Farm Methane
Methane is a combustible gas produced by the anaerobic, or oxygen-free, digestion of vegetable and/or animal wastes. A number of projects around the country are using methane gas to generate power - and within the agricultural sector, there is growing interest in using farm wastes to produce methane. Anaerobic methane digesters can offer three key benefits to farms: power production along with odor reduction and improved nutrient management.
In Vermont, BERC has been a partner with two state agencies in a five-year, federally funded project to identify and resolve key issues in the way of widespread use by farms of methane recovery technologies. That initiative has led to the installation of three on-farm projects. Feasibility studies also found that in Vermont, cow manure is by far the largest source of organic material for methane recovery, and that these projects tend to be cost-effective on larger farms, with 300 or more cows.
- Odor reduction. Biomass systems can significantly reduce odor, which often plagues larger farms in areas of suburbanization.
- Nutrient management. Water runoff from manure is a very large contributor to nonpoint water pollution in the U.S.
- Power production. Using an existing product to generate electricity can improve a farm's balance sheet. On farms with significant heating needs, a combined heat and power (CHP) system may make sense.
- Doing due diligence on individual projects. No single system fits all. Methane recovery must be part of a farm's overall nutrient management program, and an array of technologies must be assembled in the optimum manner.
- Providing and clarifying solid, objective information, and helping farmers evaluate options.
- Helping farmers choose design and construction contractors.
Interest in methane recovery is especially strong in states and regions with severe nonpoint pollution problems, with large numbers of sizable farms, and/or with big feedlots. Early projects were not always successful, and a number of issues are being worked out. But as technologies improve and new systems come on line, efficiency and cost-benefits will continue to increase.