As the world pivots toward renewable energy to reduce its dependence on fossil fuels and combat climate change, geothermal energy has emerged as a promising alternative. With a large potential for clean, reliable and sustainable energy generation, geothermal energy may play a dominant role in helping transform the energy landscape.

In this article, we explore the technical aspects, challenges and innovations surrounding geothermal energy, using Iceland as a case study to demonstrate the impact this energy source can have on a nation’s energy economy. Finally, we discuss the opportunities for geothermal energy development in the U.S., and consider the future of its role in global renewable energy production.

Geothermal energy: An overview

Geothermal energy refers to the heat generated and stored within the Earth's crust. This energy can be harnessed by tapping into underground reservoirs of hot water and steam, which can then be used to generate electricity or provide direct heat for various applications.

There are two primary methods for harnessing geothermal energy. The first method, direct use, involves using hot water from shallow wells for heating applications, such as space heating, greenhouses and aquaculture. The second method, electricity generation, utilizes high-temperature (above 150° C) geothermal resources to generate electricity. Steam or hot water from deep wells is used to drive turbines, which in turn generate electricity.

While the concept of geothermal energy may be straightforward, realizing its potential at scale in practice requires solving numerous engineering challenges. Sophisticated technologies are required for exploration, drilling, power production and distribution, and more. With an increasing emphasis on renewable energy, these technologies are expected to continue to develop, and help achieve a greener energy landscape.

Figure 1: Simplified schematic of geothermal energy production. Source: VectorMine/Adobe Stock

Technical challenges and innovations in geothermal energy

Despite its potential, geothermal energy faces several technical challenges that limit its contribution to the renewable energy revolution. The first and greatest hurdle is the limited resource availability. Unlike solar energy, which is suitable for a wide range of different geographic locations and climates, high-temperature geothermal resources are primarily found in areas with volcanic activity, which may limit widespread adoption.

Even with resource availability, finding the precise location for drilling can be a major challenge, leading to high costs of exploration and drilling. Identifying and accessing geothermal resources can be both expensive and risky, as drilling deep wells is a complex and uncertain process. Environmental concerns also arise, as geothermal power plants may still release greenhouse gases such as carbon dioxide and methane, although at much lower levels than fossil fuel plants. Additionally, the extraction of geothermal fluids may cause land subsidence or induce seismic activity.

Overcoming these challenges requires innovations in geothermal technology. One such example is with enhanced geothermal systems (EGS), which involves the creation of artificial reservoirs in hot dry rocks by injecting water at high pressure. This technology can expand the potential of geothermal energy to regions without sufficient naturally occurring reservoirs.

Another key category of technologies in need of further innovations are in advanced drilling techniques. Innovations in drilling such as plasma pulse drilling and spallation drilling can reduce costs and increase the efficiency of accessing geothermal resources. To mitigate the accompanying release of greenhouse gases, carbon capture and storage (CSS) can be used by capturing and storing carbon dioxide underground.

While there remain many technical challenges in achieving the full potential of geothermal energy, innovative technologies are expected to help realize this renewable energy source’s impact on the global energy portfolio.

Iceland: A case study in geothermal energy

Iceland serves as an exemplary model for the successful implementation of geothermal energy. Boasting an abundance of geothermal resources due to its unique geological location on the Mid-Atlantic Ridge, Iceland generates over 25% of its electricity from geothermal sources. Moreover, an impressive 90% of Icelandic homes are heated using geothermal energy.

The Hellisheidi Geothermal Power Plant, the world's third-largest geothermal power station, epitomizes Iceland's commitment to clean energy. Located just outside the capital of Reykjavik, the plant has a capacity of 303 MW, providing electricity and hot water to the capital city and surrounding areas.

Several factors have contributed to Iceland's geothermal success. First, the country's favorable geological conditions, as its location on the Mid-Atlantic Ridge, coupled with volcanic activity, provides an abundance of high-temperature geothermal resources. Second, Iceland's government has actively invested in geothermal energy infrastructure and research, fostering a conducive environment for growth. Finally, innovation and expertise have played a significant role, with Icelandic companies and researchers at the forefront of geothermal technology. They focus on drilling techniques, turbine efficiency and environmental impact mitigation.

Figure 2: Geothermal energy production at a plant in Iceland. Source: Tony Craddock/Adobe Stock

Opportunities for geothermal energy in the U.S.

The U.S. has vast untapped geothermal potential, with the largest resources located in many western continental states, as well as Alaska and Hawaii. According to the U.S. Geological Survey, the country has an estimated potential of more than 100 GW of geothermal power, enough to power millions of homes.

Several factors make the U.S. an ideal candidate for geothermal energy development. The country boasts abundant geothermal resources, including high-temperature hydrothermal systems and vast areas suitable for EGS development. Additionally, the U.S. has a well-developed energy infrastructure, which can be leveraged to support the integration of geothermal power into the grid. Lastly, with a strong research and development ecosystem, the U.S. can drive innovation in geothermal technology and reduce costs.

To capitalize on these opportunities, the U.S. can take several steps. Increasing investment in research and development can accelerate technology advancements and drive down costs by funding geothermal research and pilot projects. Developing supportive policies and regulations, such as tax credits and grants, can encourage private investment in geothermal energy projects, while streamlined permitting processes can help reduce project timelines. Finally, fostering international collaboration can help the U.S. learn from the success of countries like Iceland by partnering with them in technology exchange, research collaboration and capacity building.

The future of geothermal energy

As the world continues to transition toward renewable energy sources, geothermal energy presents a compelling opportunity to diversify our energy portfolio and reduce our reliance on fossil fuels. Iceland's experience serves as a powerful example of how a country can harness its geothermal potential to achieve significant clean energy goals.

The U.S., with its abundant geothermal resources and strong research and development capabilities, is well-positioned to become a leader in the global geothermal energy landscape. By addressing technical challenges, investing in innovation and implementing supportive policies, the U.S. can unlock the full potential of geothermal energy and contribute to a sustainable energy future.

Looking ahead, the future of geothermal energy is promising. As technology advances, costs decrease, and global awareness of the importance of clean energy grows, geothermal energy is poised to play an increasingly significant role in the world's energy portfolio. The expansion of EGS and advanced drilling techniques will likely open up new possibilities for harnessing geothermal energy in regions previously considered unsuitable. Furthermore, ongoing research into reducing the environmental impact of geothermal power plants will ensure that this energy source remains an environmentally friendly option.

The future of geothermal energy is bright, with immense potential for growth and innovation. As countries like Iceland and the U.S. continue to tap into this powerful resource, we can expect geothermal energy to play a vital role in the global transition toward a more sustainable and clean energy future.

About the Author

Tyler Gleckler is an accomplished scientist, writer and renewable energy expert with a strong background in chemistry. He holds undergraduate and graduate degrees in chemistry, having studied and worked at prestigious institutions such as the University of Oxford, the University of Edinburgh, the National University of Singapore and the Hebrew University of Jerusalem. With a research focus on material chemistry and applied nanotechnology, Tyler has worked on a diverse set of projects, spanning many subjects and applications.