Archaeological evidence shows that the first human use of geothermal resources in North America occurred more than 10,000 years ago with a settlement around hot springs.
While people still soak in shallow pools heated by the earth, engineers have developed technologies to access geothermal energy miles beneath the earth’s surface.
According to the Geothermal Energy Association, 39 countries could supply all of their electricity needs from this type of energy, yet only 6 percent of the world’s potential geothermal power has been tapped.
Northbrook’s Climate Action Plan found that building energy use is the largest part of our carbon footprint, and geothermal energy could dramatically reduce that footprint.
Geothermal energy is clean, renewable, reliable, abundant, and available 24 hours a day, 365 days a year. While the initial drilling can be expensive, the heat source itself is free.
There are three main methods:
Ground source heat pumps, direct use of hot groundwater, and deep systems using steam from far below the earth’s surface.
Ground source heat pump systems are the most relevant for building owners and developers in Northbrook.
How does it work? It’s simple. The ground twenty feet below the earth’s surface maintains a constant 50 degree temperature – higher than average winter temperatures, and lower than average summer temperatures.
Ground source geothermal uses this difference in temperature to transfer heat between a building and the earth with a heat pump and a pipe system. During the summer, the system draws in heat from the air in the building and transfers it to the ground. During the winter, it draws heat from the ground and transfers it to the building.
Geothermal is ideal for new construction, with a rapid payback of initial costs, long term savings, and a product life span substantially longer than conventional fossil fuel systems. It is also practical for retrofitting existing buildings.
There are many programs that help make geothermal affordable. Homeowners receive a 26 percent federal tax credit for installing these systems, and businesses receive a federal tax deduction. ComEd provides thousands of dollars of discounts for both installing and replacing them. Both the Illinois Finance Authority and Cook County are possible sources of direct funding for geothermal energy projects.
Every building is a candidate for planned conversion to clean energy, and geothermal may be the best clean energy option for most. Go Green Northbrook encourages all Northbrook residents, businesses, non-profits, and governmental agencies to consider using it.
gogreennorthbrook.org 