Energy Efficiency Measures

COMBINED HEAT AND POWER

To learn more about CHP, visit the website of the Intermountain CHP Center. The Intermountain CHP Center promotes greater adoption of combined heating, cooling, and power technologies in the states of Arizona, Colorado, New Mexico, Utah, and Wyoming. The Center works in the areas of project support and facilitation, education and outreach, market assessment, policy review, and coalition building. Visit the Intermountain CHP Buyer’s Guide website to access information about vendors, contractors, and distributors who can turn your project idea into reality.

Combined heat and power (CHP), also known as cogeneration, refers to generating electricity at or near the place where it is used. The waste heat from the electricity generation can be used for space heating, water heating, air conditioning, water cooling, waste treatment, or for nearly any other thermal energy need. The end result is significantly more efficient than generating each of these separately. CHP is sometimes called “recycled energy” because the same energy is used twice—once for electrical energy and once for thermal energy.

Concentrated animal feeding operations including hog farms, dairy farms, cattle feedlots, and poultry producers have the unique opportunity to use animal waste as a “free fuel” for CHP, thus turning a cost into a benefit. Here are the steps:

Feed the waste into an anaerobic digester. There are several types of anaerobic digesters, including plug flow, complete mix, fixed film, and covered lagoon.
Send the methane produced by the anaerobic digester to a CHP system (first conditioning or treating the fuel if necessary).
Use the electricity for any on-farm needs and investigate selling any excess to the grid, as a renewable energy.
Use the waste heat from the CHP system to help maintain the process temperature of the digester, and/or use the heat for any other on-farm purpose (including space heating, water heating, or air conditioning).

Using an anaerobic digester to process waste has the following additional advantages:

Reduces neighbor complaints of odors.
Kills many of the harmful pathogens found in manure and kills weed seeds.
Co-products add another source of revenue. The fiber can be used or sold as an organic soil amendment, animal bedding, or potentially a replacement for peat moss used by greenhouses and plant nurseries. The nutrient water can be used as a fertilizer, and struvite, a precipitate, can also be used as a high-quality fertilizer.

About 40 anaerobic digester/CHP systems are operating in the US. Many more are operating in Europe – Germany alone has about 1,900 systems in place. Many of the digesters in the US in the 1980’s failed, but the technology has advanced and become more reliable and robust since then.

USDA grants, loans, and loan guarantees may be available for financial assistance. See www.rurdev.usda.gov/rbs/farmbill/index.html and www.rurdev.usda.gov/rbs/coops/vadg.htm. EPA and DOE also occasionally offer grants or other incentives. Check the Intermountain CHP Center website for current information on grants and incentives.

For more information, visit the following websites:

© 2006 Southwest Energy Efficiency Project
2260 Baseline Road, Suite 212, Boulder, CO 80302
(303) 447-0078 fax: (303) 786-8054 info@swenergy.org