Thermal batteries are making inroads in the clean energy world.

[Sparty]

Thermal batteries are making waves in the clean energy world. They’re a promising solution to one of the biggest challenges in cutting carbon emissions: industrial heating.

Around 20% of global energy use goes into heating for industries like steelmaking, glass production, and food processing, and most of this energy currently comes from burning fossil fuels.

Thermal batteries offer a cleaner, cheaper alternative, and they’re gaining attention as a breakthrough technology that can store heat generated from renewable energy sources like solar or wind power, providing a clean way to meet these high-temperature demands.

Benefits of Thermal Batteries
Cheap and Abundant Materials: Unlike lithium-ion batteries, which rely on rare materials, thermal batteries use common substances like salt, graphite, and bricks.

Long-Duration Storage: They can store heat for hours or even days, making them ideal for industries that need constant heat.

Grid Support: By storing excess renewable energy, thermal batteries help reduce waste and improve grid stability.

Lower Emissions: They provide a cleaner alternative to fossil fuels, helping to cut carbon pollution from industrial processes.

list of thermal batteries currently in use or in pilot projects, along with the companies or organizations deploying them and their applications:

1. Rondo Energy
Technology: Modular heat storage using bricks (sensible heat storage).

Application: Industrial heat for food processing, chemicals, and cement production.

Current Use: Rondo’s thermal battery is being used at Calgren Renewable Fuels in California to provide heat for biofuel production.

2. Antora Energy
Technology: Carbon-based thermal storage (sensible heat storage).

Application: Industrial heat and power generation.

Current Use: Antora has demonstrated its technology in Fresno, California, and is scaling up commercial manufacturing in the U.S.

3. Brenmiller Energy
Technology: Crushed rock thermal storage (sensible heat storage).

Application: Industrial heat and power generation.

Current Use: Brenmiller’s bGen thermal battery is being used in Israel for industrial heat applications and grid energy storage.

4. Highview Power
Technology: Cryogenic energy storage (liquid air).

Application: Grid-scale energy storage and power generation.

Current Use: Highview has operational projects in the UK, including a 50 MW/250 MWh facility in Manchester.

5. Azelio
Technology: Molten aluminum thermal storage (sensible heat storage).

Application: Industrial heat and combined heat and power (CHP).

Current Use: Azelio has pilot projects in Sweden, Morocco, and the UAE for industrial and off-grid applications.

6. Kraftblock
Technology: High-temperature thermal storage using a composite material (sensible heat storage).

Application: Industrial heat and district heating.

Current Use: Kraftblock’s systems are being used in Germany for industrial processes and renewable energy integration.

7. Electrified Thermal Solutions
Technology: Solid-state thermal storage (sensible heat storage).

Application: Industrial heat and power.

Current Use: Pilot projects are underway in the U.S. for high-temperature industrial applications.

8. Terrapower (Molten Salt)
Technology: Molten salt thermal storage (sensible heat storage).

Application: Industrial heat and power generation.

Current Use: Terrapower is testing molten salt systems in the U.S. for industrial and grid applications.

9. 1414 Degrees
Technology: Silicon-based thermal storage (sensible heat storage).

Application: Industrial heat and power.

Current Use: Pilot projects in Australia and Europe for industrial heat and grid support.

10. CALMAC (Ice-Based Thermal Storage)
Technology: Ice-based thermal storage (latent heat storage).

Application: Space cooling and air conditioning.

Current Use: CALMAC’s systems are widely used in commercial buildings across the U.S. and globally for cooling.

11. Helen Oy (Finland)
Technology: Heat storage in tanks and rock caverns (sensible heat storage).

Application: District heating and peak shaving.

Current Use: Helen Oy operates large-scale thermal storage systems in Helsinki, Finland, to support district heating networks.

12. Polar Night Energy (Finland)
Technology: Sand-based thermal storage (sensible heat storage).

Application: District heating.

Current Use: Polar Night Energy has deployed a sand-based thermal battery in Kankaanpää, Finland, for district heating.

13. MGA Thermal (Australia)
Technology: Miscibility gap alloy (MGA) thermal storage (latent heat storage).

Application: Industrial heat.

Current Use: MGA Thermal is piloting its technology in Australia for industrial heat applications.

14. EnergyNest (Norway)
Technology: Concrete-based thermal storage (sensible heat storage).

Application: Industrial heat and power.

