Feel the heat

With the need for innovative solutions to meet climate change targets, and declining growth in clean energy innovation, comes an opportunity for disruption; for new or underutilised technologies to move to a prominent position on the energy stage.

Geothermal energy

Geothermal energy has long been used as a direct source of heat and for generating electricity, with a global installed electricity capacity of 15 608 MW in 2020. To date, however, geothermal sources provide only a fraction of the world’s energy needs. With increased reliance on variable supplies such as wind and solar, policy disincentives for fossil fuels, and developments in energy storage and distribution, the time could now be right for its wider scale adoption, and many experts see geothermal energy as an essential component in the future energy mix.

Geothermal energy utilises the Earth’s internal heat – heat generated during the formation of the planet and sustained by radioactive decay. Since it can be used without being depleted, it fits the definition of renewable energy. The flow of heat to the Earth’s surface is estimated at approximately 43 - 49 TW, which more than doubles humanity’s current energy consumption, but geothermal energy extraction has, to a large extent, been constrained to regions with active volcanoes or where plate boundaries merge. Here, the Earth’s internal heat is accessible at, or close to, the surface. One of the most active geothermal areas is called the Ring of Fire, which encircles the Pacific Ocean and is home to New Zealand, Indonesia, the Philippines, Japan, the West Coast of the US, and Mexico. All of these regions are represented in Think GeoEnergy’s Top 10 Geothermal countries for 2021; a list which also includes Turkey, Italy, Kenya, and Iceland, all countries known for their volcanic activity.2

However, as evidenced by the Eden Geothermal project in the UK, the geographical reach of geothermal energy utilisation has been broadened by developments in deep-drilling techniques, which allow access to high temperatures in the Earth’s mantle 2 - 3 miles down. At these sorts of depths, hot water or rock can be accessed across much of the planet, meaning that utilisation of geothermal energy is not so geographically constrained. Indeed, research has shown that geothermal energy could provide 20% of the UK’s electricity demand, in addition to heating.

Research has shown that when geothermal energy is developed, it will be capable of providing approximately 20% of the UK’s current electricity demand plus a vast amount of heating.

Patent trends in geothermal energy

Evidence of innovation relating to deep-drilling is supported by patent data, where geothermal energy filings for drilling

Figure 1. Geothermal energy has long been used as a direct source of heat and for generating electricity, with a global installed electricity capacity of 15 608 MW in 2020.

techniques come second only to heat pumps, with over 8000 patents in the last 10 years.

There is also substantial patent activity relating to three types of geothermal power station. Each operates in a different way, but implements the same basic design of drawing hot water and steam from the ground to spin turbines and generate electricity. Traditional dry steam geothermal power stations show the most patent activity, with over 5000 patents filed in the last 10 years, while there are nearly 4000 filings for more complex (and more common) flash steam power stations. Both rely on high temperatures: 150˚C or higher for dry steam and 180˚C or higher for flash. By contrast, more recent binary cycle power stations are able to utilise fluid temperatures as low as 57˚C. To date, filings in this area are lower, at nearly 2000. However, lower temperatures bring greater flexibility, and this, coupled with advances in deep-drilling, has the potential to see geothermal energy utilisation more widely deployed in the future.

Another key area of development for geothermal energy is remote sensing, where nearly 4500 patents were filed in the last 10 years. These are sophisticated devices and techniques, many using AI to advance geothermal exploration. Technical advances have the potential to drive down the cost of exploration and reduce risk to investors.

Heat pumps account for over half of patent filings officially tagged as geothermal energy in the last 10 years. While many of these filings relate to ground source heat pumps which utilise solar energy absorbed at the Earth’s surface rather than geothermal energy in a strict sense, the high patent activity is an indicator of innovation in an area that has potential to reduce reliance on fossil fuels and drive down emissions.

Geographical distribution of patent activity

Geographical distribution of patent activity gives insight into the location of technology centres with specialisms in different aspects of clean energy innovation. According to the EPO/IEA report, centres in Europe, Japan, and the US dominate, accounting for more than three-quarters of patent filings since the turn of the century. South Korea and China are some way behind, but show a sustained increase in recent years.

Japanese, US, and South Korean companies all appear in the top 10 applicants for geothermal patents in the period from 2010 - 2020, with Toshiba heading the list, followed by Haliburton and GE. However, the top 10 companies account for only 6.5% of total filings, indicating a wide spread of applicants in this open and emerging field. Looking at where these applicants are filing patents, China dominates, followed by the US, Japan, South Korea, Australia, Canada, and Germany.

Notably, the geographical distribution of patent activity in geothermal energy does not correlate directly with production. While the US and Japan are both listed in the top 10 producers of geothermal electricity, China is not. The use of geothermal resources in China has a long history, but large scale exploration and development only began more recently. For decades, low-temperature geothermal resources in China were directly utilised, but geothermal energy generation is still in its infancy, which may explain China’s absence from the top 10 geothermal energy producers, despite a high level of R&D activity in the field.

Indonesia and the Philippines also present interesting anomalies. They occupy the number two and three spots in the top 10 geothermal energy producers. Indeed, with measures in place to reduce reliance on coal, Indonesia looks set to move to the number one spot. However, there are very few patent filings in these countries, suggesting that applicants may be neglecting key territories. The finding reflects a challenging patent environment and barriers to licencing and commercialisation of IP assets in both countries. The US Chamber’s International IP Index, which scores countries on the strength of their IP systems, ranks Indonesia 51st out of 55 countries, with a score of 30.42%, and the Philippines 37th , with a score of 41.58%. However, this could change over the 20-year lifetime of a patent, and applicants for geothermal energy technologies would do well to give thought to filing patents in countries where geothermal energy plays a key role in the economy.

