Geothermal Offers Benign Energy Source

By CHARLES CHAVES/ecoRI News contributor

The number of American consumers considering renewable energy sources for space and water heating is on the rise amid Middle East geopolitical security concerns and expensive fuel prices. For example, it’s feasible to install geothermal systems as an economically viable alternative to costly heating oil. Utilizing appropriate technologies, it’s possible to install geothermal heat pump systems anywhere in the United States — even in cold climate areas.

Geothermal energy — meaning “heat from the earth” in Greek — is a clean, sustainable natural resource in North America and elsewhere. The geothermal resource base found everywhere in earth’s upper crust is immense, according to the Geothermal Energy Association. Yet, only a small fraction of this ubiquitous, domestic natural resource has been tapped to date in America.

However, the Geothermal Energy Association recently noted that the U.S. geothermal industry added about 90 megawatts of new capacity in 2011. This industry now has about 3,200 megawatts of installed generating power, more than every other country in the world. California ranks first in overall installed geothermal capacity, with about 2,615 megawatts already on line and nearly 2,000 megawatts in development.

There are four types of technology for geothermal heat pumps, according to the U.S. Department of Energy. Three kinds of installations are classified as closed-loop systems: horizontal, vertical and pond/lake; the fourth available model is called the open-loop system. Mitigating factors such as climate, soil conditions and land availability determine the type of geothermal system people install.

Geothermal heat pump technology can sustainably supply cooling and heating for water and living space for residential, commercial and public buildings. For example, North Providence this summer installed a geothermal system for heating and air conditioning purposes at its Town Hall. Department of Energy grants of $ 475,000 funded the 12 geothermal wells that were drilled in the parking lot behind Town Hall.

North Providence officials recently indicated that the geothermal system is working well, up to expectations. It’s estimated that the town will save at least $30,000 a year on energy and maintenance costs.

A conventional furnace or boiler consumes fuel to produce heat. In sharp contrast, geothermal heat pumps use electricity to transfer underground natural heat — thermal energy — into buildings. In cooling mode, however, they sink heat into the ground, thus reversing the process.

Since geothermal heat pumps don’t burn any fuel to operate, they cost-effectively supply consumers with hot water in addition to space heating and cooling. On average, a geothermal heat pump system costs about $7,500 for a typical residential size, minus installation expenses, according to the Department of Energy. Rebates, plus tax incentives, could lower the initial cost, however. Specifically, consumers looking to install geothermal heat pumps, or other renewable technologies, can receive a 30 percent federal tax credit with no upper spending limit for systems placed in service before Dec. 31, 2016.

Earth can sustainably supply humanity with abundant thermal energy. This ecologically benign natural resource has the potential to help meet growing demand for energy.  Geothermal systems present consumers with another decentralized clean energy technology option for hot water and space conditioning without burning expensive heating oil, which is largely imported.

To offset such foreign oil dependency, the expansion of geothermal heat pump installations would lessen oil imports and help stimulate the economy.