Researchers at Cornell are working on a three-phase system to convert cow manure into renewable natural gas that can be used to meet peak wintertime energy demand. Photo by Shutterbug75/Pixabay
Dec. 22 (UPI) -- Engineers at Cornell University in upstate New York are working to develop a system to extract energy from cow manure to meet increased heating demands.
In a paper published Tuesday in the Journal of Renewable and Sustainable Energy, researchers detailed the scientific and economic challenges posed by the prospects of installing such a system.
Cornell is a part of a group of colleges and universities that have pledged to be carbon neutral, completely erasing their carbon footprint, by 2035.
Though no small feat for any large institution, the challenge is especially difficult for colleges and universities situated in places where long, cold winters are the norm.
A sizable portion of Cornell's energy budget is spent heating the university's buildings and laboratories during winter.
Cornell already is working on a geothermal project that will use hot water extracted from nearly 2 1/2 miles underground to provide a sufficient baseline level of warmth.
Unfortunately, as a source of heat during the peak energy demands in winter, the geothermal system doesn't make economic sense.
To meet wintertime energy demands, researchers are working on a system to turn the manure from Cornell's dairy farms, home to about 600 cows, into natural gas.
The system features three stages, the first of which involves the biological breakdown of manure using microbes. The initial stage yields a biogas -- a mixture of methane and carbon dioxide.
During the second stage, the digested manure is converted into biocrude oil plus and a material called hydrochar, which can be used as a soil amendment on the school.
For the final stage, carbon dioxide produced during the first stage is combined with hydrogen gas extracted from lake water using a process called electrolysis, which involves the use of electricity to trigger chemical reactions.
The end product is renewable natural gas, RNG, that can be injected into New York's natural gas grid.
"The proposed system will produce about 909 million liters of RNG per year," study author Nazih Kassem, a biomedical engineer and visiting scientist at Cornell, said in a news release.
"This can provide 97 percent of the total annual peak heating demand. The remainder can be met by purchasing natural gas, increasing Cornell's dairy herd size, or using campus eateries' food wastes for co-digestion.
"Adding 19 more dairy cows would result in enough RNG production to meet the average annual peak heating demand."
The new research suggests that in order for the biomass heating system to make economic sense, Cornell will need help from policy makers in Albany.
"If New York state were to adopt policies to create a carbon market and enable competitive RNG pricing, then the proposed biomass peak heating system would show profitability," Kassem said.