Ultra Geothermal, Inc., of Barrington, N.H., scoffs at the notion that geothermal energy is only for hot springs and volcanoes, and they can back this up with over 700 geothermal installations in the New England area. In fact, with a ground temperature of around 50 degrees F, geothermal energy in New Hampshire can heat your home in the winter, air-condition it in the summer and supplement your hot water without directly burning any fossil fuels. According to Ultra Geothermal's President Melissa Aho, geothermal energy reduces your fuel costs by around 50 percent and improves the air quality in your home creating a hypoallergenic environment. Switching to geothermal could save you $1,530 per year and reduce your carbon footprint to only the electricity needed to run the system.
A geothermal home heating system works similarly to a refrigerator. A refrigerator will use a series of coils to remove the heat from the food you put inside of the refrigerator and displace it to the room outside. Essentially a geothermal system works in same way but by removing the more abundant heat from the earth and displacing it into your home. A system of pipelines buried hundreds of feet into the earth pumps up water at ground temperature (50 degrees). This circulates around a refrigeration coil that picks up this heat to be compressed down and then expanded to an air temperature of 85 to 90 degrees to heat your home. The process can be reversed in the summer using the ground as a sink for heat instead to provide air conditioning for your home.
Aho does admit that New Hampshire provides a unique challenge to geothermal energy; our New England ground is rife with slabs of granite, boulders and rock ledges, which makes drilling wells for the pipelines more difficult but not impossible.
The second drawback to geothermal energy is that its startup cost is expensive and payback periods can be in excess of 15 years. The system itself costs $20,000-$25,000 for a 2,500 square-foot home. The price of the system does not stand alone because a well capable of sustaining geothermal energy is needed (the in ground pipes collecting the earths heat) and can cost around $10,000. This makes retrofitting a house already on the town's water system and without air ventilation heating (also needed for geothermal) very costly. However, tax credits can defray these costs with a 30 percent uncapped federal incentive and a capped $7,500 Public Service of New Hampshire award to make geothermal more affordable. Building a new home that already needs a well for domestic water can make the up front expenses of geothermal more practical.
There is an immense clean power beneath our feet, and some estimates even suggest that it is double what humanity's current energy consumption requires. But the technology is lagging to make "geo" practical on a larger scale and drilling for electric production staggers in the millions. However, geothermal for home heating is increasingly becoming more common and affordable, and as technology advances I have no doubt this can be applied on a larger scale. To learn more, check out Ultra Geothermal, Inc.'s website
or this great New York Times article
about large scale geothermal.