In the Sunday 21 July issue of the Times Argus, Sandra Levine, a senior attorney at the Conservation Law Foundation in Montpelier wrote an article praising Green Mountain Power’s Cow Power program. She touted the program’s successes:
- 12 dairy farms producing ….
- Power for 3000 homes;
- While decreasing atmospheric carbon dioxide by 40,000 metric tons.
Ms. Levine believes that anaerobic digestion has a great future in Vermont because it supports agriculture and mitigates greenhouse gas pollution while producing renewable energy around the clock.
However, she notes that expansion of Cow Power faces a number of challenges. The technology is expensive – too expensive for small farms with limited herd size and manure production. Ms. Levine sees the connection between anaerobic digestion and Act 148. Farms could provide a destination for the organics we will soon be prohibited from landfilling. If farm anaerobic digesters are allowed to accept more than 49% non-farm organics and to accept the post-consumer residuals generated in our schools, cafeterias, restaurants and homes, farmers could harvest the energy and recycle the nutrients for crops.
We agree! And we believe that our AD project will show how small farms and their communities can make the best use of technology’s co-products: heat; nutrients and carbon dioxide. Because our AD is located next to the college’s central heating plant we can capture ‘waste’ heat and reduce our enormous use of fuel oil. Our Landscape Development and Sustainable Horticulture program would love to pipe exhaust carbon dioxide into a greenhouse in order to increase the rate of plant growth!
Ms. Levine worries that digestion of organic residuals will produce lots of nutrients. She worries that these nutrients could end up in our streams, rivers and lakes producing problems like those seen in Lake Champlain today. We believe that community or regional nutrient management could provide a solution. We are working with a group of eight Randolph farms that may benefit from the project by using digester nutrients in place of commercial fertilizer. The amount of land that can be served by the project will depend on the nature and chemical makeup of the food residuals that power the project. But we’re starting by collecting field, soil and crop data and creating nutrient management plans with our farm partners. Along the way we’ll be monitoring soil and water quality to demonstrate both the environmental and economic benefits of using AD to recycle, if not upcycle, ‘waste’ nutrients.
– Joan Richmond-Hall, Ph.D.