Current Use: EnergyNest has operational projects in Europe, including a thermal battery at a Siemens gas turbine plant in Italy.

15. Kyoto Group (Norway)
Technology: Molten salt thermal storage (sensible heat storage).

Application: Industrial heat.

Current Use: Kyoto Group is deploying molten salt thermal batteries in Norway and Spain for industrial heat applications.

16. Storworks (Netherlands)
Technology: Modular heat storage in hot rocks (sensible heat storage).

Application: Industrial heat and power.

Current Use: Storworks is piloting its technology in the Netherlands for industrial applications.

17. SaltX (Sweden)
Technology: Salt hydrate thermal storage (thermo-chemical storage).

Application: Seasonal heat storage.

Current Use: SaltX is testing its technology in Sweden for long-duration heat storage.

18. Fourth Power
Technology: Graphite-based thermal storage (sensible heat storage).

Application: Industrial heat and power.

Current Use: Pilot projects are underway in the U.S. for high-temperature industrial applications.

19. RedoxBlox
Technology: Thermo-chemical storage using redox reactions.

Application: Industrial heat and power.

Current Use: RedoxBlox is developing pilot projects in the U.S. for industrial heat and grid storage.

20. Magaldi (Italy)
Technology: Hot silicon thermal storage (sensible heat storage).

Application: Industrial heat and power.

Current Use: Magaldi is deploying its systems in Italy for industrial heat applications.

Summary
Thermal batteries are already being used in various industries and regions, from industrial heat in California to district heating in Finland and grid storage in the UK. Companies like Rondo Energy, Antora Energy, and Highview Power are leading the way, with many others scaling up their technologies for broader adoption. These systems are proving that thermal storage is a viable and scalable solution for reducing carbon emissions in industrial processes and energy systems.

[Sparty]

As of now, there isn’t a geothermal-powered thermal battery in the traditional sense, where geothermal energy directly charges a thermal battery system. However, geothermal energy and thermal batteries can complement each other in certain applications, and there are emerging ideas and projects that explore this synergy. Let’s break it down:

How Geothermal Energy and Thermal Batteries Could Work Together

Geothermal as a Heat Source:
Geothermal energy provides a constant, renewable source of heat from the Earth’s core. This heat could theoretically be used to charge a thermal battery, storing the energy for later use when demand is higher or when geothermal output is insufficient.

Hybrid Systems:
A hybrid system could use geothermal energy to generate electricity or direct heat, which could then be stored in a thermal battery for industrial processes, district heating, or grid stabilization.

Seasonal Storage:
Geothermal energy is consistent but may not always match demand. Thermal batteries could store excess geothermal heat during low-demand periods (e.g., summer) and release it during high-demand periods (e.g., winter).

Current Projects and Research
While there aren’t many geothermal-powered thermal batteries in operation yet, there are some related developments and concepts:

Geothermal District Heating with Thermal Storage:
In some geothermal district heating systems, excess heat is stored in large water tanks or underground reservoirs. While not a "thermal battery" in the strict sense, this is a form of thermal energy storage that complements geothermal energy.

Example: Reykjavik, Iceland, uses geothermal energy for district heating and stores excess heat in large insulated tanks for later use.

Geothermal and Molten Salt Storage:
Molten salt thermal storage, commonly used in concentrated solar power (CSP) plants, could theoretically be adapted to store heat from geothermal sources. This is still in the conceptual or research phase.

Geothermal-Powered Industrial Heat:
Some industries are exploring the use of geothermal heat directly for processes like drying, pasteurization, or chemical production. Thermal batteries could be added to these systems to store excess geothermal heat for later use.

Challenges
Temperature Mismatch: Geothermal heat is typically lower in temperature (around 150–300°C) compared to the high temperatures (500–1,000°C) required for many industrial processes. Thermal batteries designed for high-temperature storage may not be directly compatible with geothermal heat.

Infrastructure Costs: Integrating geothermal energy with thermal batteries would require significant infrastructure, including heat exchangers, pumps, and storage systems.

Location Constraints: Geothermal energy is location-specific, meaning it’s only viable in regions with accessible geothermal resources (e.g., Iceland, the U.S. West, East Africa, etc.).

Future Potential
The combination of geothermal energy and thermal batteries could be a powerful solution for:

Industrial Decarbonization: Providing clean, reliable heat for industries.

