Geothermal bore drilling at a rural home. (Photo by jeffreyw via Creative Commons)

Iowa is a national leader in wind energy, with the second most installed capacity after Texas.

A bill signed into law this spring aims to help diversify the state’s renewable sources beyond wind, offering among other things a first-ever state tax credit for geothermal projects.

Geothermal installers say the incentive is already helping to sway motivated customers who have done their homework but hesitated to make the investment until now.

“Everyone’s been darn busy putting geothermal in,” said Ron Marr, executive director of the Iowa Geothermal Association, which represents about 150 installers.

Geothermal systems tap into the near-constant temperatures found deep enough below the surface all year round, usually between 50 and 60 degree Fahrenheit. In the winter, water or fluid is pumped through a system of underground pipes, carrying heat up to the surface. In the summer, the system reverses, depositing heat below ground. →