Why Does Geothermal Get Missed in Conversations About Renewable Energy?

This week the European Parliament voted to redefine natural gas as a low-carbon fuel and to give nuclear fission reactors new backing. Now it will be up to each of the 27 members to ratify the EU parliament’s green light.

Of course, if there had never been a Russian invasion of Ukraine, this vote would not have taken place and Europe wouldn’t be looking at abandoning its net-zero vision for 2050. With a renewed interest in natural gas and infrastructure to support it, money poured into this investment will lead to prolonged use of the greenhouse gas (GHG) emitting fuel.

Those who dissented from the decision, many of them representatives of the Green Party, pointed to the fact that the same amount of money to be spent on natural gas infrastructure could be put into wind and solar projects, and adapt the grid to optimize the energy these renewable sources produce. Nobody, however, talked about geothermal.

Geothermal Comes in Many Forms and Has Been Around Awhile

Geothermal energy was exploited by the Romans over two thousand years ago. It was used to heat baths and the floors of villas and homes. It is a considerable contributor to the energy requirements of Costa Rica and New Zealand. Europe’s capacity for geothermal remains largely unexploited to this day and yet the source lies right under the EU’s feet.

Geothermal resources are varied including:

• Low geothermal energy can be exploited by inserting pipes and injecting them with water to depths of between 30 and 600 metres. The natural heat below the surface can then be used with heat pumps or passively to heat structures such as greenhouses.
• Mid-level geothermal energy can be tapped at depths between 600 and 2,500 meters producing water temperatures from 30 to 90 Celsius which can then be fed into heating systems in homes and buildings.
• High-energy geothermal can be harvested at depths over 2,500 meters with the water exceeding 100 Celsius (212 Fahrenheit) and hooked up to steam turbines to generate electricity.
• Hydrothermal convection systems associated with volcanic formations where temperatures underground can exceed 240 Celsius and are more than enough to produce significant amounts of clean thermal power.

Although the EU has studied geothermal energy as a resource they have failed to date to put a lot of money into projects. In 2021, the total amount allocated to 12 pilot projects and research amounted to 172 million euros, a small fraction of what the European community spends monthly on imported energy. That number in 2021 was 25.8 billion euros and with the recent rise in fossil fuel energy prices that euro outflow is dramatically increasing.

Why is Europe Perpetuating Transitional Natural Gas?

European geothermal energy opportunities are numerous. Of the 5,000 heating district networks throughout the EU, today only 280 use any geothermal. But the EU studies point to many missed opportunities that today use fossil fuel energy when geothermal in several forms could replace the burning of coal or the importation of natural gas for heating.

And it appears that applying an old technology to geothermal projects could accelerate projects in Europe and across the planet. A June 28th, 2022 article appearing in the British science publication, The Register, describes the gyrotron, a 1964 Institute of Applied Physics invention coming from the old Soviet Union. Gyrotrons were developed for nuclear physics research looking into fusion.

What is a Gyrotron and How Can It Help?

A gyrotron is a device that generates directed high-intensity microwave beams. It works like a laser but at a different frequency range. When focused on rock it can be used like a drill.

Drilling for oil and natural gas today uses mechanical technology. Using conventional drills favoured by today’s fossil fuel industry would be too expensive for the depths needed to get to superheated geothermal sources. A high-intensity microwave beam, therefore, is seen as a way to get to these energy sources by vaporizing the rock rather than grinding through it.

Quaise Energy, a Massachusetts Institute of Technology (MIT) spinoff, is planning to use gyrotrons to dig the deep holes it needs to harvest geothermal heat. These holes will be the deepest humans have drilled on land as well as on sea.

Paul Woskov, an MIT physics professor working with nuclear fusion, has demonstrated the ability to use gyrotrons to vaporize rock. And although gyrotrons have never been used this way over extended periods of time he believes the technology can do the job. He notes that gyrotron properties are well known and that this novel use to blast holes tens of kilometres deep is the answer to getting to super-hot rocks.

His laboratory tests, see the image at the beginning of this article, have demonstrated vaporizing ability of gyrotrons. The holes seen in that picture are merely a beginning. Now he is using gyrotrons to create holes ten times longer. And next year the plan is to vaporize a hole 100 times longer than that, and so on. By 2025 the plan is to put a prototype gyrotron drilling rig in the field.

Matt Houde and Carlos Araque have been working with Professor Woskov and are the founders of Quaise Energy. Houde recently stated, “We believe, if we can drill down to 20 kilometres, we can access these super-hot temperatures in greater than 90 percent of locations across the globe.” He continues describing deep geothermal as “a power resource that can scale anywhere and has the ability to tap into a large workforce in the energy industry to readily repackage their skills for a totally carbon-free energy source.”

Quaise expects to harvest the heat energy from rocks as hot as 500 Celsius. Remaining challenges include the removal of the unvaporized rock in the hole and picking the right casing materials to line it to keep it stable and open.

Houde’s comment about the availability of a workforce already well-versed using drilling rigs and casings is one that I have stated repeatedly in past postings on this blog site. The skills used in the fossil fuel industry are readily transferable to doing work with geothermal development.

The EU’s vote this week to put natural gas into the low-carbon category along with renewables so that it can subsidize new projects and infrastructure to support a polluting source of energy appears to have overlooked a readily available sustainable alternative – geothermal. We know the EU has plenty of candidate sites. And we know that using gyrotrons with a little more testing and materials selection has the means to make that renewable source a replacement for existing natural gas demand, then why is the EU, and for that matter, North America continuing a love affair with a GHG pollutant that is a contributor to atmospheric warming?