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Bainbridge turns to geothermal heat amid high energy prices
With a steady groan, a six-inch diameter mud drill began chewing into the yard of a Grand Avenue home this week.
The drill would grind through layers of sediment, pulverize rock and perhaps pierce several aquifers before reaching 300 hundred feet below ground.
It wasn’t drilling for water, it was mining for heat.
Three hundred feet below ground, the temperature is a constant, balmy 58 degrees. When harnessed, that consistent geothermal energy can make home heating and cooling systems 30 to 70 percent more efficient.
It’s not a new technology, but with the recent spike in fuel prices driving up utility bills, homeowners seem to be warming up to the option.
Gerard Maloney, whose Duvall-based company Earthheat is installing the system on Grand Avenue, said demand has been rampant in the Northwest this year, and he has received a number of inquiries from Bainbridge and Vashon Islands.
When he began specializing in the geothermal field 11 years ago, Maloney said he may have installed 10 heat pumps for geothermal systems in a year. Already this year he has installed more than 30.
“In the last three months especially, it has been unprecedented,” Maloney said.
Geothermal systems take a large yard and a hefty initial investment to install.
They cost 20 to 50 percent more than conventional systems and range from $12,000 to $40,000 depending on the size of building and the number of heat pumps needed.
According to Maloney geothermal systems of all sizes usually pay for themselves in five years of energy savings.
Once installed, the systems can last for more than 100 years.
The longevity has made geothermal an appealing energy source for institutions, including schools, military bases, churches and government buildings. This month Seattle’s Woodland Park Zoo is installing a geothermal system to help keep its penguin exhibit cool.
Recent fuel prices are making geothermal increasingly affordable for homeowners.
Zbigniew Pomykala, owner of the Grand Avenue house, said he discovered the technology by coincidence.
Earthheat was already working on radiant floor heating in the house, and he was intrigued by the company’s geothermal systems.
Pomykala had been considering other forms alternative energy for his home, but saw solar and wind generators as too unreliable.
“I started doing a lot of my own research and realized that in our Seattle climate, this (geothermal) is the most reliable renewable energy source,” he said.
For Pomykala, who lives in Chicago but plans to retire on Bainbridge soon, renewable energy is more than a hobby. He believes the U.S.’s reliance on imported fossil fuels has made it vulnerable, and would like to see a focus on domestic energy production, even at the household level.
So this week Redmond-based Gregory Drilling was at work tapping holes for Pomykala’s new heating system.
Guided by a truck-mounted derrick, the rotary mud drill burrowed five narrow holes, each 300 feet deep, an industry standard, according to driller Chris Gregory.
Two lengths of black plastic pipe joined by a U-bend were threaded down into the shafts and cemented in place with betonite grout compound.
The grout acts as a heat transfer between the earth and pipe, and per state requirements, seals up any aquifers punctured by the drill Gregory explained.
“We may hit three or four aquifers drilling down,” Gregory said. “What you don’t want is the aquifers to communicate and contaminate each other.”
When the system is working, water mixed with anti-freeze is pumped down the pipes, where it warms to over 50 degrees before cycling to the surface. Heat pumps draw from that conistent temperature, rather than the constantly shifting outside air, making them more efficient for both heating and cooling.
The five shafts at Pomykala’s house will produce roughly 70,000 BTUs according to Maloney, and the system will cost roughly $700 in electricity each year to operate.
Pomykala said he saw the high installation cost of geothermal as an investment in sustainability.
“Ultimately this house will be inherited by my children,” Pomykala said. “I can’t think of giving a better gift than a home that is nearly energy independent.”
t Island home is among a growing number now switching to geothermal energy for their heating and cooling systems.