ITHACA, N.Y. — It’s a simple fact of life, energy bills are going to be higher in the winter as people all over the world heat their homes to stay warm. For researchers at Cornell University in chilly Ithaca, New York, this means keeping the heat on six months a year! Now, a team at the school says they have just what they need to make their own renewable energy and reduce their carbon footprint too. Their study finds the answer to their problem is cow manure, and that’s no bull.
Study authors are developing a system which extracts energy from a cow’s droppings, which they say can meet the peak demand for heat during the frigid winter months. So how many cows does it take to heat a 2,300-acre campus? The study finds manure from 619 cows could power this process and heat Cornell’s 260-plus buildings during peak usage periods in those frigid months.
The university’s dairy farms are already home to 600 cows. Officials there are also working to reduce the school’s carbon footprint by 100 percent by the year 2035. Another project trying to meet the heating demand — by providing heat from water extracted from deep underground — is also looking to ease the environmental impact of warming the campus. While this drilling process could meet the base load energy needs at Cornell at an economically attractive price, researchers say even geothermal energy runs into cost problems during peak demand.
The 3 steps to making heat from cow manure
Researchers working on the cattle project say a three-stage process can convert dung into methane and other renewable products. First, the cow manure is biologically digested with microbes to create biogas — a mix of carbon dioxide and methane.
Next, the digested dung is transformed into a biocrude oil and a substance called hydrochar, which is a good soil additive. Finally, carbon dioxide created by the first step is combined with hydrogen gas to biologically produce renewable natural gas (RNG).
Study authors say this final product is providing another resource in New York State’s efforts to decarbonize energy production. This works in a similar way to how wind turbines and solar panels return electricity to the power grid.
“The proposed system will produce about 909 million liters of RNG per year,” says author Nazih Kassem in a media release. “This can provide 97% 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.”
“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 adds.
The study appears in the Journal of Renewable and Sustainable Energy.