The Rise of Low-Temperature Geothermal Energy
Low-temperature geothermal resources, typically below 300°F (150°C), have emerged as a promising solution for sustainable thermal energy management in industrial processes. These resources can meet a wide range of energy needs, from heating and cooling to direct-use applications in industries like paper drying, greenhouses, and even beer brewing.
The Geothermal Technologies Office’s (GTO) Low-Temperature and Coproduced Resources program has been at the forefront of research, development, and demonstration (RD&D) activities, focusing on improving the efficiency of low-temperature geothermal systems and expanding their utility through additional revenue streams. This includes the extraction of valuable critical materials like lithium from geothermal fluids.
One of the key advantages of low-temperature geothermal energy is its ability to contribute towards the goal of reducing the carbon footprint of the U.S. building stock by 80% by 2035. These resources can be utilized by a diverse range of community customers, including urban centers, rural areas, and remote communities.
Reservoir Thermal Energy Storage (RTES)
An innovative application of low-temperature geothermal energy is Reservoir Thermal Energy Storage (RTES). This technology takes advantage of large storage capacities, geothermal gradients, and thermal insulation in the subsurface to store thermal energy directly in underground reservoirs. This stored energy can then be extracted for use in various industrial processes, such as concrete or chemical production, lumber drying, and textile manufacturing.
By using RTES to provide the heat needed in these energy-intensive industries, significant emissions reductions can be achieved. The ability to store thermal energy for 100 or more hours and then utilize it as needed makes RTES a highly efficient and sustainable solution for industrial heating requirements.
Direct-Use Geothermal Applications
One of the most common direct-use geothermal applications is geothermal district heating, where hot water is piped directly from underground heat sources into heat exchangers or buildings. The oldest geothermal district heating system in the United States is in Boise, Idaho, and has been in operation since the 1890s.
Beyond district heating, direct-use geothermal applications include:
- Greenhouses: Utilizing geothermal heat to maintain optimal growing conditions.
- Aquaculture: Providing a stable, temperature-controlled environment for fish and other aquatic species.
- Food processing: Drying agricultural products, brewing beer, and other heat-intensive food processing activities.
- Industrial uses: Processes that require significant process heat, such as pulp and paper production, cement drying, and lumber drying.
These direct-use applications demonstrate the versatility of low-temperature geothermal resources in meeting the thermal energy needs of a diverse range of industries.
Hybrid Geothermal Systems
Geothermal energy can also be harnessed in combination with other clean energy technologies, creating hybrid systems that enhance efficiency and expand the use of renewable thermal energy. The GTO supports research and development to explore the potential of these hybrid systems, including:
- Solar-geothermal hybrid systems: Integrating solar thermal or photovoltaic technologies with geothermal resources to optimize energy production.
- Reservoir Thermal Energy Storage (RTES) hybrid systems: Combining RTES with other technologies to provide a comprehensive solution for industrial heating and cooling needs.
These hybrid approaches leverage the strengths of different renewable energy sources, creating synergies that can lead to more efficient and cost-effective thermal energy management solutions for industrial processes.
Case Studies: Harnessing Low-Temperature Geothermal Energy
To illustrate the practical applications of low-temperature geothermal energy, let’s explore a few case studies:
Case Study 1: Geothermal District Heating in Boise, Idaho
The city of Boise, Idaho, has been harnessing the power of low-temperature geothermal resources since the 1890s, making it home to the oldest geothermal district heating system in the United States. The system utilizes hot water from underground aquifers to provide heating for over 6 million square feet of commercial, residential, and government buildings in the downtown area.
This sustainable heating solution not only reduces the city’s carbon footprint but also provides a reliable and cost-effective source of thermal energy for the community. The system’s longevity and continued operation demonstrate the long-term viability of low-temperature geothermal district heating systems.
Case Study 2: Geothermal Heating and Cooling for a Greenhouse in Klamath Falls, Oregon
In Klamath Falls, Oregon, a local greenhouse operation has successfully integrated low-temperature geothermal energy to meet its heating and cooling needs. The greenhouse utilizes the stable, year-round temperature of the underground geothermal resource to maintain optimal growing conditions for a variety of plants and crops.
By harnessing the geothermal energy, the greenhouse has been able to significantly reduce its reliance on traditional fossil fuel-based heating and cooling systems, leading to substantial cost savings and a smaller environmental footprint. This case study demonstrates the versatility of low-temperature geothermal resources in supporting sustainable agricultural practices.
Case Study 3: Geothermal-Powered Beer Brewing in Chena Hot Springs, Alaska
In the remote community of Chena Hot Springs, Alaska, a local brewery has found an innovative way to utilize low-temperature geothermal energy in its beer production process. The brewery taps into the hot springs to provide the necessary thermal energy for various stages of the brewing process, including mashing, boiling, and pasteurization.
By harnessing the geothermal resources, the brewery has been able to reduce its reliance on conventional energy sources, leading to cost savings and a more sustainable production process. This case study highlights the potential for low-temperature geothermal energy to support local industries and communities, even in remote and challenging environments.
Conclusion: Embracing the Potential of Low-Temperature Geothermal Energy
As the demand for sustainable and renewable energy solutions continues to grow, low-temperature geothermal energy has emerged as a promising and versatile option for industrial thermal energy management. From RTES to direct-use applications and hybrid systems, the opportunities to harness the power of these resources are vast and can contribute significantly to reducing the environmental impact of energy-intensive industries.
The case studies presented demonstrate the real-world success stories of leveraging low-temperature geothermal energy, showcasing its ability to support diverse industrial processes, enhance energy efficiency, and foster more sustainable communities. As the technology and research in this field continue to evolve, the potential for low-temperature geothermal energy to transform the industrial landscape is undeniable.
To learn more about the latest developments and funding opportunities in low-temperature geothermal energy, be sure to subscribe to the GTO e-newsletter. Stay informed and join the movement towards a more sustainable future for industrial thermal energy management.
