Richland, Wash.-Based Utility Mulls Cow Power
Dec. 26-Energy Northwest is at a crossroads with its pilot project that turns cow dung into kilowatts.
After the energy utility sank about $750,000 in equipment and staff time into its setup at a Franklin County dairy near Pasco, tests suggest the facility could produce as much as twice the power that traditional biogas digesters have.
The problem is, that's still not enough to drive the price per kilowatt-hour down to a competitive level.
"People will pay a little extra for green power, but not a lot extra," said Dan Porter, a project manager for Energy Northwest. The public power consortium operates the nuclear plant north of Richland, a solar plant at the nuclear site and the wind farm south of the Tri-Cities.
The utility is awaiting a review from a Washington State University microbiologist before deciding whether the technology is commercially viable.
Generators fueled by methane extracted from dairy waste haven't yet produced power cheap enough to be viable in the Northwest, where electric rates still are among the nation's lowest despite drastic increases in the past four years.
How much power can be produced determines how much that power will cost. At best, traditional setups that have processed solid dairy waste have managed to generate 0.2 kilowatts per cow.
Energy Northwest had hoped the system it has been testing, developed by Kennewick's Soil Search LLC, would produce 1 kilowatt per cow. That system, set up at Franklin County's 5D Farms, extracts solids and sucks methane from a giant lagoon of manure-laced water covered by a polyvinyl blanket.
The lagoon can be heated to stimulate methane production and the blanket keeps the methane from escaping. Based on readings taken over the past year, Energy Northwest believes the system could generate between 0.3 kilowatts and 0.5 kilowatts per cow.
That's a far cry from the initial target but a substantial improvement over other technologies.
"We set some pretty ambitious goals," said Energy Northwest spokesman Brad Peck. "I don't want to leave you with the impression we're disappointed. We feel pretty good about how much we've learned."
Others may consider it a significant step toward commercial viability, but Energy Northwest was hoping to make that jump entirely.
"We want to arrive at a product that we can deploy broadly," Porter said. "Biomass, we think, is close to being in the money. We need a breakthrough."
What's left to be seen is how much potential utility customers would be willing to subsidize a dairy waste generator, and whether farmers would be willing to chip in to compensate for the odor reduction the system provides.
A key finding learned in operating the facility was that ongoing dairy operations can't be disturbed. Those operations can affect an array of variables that could negatively modify the waste stream -- things such as what cows are fed, what their bedding consists of and how frequently waste is washed into the lagoon.
For now, Energy Northwest is simply venting the methane being produced at 5D Farms while it reviews its findings and decides what to do. A decision may yet be several months out.
"We learned a tremendous amount but we didn't get there," Porter said of the methane production levels achieved at the site. "The nut we have to crack is 'is that good enough?' "
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