply chain operations division. According to the Department of Energy, oat hulls release the same carbon they absorbed from the atmosphere as plants, so burning is seen as carbon neutral.

General Mills knows oat hulls make great biofuel; it sells approximately 60,000 tons of the oat waste to Koda Energy, a local utility based in Shakopee, MN that burns the hulls, along with other exclusively natural agricultural byproducts, in a special biomass burner to produce steam that powers energy-making generators. Koda’s 100 percent biomass plant creates enough electricity to power 20,000 homes and enough thermal to heat 12,000 homes, according to General Mills.

In 2011, General Mills spent $3.3 million in capital to design, build and install the first biomass burner in the United States made solely to burn oat hulls. The biomass burner, manufactured by Hurst Boiler and Welding and installed in January 2011, produces steam as the fuel source. The burner replaces a natural gas burner, making the mill partially self-sustaining. Steam is used to power the mills that create the oat flour and byproduct hulls.

Approximately 9,000 tons, or 10 percent of the available oat hulls from the two mills, are burned in the company’s biomass burner. The steam energy provides 90 percent of the Fridley plant’s energy needs and saves a minimum of $390,000 a year in costs related to natural gas use, says Novak.

The move toward a renewable energy solution and away from nonrenewable energy reduced the plant’s carbon footprint by 21 percent. In addition, the burning process yields 1,150 tons/year of ash and raw oat waste as a byproduct that local farmers are using as a fertilizing agent and nutrient supplement. General Mills asked the state legislature to classify oat hulls as a renewable energy source so that, as a fuel, it would qualify as biomass.

The mill is a continuous processing unit that operates twenty-four seven. The biogas burner replaces 90 percent of the natural gas consumption at the Fridley plant, but it is not fully off the grid. “We are still consuming electricity and some natural gas,” says Novak. Gas boilers are put in operation during scheduled downtime for maintenance of the mill and burner and, in the winter, to provide heat. Electricity is used for operating motors and similar devices at the plant, states Novak.

The burner does take up more real estate than the natural gas burner, which sits inside a 40-ft. wide, 80-ft. long, two-story building. However due to the small size of the plant, the boiler had unique needs regarding automation, electronics and technology to meet new requirements for biomass boilers, according to Environmental Initiative, a Minnesota-based association that honors projects that have achieved extraordinary outcomes for Minnesota’s environment.

The oat hull biomass boiler project won the 2013 Environmental Initiative Award in the Business and Environment category for helping General Mills reduce its energy costs by using a byproduct from something they had already purchased. The award recognizes General Mills’ commitment to conserving natural resources and integrating sustainability into its strategies, operations and products.

Edible energy

Anaerobic digesters are becoming more familiar sites at dairy farms, but Green Valley Dairy, a 13-year-old, family-run dairy farm with 3,500 cows on 8,300 acres based in Krakow, WI was one of the first in the state to install such a system, deriving several benefits, according to John Jacobs III, family member and former dairy manager.

The dairy received complaints from neighboring residents about the lingering smell of manure, faced challenges to improving cow comfort issues that threatened milk production by stressing out the cows and was looking for a technology that could reduce its energy costs while forwarding its sustainability efforts for conservation and efficiency.

In 2005, Green Valley initiated key renovations, including the installation of two one-million gallon anaerobic tank systems from Biogas Nord of Germany. The farm also converted an 800hp methane-fueled engine to a 600 kW generator to use the methane given off by the digester as a renewable fuel source. Heat from the generator is routed to the shop floors and calf barns during the winter months.

In 2008, the farm added 1,000 more cows and installed a third anaerobic tank—this one from Northern Biogas—while converting a second diesel engine into one designed to use methane. The two 600 kW engines generate 1,200 kW, says Jacobs. Green Valley sells the energy to a local utility and buys back what it needs for day-to-day operations. The electricity sent to the utility not used by the dairy farm is enough to power 1,200 homes, where an average home uses 1 kW, says Jacobs. “We probably use one third of the energy we produce on the dairy. The utility takes the rest and uses it to offset its electric generation it sells to customers,” explains Jacobs.

“Microbes in the anaerobic digester eat the volatile fatty acids contained in the manure, excreting methane gas as a byproduct,” says Jacobs. The effluent coming from the barn is 8 to 8.5 percent manure solids and 90 to 92 percent water. Effluent is transported to the digester tanks, which heat it to approximately 100°F—a temperature ideal for the proliferation of a certain family of microbes the farm desires. Boat-like propellers stir the material for uniform digestion by the microbes. Methane is captured by a rubber-like balloon over the top of the kettle tank while the residual effluent, now containing 6 to 6.5 percent manure solids, is run through a screw press where fibers are extracted and used for stall bedding.

Prior to the installation of the anaerobic digester system, Green Valley used sand in the stalls. The switch of bedding material to the fiber made onsite at the farm eliminated the need to haul sand in and out, generating a cost savings of $245,000 annually, says John Jacobs IV, dairy manager.

The screw press divides the effluent into solid and liquid parts. Jacobs says the anaerobic digestion process also carries out a pathogen kill useful for the bioliquids that are used to fertilize cropland soil. “The nutrient level remains about the same after the process, while the digestion of the volatile fatty acids eliminates the odor,” says Jacobs. The anaerobic process makes the nutrients in the biomaterials more available to microbes in the soil. Green Valley shares its best practices with others as a way to improve public perception regarding sustainability and new approaches to a natural ecosystem at work in a modern plant.

The elimination of the manure smell, change of cow bedding to a renewable resource, generation of methane gas and reduction of natural gas consumption were part of a package of programs promoting the farm’s sustainability efforts relating to economic, environmental and social actions. The farm was recognized this year with an award for Outstanding Achievement in Renewable Energy by the Innovation Center for U.S. Dairy.

Big biogas

Large-scale anaerobic digester biogas systems designed to handle different substrates from expired food to fat and grease or slaughterhouse waste are finding an increasing number of applications in the United States, says AAT Biogas Managing director-Technik, Christian Kloser. “There are a lot of substrates in the US that shout to be treated in a biogas plant from an environmental standpoint. I am seeing that the investments are high, and payback times of four to seven years are targeted for the US market.”

AAT has built over 100 biogas plants in more than 25 countries. In January, AAT installed its second biogas plant in the US—near Charleston, SC. It will generate 1.6 MW electric energy from the digestion of wastewater treatment plant sludge as well as fat, according to Kloser. The first system the company installed in the US is at Stahlbush Island Farms (Food Engineering’s 2012 Sustainable Plant of the Year). v

For more information:

Christian Kloser; AAT Abwasser- und Abfalltechnik GmbH; 43 (0) 5574 65190 18, christian.kloser@aat-biogas.at

Alexander Rechter; Biogas Nord AG; 49 521 9633 0; info@biogas.de

Jeff Hurst; Hurst Boiler & Welding Co. Inc.; 877-994-8778; info@hurstboiler.com

Grant Grinstead; Northern Biogas; 920-948-3216; info@northernbiogas.com

 Bob Laroy; RCL Enterprises; 856-339-4014; rclsolar@comcast.net