Patent activity by research organisations

Another interesting statistic to come out of the EPO/IEA report is that patent filings in the geothermal energy field originating from public research organisations and universities has increased from 2% in the period from 2000 - 2009, to 11% in the period from 2010 - 2019. Although this is not high compared to areas such as carbon capture and bioenergy, an increase in interest by research organisations often precedes increased activity on an industrial scale and should be regarded as a positive sign for geothermal energy.

Summary

At present, geothermal energy is a small but important player on the global energy stage. In those countries where geothermal resources are easily accessible, geothermal solutions present a clean, reliable, and consistent source of heat and electricity. And improvements to geothermal exploration, deep-drilling, and utilisation of lower temperatures have the potential to make geothermal energy more widely accessible.

Most net zero scenarios rely heavily on wind and solar. The variable nature of these renewable energy sources, which are dependent on seasons and the weather, means that they require support from other technologies which are not quite there yet. Advanced batteries, hydrogen, smart grids, and so on could all fill this gap in time. However, innovators, investors, and policy makers would do well to look at the potential for geothermal energy, with its ability to operate consistently at a high availability rate, to provide support for other renewables.

References

1. European Patent Office, and International Energy Agency. ‘Global trends in clean energy technology innovation’, Patents and the energy transition, April 2021. 2. RICHTER, A. ‘ThinkGeoEnergy’s Top 10 Geothermal Countries 2020 – installed power generation capacity (MWe)’, (January 2022). 3. US Chamber of Commerce Global Innovation Policy Center, 2022 International IP Index: Compete for Tomorrow, 10th Edition (2022).

Max Brouwers, Getech, UK, identifies the ways in which the geothermal industry could be utilised more as part of the global goal to reach net zero, highlighting the growing pressure for renewables to replace fossil fuels in the near future.

Geothermal power generation is witnessing rapid growth worldwide, with installed capacity having grown by approximately 50% in the last five years.1 According to the European Geothermal Energy Council (EGEC), with the right policies in place, geothermal could meet half of the EU’s heating and cooling demand by 2030.2 This would have a material environmental benefit, as heating and cooling in buildings and industry accounts for half of the EU’s energy consumption, the largest energy end use sector ahead of both transport and electricity.3

Geothermal energy is one of the most reliable, sustainable, and efficient energy sources available. It is accessible everywhere in the world and, unlike many other sources, it is not affected by the vagaries of the weather – making it the perfect green baseload energy source. Crucially, it can provide domestic energy security, significantly reducing reliance on imported sources of power.

However, despite the fact that Europe rests on a vast amount of geothermal energy that can provide permanent supplies of renewable heating, cooling, and power, it remains underdeveloped and often out of sight for policy makers.

The resources are broadly (and informally) grouped into shallow and deep geothermal, based on the subsurface temperatures and the technologies used for extracting the heat.4 Shallow systems generally require ground source heat pumps to modify the temperature obtained from the geothermal resource for use in domestic or commercial heating and cooling applications. In deep systems, the subsurface is at a high enough temperature to be used directly for heating or electricity generation.

According to recent research published by the UK’s Parliamentary Office of Science and Technology (POST), geothermal technologies currently deliver less than 0.3% of the UK’s annual heat demand, using only a fraction of the estimated available geothermal heat resource.4 Despite there being potential to increase this proportion significantly and contribute to the UK’s net zero targets, deep geothermal is currently not included in the UK’s carbon budget or government strategies.

In addition to space heating and cooling applications, the subsurface can also be used for storing excess heat from other sources, including renewables (such as solar thermal) and industrial processes. Systems that pump heat into the ground for storage can address the mismatch between heat supply and demand, and increase the overall efficiency of renewable heating and cooling systems.

Developing a global market for geothermal energy

The UK’s Climate Change Committee predicts that approximately 20% of UK heat will need to come from low carbon sources by 2050 if the UK is to meet its carbon targets cost effectively.5 Geothermal technologies, from ground source heat pumps to deep geothermal sources, can be connected to heat networks, and have one of the lowest carbon footprints for space and water heating.6 However, the use of geothermal energy for supplying heat networks is only just emerging in the UK.

A recent industry report from The Association for Renewable Energy and Clean Technology (REA) and Arup suggested that, should the government establish a geothermal development incentive, 12 deep geothermal projects could become operational by 2025.7 The report states that these could provide heating to 50 000 homes, create 1300 jobs, and generate more than £100 million of investment in the UK.

Assuming favourable market conditions, including government support, and leveraging the UK’s drilling capabilities in the oil and gas sector (12 - 15 wells/y), the report suggests that 360 sites could be established by 2050, providing £1.5 billion of investment, 15 000 GWh of heat for over 2 million homes, and an annual carbon saving of 3 million t.

Geothermal energy has been shown to offer environmental, economic, and technical advantages in comparison to other renewable and non-renewable heating sources. These include a small land area footprint, applications over a range of scales from individual homes to district heating scale, very low greenhouse gas emissions, and the long-term availability of the resource. Paris, for example, has been using geothermal energy for