Can This Cow Produce 2900 kW A Year?

Miles per Gallon? With the biofuels industry taking off, you may hear that term less and less. The need to make cellulosic ethanol more efficient has coined the phrase, "enzymes per gallon." Now, small-scale biomass generation has added another efficiency yardstick to the renewable energy lexicon: kilowatts per cow.

GHD, Inc., based in Chilton, WI, makes Anaerobic Digesters (AD), mainly for farms with a small-scale need for biomass power. Many of these farmers are just looking for a way to dispose of animal waste, reduce polluting runoff, and reduce odor. Of course, digesters can generate power too. GHD estimates that its digesters can put out 6-8 kilowatts/cow/day. In Wisconsin, a farm using GHD technology produced 1.5 million kW of electricity from 1,400 cows.

Today's biomass generators have a very use-every-part-of-the-buffalo mentality. GHD's ADs use methane for biogas, manure solids (lovely term) for bedding material, liquids become an odorless field fertilizer, and waste heat warms barns and heats water. GHD's digesters aren't picky eaters either. Their machines have been known to use for fuel anything ranging from fish trimmings and breading waste to cheese whey and sewage (which I believe is the recipe for a McDonald's Filet-O-Fish*).

NY-based AgriPower, Inc. is another upstart hoping to make it big in the microgeneration market. Their combined heat and power (CHP) generator is optimized for the little guy. Traditionally, farmers have to pay tipping fees to remove waste from their operations, even if that waste is going to a biomass energy facility. The unit's biggest advantage, as explained by Darren Ornitz , a Sales Associate with the company, "You are putting this on location. You are bringing this to where the biomass is." The company estimates that its unit can avoid $10-15 million in tipping fees over its useful life.

The company's 300 kW/hr system burns 5-10 tons of biomass per day. AgriPower says that for every 4 BTU's of fuel it takes in, it generates 3 BTUs of power in electricity and heat, making it 75% efficient.

Unlike GHD's digesters, the AgriPower unit burns biomass at nearly 2000 degrees F. These high temperatures mean a more complete combustion, resulting in fewer air pollutants and less than 1/2% ash content. It's so clean, you can run it indoors.

Ambient air running through pipes is heated by the combustion chamber then goes through the turbine. "It isn't coming into contact with the combustion air itself, so it's pure air, which means it can be used forcogeneration as well," says Ornitz . Not only that, this process reduces down-time because the cleaner air reduces wear and tear on the system. Less time for maintenance and repairs means lower operating cost.

The unit is also meant to be a replacement for farm-use diesel generators, but each unit will cost $1.2 million, a much more expensive proposition. However, Ornitz says, "with a diesel generator you're not only paying for the shipping of the fuel, but you're paying for the fuel itself. So you can make back that money in about 18 months."

In order to reduce downtime, the system uses air to air technology to separate the burn cycle from the turbine production cycle, reducing wear and tear on the system. The upshot is less downtime for maintenance and repairs.

The 16' by 40' unit weighs 40 tons, and is modular, so it can be easily transported. From the time it arrives, the mini power plant can be fired up in as little as 2 days. "You can even lift it with a helicopter. So the rural areas, you can get this to them," said Ornitz.

AgriPower is taking orders and hopes to ship the first units by the end of this year. The company sees opportunities worldwide in South America, Europe, and Asia. Soon, they may be taking orders of a different kind, from the U.S. Army, which has expressed interest in buying as many as 100 generators.

*Just kidding, please don't sue me. I love your fries.