Don’t let waste go to waste. That’s Gary Radloff’s thinking. The interim director of the Wisconsin Bioenergy Initiative (WBI) housed at the University of Wisconsin-Madison says “we have the opportunity to take waste and make something of it!”
Radloff, who recently keynoted a roundtable session called Biogas Opportunities in Wisconsin and The New North at Short Elliott Hendrickson in Appleton, is a firm believer that “this region of the country is well positioned to take advantage of the bio-economy – lots of historical experience with wood pulp and agriculture.”
Biogas is produced by the anaerobic (absence of oxygen) decomposition of organic matter. Waste such as cow manure, crop residue or byproducts from milk and cheese plants is fed into a closed vessel called a biodigester. There, microbes in the presence of heat and absence of oxygen break down the organic matter to create biogas, which is made up of 50 to 75 percent methane.
The methane can be then combusted for electricity and heat or upgraded for use in pipelines or transportation fuel. Depending on the digester technology chosen, there can be two other valuable byproducts of the decomposition process: nutrient-rich solids that can be used for fertilizer, animal bedding, particle board or fill dirt; and a non-odorous liquid rich in nitrogen, potassium and phosphorus that can be applied to farm fields as fertilizer.
The interest in biogas has grown significantly in the past 15 years, Radloff says. Germany is the world leader in this technology, with more than 6,000 plants.
In contrast, as of December 2010, there were only 152 farm scale biogas facilities in the United States. Wisconsin leads all states with 26 on-farm plants.
The Wisconsin Bioenergy Initiative’s 2011 strategic plan points out that about 82 percent of Wisconsin’s energy comes from out-of-state sources. About $18 billion leaves the state each year to purchase energy for businesses, power to heat homes and fuel vehicles. The same research shows that, if the 23 million tons of manure produced each year were converted to natural gas, Wisconsin would offset 4.4 percent of its energy need – a $185 million underutilized opportunity.
Andrew Dane, senior community development and sustainability specialist at Short Elliot Hendrickson and leader of several anaerobic digester feasibility studies, also sees another potential advantage to biogas conversion: removing waste as a pollutant.
“We’re already spending a lot on the environment to improve water quality after the fact,” he says. “Is there a way to incentivize approaches that help prevent these issues in the first place?”
Wisconsin is a leader in biogas conversion technology manufacturing as well. GHD Inc., the U.S. market leader in biodigesters, was founded in Chilton in 1989 by Steve Dvorak. The company has 76 digesters operating in 15 states, with another 24 digesters currently under construction.
“Our approach is called mixed plug flow,” says GHD marketing manager Melissa VanOrnum. “The new waste going in pushes the old forward so we can regulate that every gallon is in the biodigester for 22 days. That gives us maximum energy out of the manure.”
GHD’s biodigesters are in-ground rectangular installations, and are covered by concrete panels.
Another technology is the NB System developed by Northern Biogas of Green Bay. Its above-ground, round-tank system is based on European design, but adjusted for size and the harsher climate of the upper Midwest.
“We use a double-membrane roof, where the outer one is always inflated, and the inner one rises and falls with gas production,” says Grant Grinstead, one of the owners.
Northern Biogas has 10 installations so far in the Midwest and Idaho, and is also looking at opportunities in South America and China.
A key is that all of these take materials that would ordinarily be disposed of as waste and turn them into components that have the potential for economic value. Manure management alone has been described as a “$48.5 million headache” in a report by the CHANGE sustainability graduate program at UW-Madison because of groundwater contamination issues, odors and greenhouse gas emissions.
In addition, according to the Wisconsin Department of Commerce, the state has more than 1,000 food-processing facilities, including breweries, cheese producers and processors of meat, fruit, vegetables and grains. These also produce waste that must be dealt with.
“The ‘ticket to entry’ for this movement is having woody biomass and agricultural-related feedstock – especially dairy – and we have that in spades,” says New North, Inc. executive director Jerry Murphy. “We’re also very diversified and that helps unique, innovative things work here.”
Similar to its role with the Wisconsin Wind Works, New North is helping to establish the Biofuels Advisory Group, a core group of leaders who will help define the issues, opportunities and potential economic value for the region.