There’s been a shift in society’s focus regarding green energy alternatives. Green energy may solve current climate change issues and high utility costs from solar power to wind turbines. If we can all work to reduce our carbon footprint, the planet will be better off in the long run. Another type of energy technology being used to help accomplish this goal is geothermal technology. It harnesses heat from below the earth’s surface, heating and cooling residential and commercial buildings.
Here are some of the ins and outs of geothermal technology, the types of geothermal power plants that exist, and how these systems work.
Types of Geothermal Power Plants
Typically, geothermal plants use steam to produce electricity. Steam is produced from reservoirs of hot water beneath the earth’s surface. Tapping into this underground resource can help power homes and businesses in the surrounding areas.
Because geothermal energy is a step in the right direction to combat climate change, the government offers tax incentives to help bring us closer to a greener energy system.
Below are the three types of geothermal power plants that exist today.
1. Flash Steam
Flash steam power plants are the most common type. The reservoirs that produce the hot steam reach temperatures up to 360 F. Hot water flows upward under its pressure.
As the water level rises, the pressure decreases and creates steam. This is used to power a turbine or generator, which can then heat or cool a building. Excess steam returns down into the reservoir to be used again — that is why this energy source is sustainable.
2. Binary Steam
Binary steam power plants operate on the water with a lower temperature of about 225-260 F. Because of this, not enough steam is produced to generate electricity.
The heat from the hot water is used to boil a working fluid that typically has a low boiling point. Once the liquid is vaporized in a heat exchanger, it’s used to power a turbine. Water and working fluid in a binary cycle system are never combined, so little to no air emissions are released.
3. Dry Steam
Steam in a dry steam power plant travels directly through the earth’s surface and is directed to a turbine or generator unit. Currently, the only known dry steam resources are located in the geysers in northern California and Yellowstone National Park in Wyoming.
Geothermal Heating and Cooling Modes
Amazingly, geothermal energy can be used for heating and cooling residential and commercial buildings. Here’s how geothermal heating and cooling works.
Here is the process for how the steam from the earth’s surface can be used to heat a building:
- Circulation: An above-ground heat pump moves water or another working fluid through a group of buried pipes or loops of pipes.
- Heat absorption: When the fluid passes through these pipes, it absorbs heat.
- Heat exchange and use: Heated fluid returns to the building and passes through a heat exchanger before entering the structure’s existing air system
- Recirculation: After the fluid transfers back to the building, its temperature lowers and returns to its original starting point to be heated again.
Here is the process for how the steam from the earth’s surface can be used to cool a building:
- Heat exchange and absorption: Water or a working fluid absorbs heat from inside the building and is put through a heat exchanger, similar to how an air conditioner works.
- Circulation: The heat pump moves the fluid through the set of buried pipes underground.
- Heat discharge: Heat is absorbed by the underground area around the pipes, cooling off the fluid.
- Recirculation: The final step includes the fluid reentering the building at a lower temperature. It will begin the heat exchange process again.
Geothermal energy technologies can revolutionize the energy industry. More research is being done in the field of geothermal energy, which means within the next few decades, it could be more commonplace for residents and businesses to adopt this new tech.
Cost of Geothermal Energy Sources
No set price can be determined, mainly because the size of a home and the pipes needed to set up these systems vary. Generally speaking, a small house or office building may only cost anywhere from $10,000 to $25,000.
All these factors play a role in determining the cost of geothermal heating or cooling systems:
- Soil conditions
- Plot sizes
- Site accessibility
- System configuration
- Amount of digging and drilling required for installation
The initial, upfront costs associated with geothermal technology may seem intimidating at first, but it’s rare for residents to pay the full sticker price. On top of that, there is a 26% federal tax credit.
Geothermal Energy Use in the Future
This geothermal energy technology will likely become more popular soon. As it continues to develop, more homes and commercial buildings will adopt geothermal heating and cooling systems for cost savings and to reduce our carbon footprint.