Geothermal Questions Answered with Geothermal Top Questions & Answers – FAQs for Geothermal Systems
Geothermal Questions Answered with Geothermal Top Questions & Answers – FAQs for Geothermal Systems
Frequently Asked Questions About Geothermal Energy
What is Geothermal Energy?
Answer: Geothermal energy is heat (“thermal”) derived from the earth (“geo”). It is the thermal energy contained in the rock and fluids, that fill the fractures and pores in the rocks that form the earth’s crust.
How does geothermal heat get up to the earth’s surface?
Answer: The heat from the earth’s core continuously flows outward. It transfers (conducts) to the surrounding layer of rock, the mantle. When temperatures and pressures become high enough, some mantle rock melts, becoming magma. Then, because it is lighter (less dense) than the surrounding rock, the magma rises (convects), moving slowly up toward the earth’s crust, carrying the heat from below.
Sometimes the hot magma reaches all the way to the surface, where we know it as lava. But most often the magma remains below earth’s crust, heating nearby rock and water (rainwater that has seeped deep into the earth) – sometimes as hot as 700 degrees F. Some of this hot geothermal water travels back up through faults and cracks and reaches the earth’s surface as hot springs or geysers, but most of it stays deep underground, trapped in cracks and porous rock. This natural collection of hot water is called a geothermal reservoir.
Why is geothermal energy “environmentally friendly”?
Answer: Unlike coal-fired and natural gas-fired power generation plants, the state of the art geothermal binary cycle plant produces virtually no emissions. When compared to natural gas, a 100 MW geothermal power generator offsets 190,000 pounds of nitrogen dioxide and sulfur dioxide per year. Additionally, it eliminates 780 million pounds of CO2 emissions. The reduction in emissions, when compared to coal-fired plants, is even greater. The binary cycle technology was pioneered at Raft River, Idaho in the early 1980s.
Why is geothermal considered a renewable energy resource?
Answer: All types of geothermal energy are renewable as long as the rate of heat extraction does not exceed the rate at which the thermal reservoir it depends upon is renewed by heat from the earth’s Magna. Geothermal reservoirs that tap the earth’s heat for energy production typically have 30 to 50-year life as the plant’s equipment wears out. Indeed, the world’s first geothermal power plant at Larderello, Italy was commissioned in 1913 and is still producing. The Geysers, California facility has been in production since the early 1960s.
Does technology exist to extend reservoir life?
Answer: Yes, in particular with binary plants since the water produced from the fracture system can be re-injected back into the fracture system and reheated by the source rock. Currently, Calpine’s, the owner of Geysers, is constructing a $163 million, the 41-mile pipeline to move the effluent water from the City of Santa Rosa’s sewage system for injection into the geothermal reservoir. The Raft River property of US Geothermal Inc. (“USGEO”) will involve a binary system to save and re-inject water back into the fractures for reheating. The scheduled reservoir modeling will identify where to position injectors for the maximum benefit.
Why has there not been greater development of U.S. geothermal capacity?
Answer: The development of geothermal power through the 1990s has been impeded by two factors: location and cost. In respect of location, most geothermal reservoirs are located in the Western States and specifically in areas which enjoyed excess electrical capacity. For example, Raft River in Idaho and the Newberry Caldera in Oregon are within the Bonneville Power Authority (BPA) system, which distributes hydropower from the Columbia River dams. Local electrical distributors like Idaho Power and Pacific Power could service their clients by purchasing from the BPA the lowest-cost electricity in the USA.
In respect of costs, prior to recent technological advances, the cost of developing geothermal reservoirs, building generators and operating them was between 6 cents and 8 cents per kilowatt-hour (Kwh). The major sources of new electrical power generation in the 1990s and until recently was coal and natural gas. These sources were competitive in the 4 to 6 cent per kWh range.
- 30% of total system cost in 2022 through 2032
- 26% of total system cost in 2033
- 22% of total system cost in 2034
- No limit to credit amount
- Can be used to offset alternative minimum tax (AMT)
- Can be used in more than one year
- Can be combined with solar and wind tax credits
- Can be combined with energy efficiency upgrade credits
What’s Eligible: Geothermal equipment that uses the stored solar energy from the ground for heating and cooling and that meets ENERGY STAR requirements at the time of installation is eligible for the tax credit. Covered expenditures include labor for onsite preparation, assembly, or original system installation and for piping or wiring to connect a system to the home. The structure must be located in the United States and used as a residence by the taxpayer, although primary residency isn’t required. In fact, if geothermal is installed in more than one home, there’s no limitation on the number of times the credit can be claimed.
What’s Not: The credit can’t be claimed for spending on equipment used solely for hot tub or pool conditioning, nor on previously used equipment. Rental home installations also cannot be claimed. As of November 2013, electric strip heat and ductwork distribution systems are no longer included in the tax credit calculation.
How to Claim the Credit: Use IRS Form 5695 to claim the Residential Energy Efficient Property Credit, and there’s no limit on the credit amount. The tax credit can be used to offset both regular income taxes and alternative minimum taxes (AMT). If the federal tax credit exceeds tax liability, the excess amount may be carried forward into future years. Spending on geothermal heat pump property adds to your home’s cost basis but also must be reduced by the amount of the tax credit received.
Learn more about offers and rebates.
Geothermal Resource Council, www.geothermal.org Where can I find more information on geothermal resources, specifically electrical generation?
Answer: Some excellent sources of information include:
- Geothermal Energy Association, www.geo-energy.org
Can We drill in Wintertime?
Answer: Yes, Boreholes can be drilled even when the ground is frozen solid.