- The Washington Times - Thursday, January 24, 2002

Alternative energy can be drawn from flowing rivers, gusting winds or the steady beat of the sun.
It also can be derived from less appealing sources, like the waste products of chickens, pigs and cows.
The technology that transforms various manures into energy has existed since the 1970s, according to the Environmental Protection Agency, but recent indications are that both power companies and some animal farms are looking at manure as an untapped source of energy for the new century.
The Agstar program, a voluntary effort sponsored by the EPA and the U.S. departments of Agriculture and Energy to promote the recovery and use of methane from animal waste, reports that about 50 "digester" systems are operating across the country, about half at swine farms. The rest mainly involve dairy farms.
The participating farms stopped more than 5,800 metric tons of methane last year from escaping into the atmosphere.
Jeff Corbin, senior scientist with the Chesapeake Bay Foundation, says using manure for power production is more than another way to generate electricity. It helps preserve the environment.
Part of the environmental problem, locally, is that about 80 percent of Virginia's poultry industry is concentrated throughout half a dozen counties in the state's Shenandoah Valley, typically abutting freshwater streams.
The algae in those streams feeds on phosphorus, found in great quantities in chicken manure and less so in other manures. When too much phosphorus-rich manure makes its way into the soil, the nutrients seep through to nearby streams and overload them with phosphorus.
If the river turns green with aggressively growing algae, it prevents sunlight from reaching the underwater grass.
"If [the algae] sink to the bottom, they suck up oxygen as they break down," Mr. Corbin says. Either way, the ecosystem is damaged.
Some farms transport excess manure to other farmers in need of natural fertilizer, but transportation costs quickly climb, making these transfers less economically viable.
The technology that makes energy from manure, dubbed a methane digester, takes manure that has been collected and pumps it into a concrete, air-tight vessel with a flexible membrane top.
The manure is heated to about 95 degrees, which allows the anaerobic bacteria bacteria that can live and grow without oxygen to feed on the waste. It takes from a couple of weeks to a month for the bacteria to break the manure down into tiny particles of sugar, hydrogen and organic acids.
A second batch of anaerobic bacteria introduced into the chamber feasts on the acids and hydrogen, creating a biogas blend of about 60 percent methane and 40 percent carbon dioxide. This gas rises to the top of the chamber and easily can be siphoned away. It then enters a natural gas engine generator modified for methane, which turns it from mechanical energy to electrical energy. According to a description of the process by Associated Press, the electrical energy is sent to the power grid through transformers installed on nearby power poles.
The remaining byproduct, such as fiber, can be sold as nursery fertilizer, since it retains many of its nutrients.

Dina Kruger, chief of the methane and sequestration branch which runs Agstar, says using animal waste to produce energy fizzled initially, partly due to overzealous planning and technology that some farmers viewed with suspicion.
Interest in the process resurfaced in the late 1980s, and Agstar emerged in 1993 to help connect farmers with the information needed to begin the process.
Although the U.S. approach to methane digester technology is a wary one, China and Europe are two regions that embrace the process more readily.
Electricity created by such methods can be used to run milking machines, or the fuel can provide the farm's heating and cooling needs. Excess electricity can be sold to power companies.
Creating energy through animal waste is considered green power, a renewable energy source that cuts down the release of methane gas into the atmosphere.
The process isn't cheap, though. Ms. Kruger estimates that the cost of a methane digester system can start at $100,000 and go up to $500,000, depending on the project's size.
Beyond the economic downside, Mr. Corbin says, the process has the potential for nutrient emission from the smokestacks. Also, the ash byproduct contains a high concentration of phosphorus, but its volume is greatly reduced and the remaining material can be sold as fertilizer.
In addition, methane digestion does not produce a consistent supply of methane, says Barry Kintzer, a national environmental engineer for the Natural Resources Conservation Service, a section of the U.S. Department of Agriculture that helps people conserve, maintain, and improve the environment.
The volume of methane produced varies based on how quickly the bacteria feeds on the manure and the temperature. It takes more energy to keep the temperature at about 95 degrees, and the equipment can break down, causing delays.
Mr. Kintzer estimates that it costs twice as much to generate electricity with manure instead of through conventional means. The costs to a company can be less if they take advantage of government subsidies meant to encourage these projects, he says.
The process does reduce methane emissions, which are considered greenhouse gases. It also reduces odor while stabilizing nutrients.
Such flexibility in dealing with manure appeals to chicken plant companies, says Richard Lobb, spokesman for the National Chicken Council, based in the District. The group promotes chicken consumption and represents the chicken industry in Washington.
"In some places, its still an option to use it as fertilizer," says Mr. Lobb.

Another way to treat manure is gasification. Tyson Foods of Springdale, Ark., is one company using this method.
The chicken giant is collaborating with Renewable Energy, an Australian firm with offices in Charlotte, N.C., to use up to 85,000 tons of chicken litter a year to generate steam at its Temperanceville, Va., poultry processing plant.
The $12 million gasification facility will take chicken manure and sludge from Tyson's wastewater treatment plants in Temperanceville and Berlin, Md. That will reduce the amount of excess manure to be relocated to neighboring lands.
When completed, two adjacent gasification plants will produce 120,000 pounds of steam per hour to be used in Tyson's protein conversion plant to help power the plant that stands next to the poultry processing plant.
The gasification process, like the electricity-generating plants, "provides independent farms with an alternative use for their litter," says Ed Nicholson, director of media and community relations for Tyson Foods.
Gasification produces a nutrient-rich ash that can be sold to fertilizer manufacturers.

Mr. Nicholson sees alternative energy methods as a trend, one that farmers will turn to over time.
While poultry plants may see the process as a way to generate power while being environmentally friendly, power companies take a harder look at the bottom line.
Conectiv, a Newport, Del., power company, considered spending $50 million to refit its Vienna, Md., power plant to burn poultry litter. The company estimated it could burn about 400,000 tons of litter a year to power about 20,000 homes, but the project fell through when the company sold that power plant to NRG Energy.
Others electric companies, such as Dominion Power of Richmond, have no plans to incorporate methane digestion to create electricity through their plants.
Glenn Simpson, vice president of Pepco Energy Services, a subsidiary of the District's Potomac Electric Power Co., says his company discussed building a methane digestion plant near the Delmarva Peninsula in cooperation with England's Fibrowatt Energy Group, an international developer of electricity power stations fueled by biomass. That plant would have used chicken manure to create electricity, with Fibrowatt owning and operating the facility and Pepco buying the power, but the cost of buying the electricity was more expensive than to generate electricity by standard means.
Electricity, at the moment, is less expensive in the United States than in a country such as England, where such alternative energy applications are in place, Mr. Simpson says. That makes manure-based energy less viable for electric companies.
With reservations, Mr. Simpson sees renewable energy as an industry customers will be interested in.
"Whether or not manure-to-electricity is going to be a large percent of it, it's hard to tell," he says.


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