Alternative energy for Hill AFB

LAYTON — Davis County has a small energy field that's being tapped to supply steam and electricity for Hill Air Force Base.

The Wasatch Integrated Waste Management District, immediately east of Hill, has about 3 million tons of garbage that is decomposing and turning into methane gas. Methane gas readily burns and if it isn't flared off or dumped into the atmosphere, it can build up and cause a stink for neighbors, particularly the folks in nearby South Weber City, as well as being an explosive hazard.

The district's landfill, east of Hill Air Force Base and north of Highway 193, collects garbage from most of Davis County, and as it decomposes, it produces methane, which also is considered a greenhouse gas.

Three years ago the district dug deep wells into the landfill to collect the methane. It was piped to a collection station where it was pressurized and flared off so it wouldn't accumulate and pose an explosive risk. A few years ago a scale house at another landfill in Salt Lake County blew up, apparently after a worker lit a cigarette.

"Now, instead of flaring the gas, we're cleaning it up by removing the moisture and particulates in it and shipping it to Hill Air Force Base to produce electricity," said Nathan Rich, executive director of the Wasatch District. The gas, as it comes from deep in the landfill, contains quite a bit of moisture that is removed by chilling it, and filters take nearly all of the microscopic dirt particles out of it.

It is pumped at 7 to 9 pounds per square inch through 10,000 feet of pipe to a new complex on the Hill property that contains two Caterpillar engines that have been modified to burn methane.

The engines drive generators that produce 800 kilowatts and 600 kilowatts of electricity that is put back on the Utah Power grid. Utah Power pays Hill about 3 cents per kilowatt hour for the power under a public law that allows power producers to put electricity on the grid and get paid for it.

The air base puts the power on the grid rather than using it on base, primarily because of convenience and the cost savings of having to run power lines from the generators to various buildings on base. "They're putting the power back on the grid because all of their equipment is connected to Utah Power meters, so it's easier to push it back on the grid and not have to rewire and build switches," Rich said.

The two generators are producing slightly under capacity at about 1 megawatt on average, which is enough power for 700 homes on a continuous basis, Rich said. The generator building has space left for another generator.