Grid Stability: Storing excess geothermal energy for use during peak demand.

Seasonal Heating: Storing geothermal heat in summer for use in winter.

While this concept is still in its early stages, ongoing research and pilot projects could make geothermal-powered thermal batteries a reality in the future. Companies and researchers in the geothermal and thermal storage sectors are likely to explore this synergy as both technologies mature.

[Sparty]

Seasonal Thermal Energy Storage (STES), such as the Varanto project in Finland, fits into the broader thermal battery space as a specialized application designed for long-duration energy storage. While most thermal batteries focus on storing heat for hours or days, STES systems like Varanto are designed to store heat for weeks, months, or even entire seasons. This makes them particularly valuable for balancing energy supply and demand over longer periods, especially in regions with significant seasonal variations in energy needs.

How Varanto Fits into the Thermal Battery Space
Purpose and Scale:

Varanto is a large-scale underground thermal energy storage system designed to store heat during the summer (when demand is low) and release it during the winter (when demand is high).

Unlike smaller thermal batteries used for industrial processes or short-term grid storage, Varanto focuses on seasonal energy storage, making it ideal for district heating systems and large-scale energy management.

Technology:

Varanto uses sensible heat storage, where heat is stored in a medium like water, rocks, or underground reservoirs. In this case, the heat is stored in large underground caverns filled with water.

The system captures excess heat from industrial processes, waste heat, or renewable energy sources (like solar thermal or geothermal) and stores it for later use.

Applications:

District Heating: Varanto is primarily designed to support district heating networks, which provide heat to residential and commercial buildings. By storing heat in the summer and releasing it in the winter, Varanto helps reduce reliance on fossil fuels for heating during colder months.

Renewable Energy Integration: The system can store excess heat generated from renewable sources, reducing energy waste and improving the efficiency of renewable energy systems.

Comparison to Other Thermal Batteries:

Duration: Most thermal batteries store energy for hours or days, while Varanto stores energy for months.

Scale: Varanto is much larger in scale, designed to meet the heating needs of entire cities or regions, whereas smaller thermal batteries are typically used for industrial processes or localized grid support.

Medium: Varanto uses water as its storage medium, while other thermal batteries may use materials like molten salt, graphite, or crushed rock.

Why Varanto is Important
Decarbonizing Heating: Heating is a major source of carbon emissions, especially in colder climates. Varanto provides a way to store renewable or waste heat and use it when needed, reducing the need for fossil fuel-based heating systems.

Energy Efficiency: By capturing and storing excess heat that would otherwise be wasted, Varanto improves the overall efficiency of energy systems.

Grid Stability: Seasonal storage helps balance energy supply and demand over longer periods, complementing shorter-duration thermal batteries and other energy storage technologies.

How Varanto Complements Other Thermal Batteries
Short-Term vs. Long-Term Storage: While thermal batteries like those from Rondo Energy or Antora Energy focus on short-term storage for industrial processes or grid support, Varanto addresses the need for long-term, seasonal storage. Together, these technologies create a more comprehensive energy storage ecosystem.

Integration with Renewables: Both Varanto and smaller thermal batteries can integrate with renewable energy sources, but they serve different roles. Varanto stores energy for months, while smaller thermal batteries provide flexibility on a daily or weekly basis.

District Heating vs. Industrial Use: Varanto is tailored for district heating, while other thermal batteries are often used in industrial settings or for electricity grid support.

Conclusion
Varanto represents a critical piece of the thermal battery puzzle, addressing the challenge of long-duration energy storage for heating applications. While most thermal batteries focus on shorter-term storage, Varanto’s seasonal storage capabilities make it uniquely suited for district heating and large-scale renewable energy integration. Together with other thermal battery technologies, Varanto helps create a more flexible, efficient, and sustainable energy system.

http://www.vantaanenergia.fi/en/varanto%20

[Sparty]

Hot dry rocks can be considered a form of nature’s long-duration energy storage. These rocks, found deep within the Earth’s crust, store vast amounts of heat energy over geological timescales. This heat can be harnessed for human use, particularly through Enhanced Geothermal Systems (EGS), making hot dry rocks a natural and sustainable source of long-duration thermal energy storage.

What Are Hot Dry Rocks?
Hot dry rocks are subsurface rock formations that are heated by the Earth’s internal geothermal energy but lack the water or permeability needed to naturally transfer heat to the surface. These rocks can reach temperatures of 150°C to over 300°C at depths of 3 to 5 kilometers or more, depending on the location.

