Stainless Steel Propels the Future of Geothermal Energy

With geothermal power generation capacity expected to double by 2040, stainless steel emerges as the key to overcoming its greatest challenges

In the global race toward a cleaner and more secure energy future, geothermal energy is quietly gaining momentum. While solar panels and wind turbines often steal the spotlight, geothermal energy—derived from the Earth’s internal heat—is increasingly recognized as a reliable, low-emission, and scalable solution. Thanks to innovations in drilling technologies, shifting geopolitical priorities, and smarter material choices such as stainless steel, geothermal energy is no longer a niche market but a cornerstone of the green transition.

With years of experience and R&D expertise in stainless steel, we are now focused on exploring how advanced materials can support emerging technologies. Geothermal energy stands out as one of the most promising fields today.

The Untapped Potential of Geothermal Energy
Geothermal energy harnesses the natural heat stored beneath the Earth's surface. This thermal energy can be used to generate electricity or provide direct heating for homes, buildings, and industrial processes.

There are three main types of geothermal power plants:

• Dry steam plants, which directly use underground steam to drive turbines.

• Flash steam plants, which extract high-pressure hot water that rapidly vaporizes into steam as pressure drops.

• Binary cycle plants, which use geothermal heat to vaporize a secondary fluid with a lower boiling point, which then drives the turbine.

Binary cycle plants are particularly exciting because they can operate at lower temperatures, making geothermal energy feasible in more regions.

According to the International Energy Agency (IEA), global geothermal power generation capacity is projected to grow rapidly from the current 16 GW. Under current policies, geothermal generation is expected to exceed 22 GW by 2030 and reach over 40 GW by 2040. This significant leap is driven by both technological innovation and the urgent need to decarbonize energy systems.

Geothermal Cumulative Investment, 2025–2050:

What Is Driving the Momentum of Geothermal Energy?
Several recent developments are accelerating the rise of geothermal energy.

Innovations in drilling technology from the oil and gas industry are reducing the cost of new geothermal wells, while emerging technologies like plasma drilling promise to revolutionize the sector. Additionally, enhanced geothermal systems (EGS) can create artificial reservoirs in hot dry rock, unlocking geothermal potential in areas previously considered unsuitable.

One of the strongest drivers of geothermal growth is the increasing support from governments and international institutions worldwide. Policymakers are recognizing geothermal energy as a strategic asset for transitioning to clean, secure, and resilient energy systems.

In the European Union, the Net-Zero Industry Act has identified geothermal energy as a key technology for achieving green transition goals. The act aims to streamline approval processes, reduce administrative burdens, and direct funding to clean energy infrastructure, including geothermal projects.

The governments of France, Germany, and the Netherlands plan to launch over 200 geothermal heating plants by 2030. Furthermore, numerous projects are being planned or initiated across Europe.

In Europe, brine temperatures for heat transfer generally do not exceed 100°C, and most geothermal plants are used for district heating. However, 2023 marked the second consecutive record year for geothermal heat pump sales, with an 11.7% increase compared to 2022. Notably, even temperatures as low as 80°C can be used for power generation via binary cycles, also known as Organic Rankine Cycles (ORC).

In the United States, support for geothermal energy is gaining bipartisan recognition. The Congressional Research Service notes that enhanced geothermal systems (EGS) have the potential to meet up to 12% of U.S. electricity demand by 2050. The U.S. Department of Energy has also launched an $84 million initiative to fund EGS pilot demonstration projects as part of the Bipartisan Infrastructure Law. These projects aim to showcase EGS applications across various geological settings and advance geothermal energy as a reliable, zero-carbon power source.

The geopolitical landscape, particularly the war in Ukraine and Europe’s energy crisis, has prompted European nations to turn to geothermal energy as a buffer against volatility in global fuel markets. Unlike oil and gas, which are susceptible to geopolitical tensions and price shocks, geothermal energy is inherently localized. Once a geothermal plant is built, it can provide stable, low-cost power for decades, unaffected by international market fluctuations.

The Role of Geothermal Energy in the Green Transition
Unlike solar and wind power, geothermal energy does not depend on weather conditions. In fact, geothermal plants boast a capacity utilization rate of over 75%, compared to less than 30% for wind and under 15% for solar. This makes geothermal energy particularly valuable as a baseload power source—providing stable, round-the-clock electricity to meet constant demand.

In terms of environmental impact, geothermal power plants emit far fewer greenhouse gases than fossil fuel-based plants. According to calculations by the National Renewable Energy Laboratory (NREL), the median lifecycle emissions of geothermal power are comparable to those of other renewables and significantly lower than fossil fuels:

• Coal: 1,001 gCO₂e/kWh

• Natural gas: 486 gCO₂e/kWh

• Solar PV: 43 gCO₂e/kWh

• Geothermal: 37 gCO₂e/kWh

• Wind: 13 gCO₂e/kWh

Beyond environmental benefits, geothermal energy enhances energy security. As a localized source that does not rely on imported fuels, it reduces exposure to global energy market volatility and geopolitical risks. Once operational, a geothermal plant can generate electricity for decades with minimal maintenance, a smaller footprint compared to other energy facilities, and long-term cost stability.

Additionally, certain geothermal fields, such as the Salton Sea and the Upper Rhine Rift, can contribute to energy storage. The highly concentrated lithium in geothermal brines from these areas can be extracted for battery production.

The Advantages of Stainless Steel
Geothermal environments are highly aggressive, with extracted fluids often containing high concentrations of chlorides, hydrogen sulfide, and other corrosive elements. Therefore, material selection is critical for safety, cost-effectiveness, and longevity.

Compared to carbon steel, stainless steel not only offers superior corrosion resistance but also reduces the risk of heavy metal ion deposition—a phenomenon known as "heavy metal scaling," which is particularly common in the Rotliegend formation in the Netherlands and northern Germany. This is due to the passive layer on stainless steel surfaces, which prevents electron transfer between the steel and metal ions, thereby inhibiting deposition.

Key applications of stainless steel in geothermal systems include:

• Heat exchangers: In binary cycle plants, they efficiently transfer heat from geothermal brine to a secondary fluid. Stainless steels like duplex 2205 offer excellent corrosion resistance and thermal conductivity.

• Piping and tubing: Used to transport geothermal fluids, stainless steel ensures durability and reduces maintenance costs. Mechanically lined pipe solutions can be a cost-effective option.

• Well casings: Protect deep geothermal wells from collapse and contamination. Stainless steel is essential in high-chloride environments, withstanding intense thermal and mechanical stress.

• Tanks and valves: Used for chemical storage and handling high-pressure, high-temperature fluids. Stainless steel’s durability reduces the risk of leaks and failures. Often, using duplex stainless steel can also reduce tank weight and lower initial costs compared to coated carbon steel.

• Pressure vessels or reactors for lithium extraction: The process of concentrating lithium chloride and converting it to lithium carbonate under high temperatures and pressures requires highly corrosion-resistant alloys such as 2507 or Sanicro 35.

Stainless steel is more than just a material choice—it is a commitment to the future of geothermal energy. Investing in the right materials today ensures that we harness the Earth's energy safely and efficiently for generations to come. The journey toward a sustainable energy future is not only about adopting new technologies but also about making smarter, more resilient choices in the materials we trust to build that future.