How Do Hot Dry Rocks Store Energy?
Natural Heat Reservoir:
The Earth’s core continuously generates heat through the decay of radioactive isotopes and residual heat from planetary formation. This heat is conducted slowly through the Earth’s crust, warming rocks over millions of years.

Long-Duration Storage:
Hot dry rocks retain this heat for extremely long periods, effectively acting as a natural thermal battery. The heat is stored until it is extracted or dissipates over geological timescales.

Harnessing Hot Dry Rocks for Energy
To access the heat stored in hot dry rocks, humans use Enhanced Geothermal Systems (EGS). Here’s how it works:

Drilling: Wells are drilled deep into the hot dry rock formations.

Fracturing: The rocks are fractured (using hydraulic or other methods) to create pathways for water to flow through.

Water Injection: Cold water is pumped down one well, where it absorbs heat from the rocks.

Heat Extraction: The heated water is brought to the surface through another well, where the heat can be used for electricity generation, industrial processes, or district heating.

Recycling: The cooled water is reinjected into the system, creating a closed-loop cycle.

Why Hot Dry Rocks Are Like Long-Duration Energy Storage
Vast Energy Capacity:
Hot dry rocks store enormous amounts of heat energy, far exceeding human energy needs. This makes them a virtually inexhaustible energy source.

Long-Term Stability:
The heat in hot dry rocks is replenished by the Earth’s internal processes, ensuring a continuous and stable energy supply over long periods.

Seasonal and Multi-Year Storage:
Unlike human-made thermal batteries, which store energy for hours, days, or months, hot dry rocks can store heat for thousands or even millions of years, making them a true long-duration energy storage system.

Advantages of Hot Dry Rocks as Energy Storage
Renewable and Sustainable:
The heat in hot dry rocks is continuously replenished by the Earth’s internal processes, making it a renewable energy source.

Low Emissions:
Geothermal energy from hot dry rocks produces minimal greenhouse gas emissions compared to fossil fuels.

Baseload Power:
Unlike solar or wind energy, which are intermittent, geothermal energy from hot dry rocks can provide a constant and reliable energy supply.

Global Potential:
Hot dry rocks are found almost everywhere beneath the Earth’s surface, making geothermal energy a widely accessible resource.

Challenges of Using Hot Dry Rocks
High Initial Costs:
Drilling deep wells and creating fractures in hot dry rocks is expensive and technically challenging.

Geological Risks:
Fracturing rocks can sometimes cause seismic activity (small earthquakes), which needs to be carefully managed.

Location-Specific:
While hot dry rocks are widespread, the most accessible and economically viable resources are often located in regions with high geothermal gradients.

Water Usage:
EGS requires significant amounts of water, which can be a limitation in arid regions.

Examples of Hot Dry Rock Projects
Soultz-sous-Forêts (France):
One of the first EGS projects, demonstrating the feasibility of extracting heat from hot dry rocks.

Cooper Basin (Australia):
A high-profile EGS project aiming to tap into some of the hottest and deepest rocks for geothermal energy.

Fenton Hill (USA):
An early experimental EGS site in New Mexico that paved the way for modern geothermal technologies.

Conclusion
Hot dry rocks are indeed nature’s long-duration energy storage, holding vast amounts of heat energy over geological timescales. By harnessing this energy through Enhanced Geothermal Systems (EGS), we can tap into a renewable, sustainable, and virtually limitless energy source. While there are technical and economic challenges to overcome, hot dry rocks have the potential to play a significant role in the global transition to clean energy, complementing other forms of energy storage and renewable energy technologies.

[Sparty]

Read about : Australia "the lucky energy" country could become one of the world's leaders in Hot Rock Energy research and development as a result of Australia's almost unique combination of abundant, relatively shallow, massive, horizontally fractured, richly radiogenic granite lenses covered by thick sedimentary layers acting as thermal insulators.

Australia's very hot, shallow, Hot Rock lenses are, unlike those overseas, horizontally layered and fractured, due to the tectonic shift of Australia into Asia. This horizontal layering and fracturing allows for the establishment of up to 4 times larger engineered heat exchangers than areas with vertical fractures. According to recent article in The Australian the director of the Petroleum & Geothermal Primary Industries & Resources SA Mr Barry Goldstein: "So these heat exchangers are nearly horizontal and that is due to the compressive stress on the rock from Australia bumping into Asia. The high temperatures, the high stress and the direction of the stress is almost unique in the world."

https://www.hotrockenergy.com/austra...-very-hot.html

More: Australia’s unique geological characteristics, particularly its hot, shallow, horizontally layered, and fractured rock formations, make it a global standout for geothermal energy development. These features, driven by the tectonic forces of Australia colliding with Asia, create ideal conditions for engineered geothermal systems (EGS) with significantly larger and more efficient heat exchangers compared to regions with vertical fractures. Here’s a deeper dive into why Australia’s geothermal resources are so special and how they can be harnessed:

Why Australia’s Hot Rock Lenses Are Unique
Horizontal Layering and Fracturing:

Unlike many geothermal resources overseas, which feature vertical fractures, Australia’s hot rock formations are horizontally layered and fractured due to the tectonic compression caused by the continent’s northward drift into Asia.

This horizontal fracturing allows for the creation of larger engineered heat exchangers—up to four times larger than those in vertically fractured systems.

Shallow High-Temperature Resources:

Australia’s geothermal resources are relatively shallow, with high temperatures (up to 250°C or more) found at depths of 3 to 5 kilometers.

This reduces drilling costs and makes the heat more accessible compared to deeper resources in other regions.

Compressive Stress:

The tectonic forces acting on Australia’s crust create a unique stress field that favors horizontal fracturing. This stress field is almost unparalleled globally, making Australia’s geothermal resources particularly valuable for EGS development.

Advantages of Horizontal Heat Exchangers
Larger Surface Area:
Horizontal fractures provide a much larger surface area for heat exchange compared to vertical fractures, significantly improving the efficiency of heat extraction.

Enhanced Fluid Flow:
The horizontal orientation allows for better fluid flow through the fractures, reducing the risk of blockages and improving the longevity of the geothermal system.

Higher Energy Output:
The larger heat exchangers enable more heat to be extracted from the rocks, increasing the overall energy output of the system.

Reduced Costs:
The ability to create larger heat exchangers with fewer wells reduces drilling and operational costs, making geothermal energy more economically viable.

Potential for Geothermal Energy in Australia
Massive Resource Base:
Australia’s geothermal resources are estimated to be vast, with the potential to provide baseload power (24/7 energy) for thousands of years.

Decarbonization:
Geothermal energy can play a key role in Australia’s transition to clean energy, reducing reliance on coal and gas for electricity and industrial heat.

Regional Development:
Many of Australia’s geothermal resources are located in remote and regional areas, providing opportunities for economic development and energy independence in these regions.

Challenges and Opportunities
High Initial Investment:
While Australia’s geothermal resources are promising, the upfront costs for drilling and developing EGS systems remain high. Government support and private investment will be critical to scaling up the industry.

Public Awareness:
Geothermal energy is still underappreciated in Australia compared to solar and wind. Raising awareness of its potential is essential for gaining political and public support.

Technological Innovation:
Advances in drilling technology, fracture stimulation, and heat extraction methods will be key to unlocking the full potential of Australia’s geothermal resources.

Key Projects and Leaders
Cooper Basin (South Australia):

One of Australia’s most promising geothermal regions, with temperatures exceeding 250°C at depths of around 4 kilometers.

Companies like Geodynamics (now part of ReNu Energy) have pioneered EGS development in this area.

Petroleum & Geothermal Primary Industries & Resources SA:

Under the leadership of Barry Goldstein, this organization has been instrumental in promoting and developing South Australia’s geothermal resources.

Other Regions:

Geothermal potential has also been identified in Queensland, New South Wales, and Western Australia, though development in these areas is still in its early stages.

Conclusion
Australia’s hot, shallow, horizontally layered, and fractured rock formations are a unique and highly valuable resource for geothermal energy development. The horizontal fracturing, driven by tectonic forces, allows for the creation of larger and more efficient heat exchangers, making Australia’s geothermal resources some of the most promising in the world. With the right investment, innovation, and policy support, geothermal energy could become a cornerstone of Australia’s clean energy future, providing reliable, baseload power and helping to decarbonize the economy. As Barry Goldstein highlights, Australia’s geothermal resources are almost unique globally, offering a tremendous opportunity to harness nature’s long-duration energy storage for sustainable development.