ETH Life: The donation from the Siemens Foundation enables ETH Zurich to set up a new chair to head research in deep geothermal energy. Where should focus lie?
Domenico Giardini: Our initial focus will be to research whether or not deep geothermics can be implemented in Switzerland. At present, we can’t say for sure whether we’ll be able to generate five, ten or zero per cent of our electricity and energy with the aid of deep geothermics by 2050. We won’t know the answer until we research the field thoroughly.

The new professorship is incorporated in the geosciences. What questions is it looking to answer?
The professorship should examine the geological environment at depths where heat can be obtained – in other words, observing whether there is any water three to five kilometres beneath the Earth’s surface and identifying the nature of the bedrock. In order to determine where deep geothermics might be deployed, we need to understand the geological landscape as well as define the best extracting methods. We also want to find out if this heat can be used to generate energy. If we want to get the most out of deep geothermics, it is important that we choose the right techniques/procedures.

Is ETH Zurich betting on the right horse in pushing deep geothermic research?
Yes. The Swiss government, cantons, communities and industry are extremely interested in deep geothermics. Industry knows only too well that it won’t get anywhere without research or a better understanding of technology. The Swiss government has set aside another CHF 202 million for energy research for 2013-2016. One of the fields funded is deep geothermics, indicating that the interest in the topic is fundamental and important for society as a whole. I am especially pleased that donors have also taken this message on board and are investing in the development of deep geothermics. The Werner Siemens Foundation also recognised that this field requires research and development, and that this will directly benefit society.

Nonetheless, a lot is still up in the air. Isn’t ETH Zurich running the risk of having to close the deep geothermics file in ten years?
No. In ten years, we probably won’t be producing much electricity with deep geothermics. There will come a phase when the technology will remain in an experimental stage and we’ll have to subsidise electricity from deep geothermics. However, it’s the same story with all new renewable energies. It will take time and new research breakthroughs before deep geothermics can be successful as a technology. So, if the question is whether deep geothermics will still be of interest to ETH Zurich in ten years’ time, the answer is certainly positive - it will be even more interesting than it is today.

In Basel the acceptance of deep geothermal energy suffered a major setback after an earthquake was triggered by deep drilling. How can you convince the general population that exploring and developing geothermics is of value?
People quite rightly have a primal fear of earthquakes. In Basel the methods used that were claimed to entail virtually no risk. Naturally, the public didn’t understand why a supposedly “risk-free” technology caused an earthquake. Going forward we have to proceed with extreme caution because we can’t afford to make any big mistakes, neither in communication nor in technology.

The biggest question seems to be whether there is any potential for deep geothermics in Switzerland. How great is it in your opinion?
Deep geothermics has immense potential as the amount of thermal energy is really quite vast. The depths of our planet are hot, as we know from tunnel constructions like the Gotthard or Neat tunnels. This thermal energy arises through the breakdown of radioactive elements and through the energy that remained trapped inside the Earth after it was formed. If you drill into the depths, the temperature rises twenty to thirty degrees per kilometre.

Is deep geothermics really the inexhaustible energy source it is made out to be?
Yes, it is. If you cool a deep rock volume by using the heat, it will take a long time for it to warm up again. However, the bedrock consists of many cubic kilometres that we can’t use up, even in the distant future. In that sense, deep geothermics is truly inexhaustible.

What happens to the plant if the drilled rock volume has cooled?
The idea is to drill a new rock volume within the premises of the same plant; for example, on the side or further down. The volume is so gigantic that it isn’t a resource problem. The challenge is to install the first successful plant.

The Swiss Federal Office for Energy talks of ten to fifteen per cent of electricity from deep geothermics and a dozen plants by 2050.
Currently, the proportion of deep geothermics in the production of electricity is zero per cent, which is why an increase of one per cent will already be an advantage. However, this wouldn’t solve our energy problems. If we see that the first drillings are heading in the right direction, possibilities will arise to install a sizeable amount by the year 2050, with an output of one gigawatt.

What is your personal opinion on deep geothermics? What proportion of the energy mix will it generate?
The aim is to use it to produce at least five to ten per cent of Switzerland’s electricity by 2050. Otherwise, the technology won’t be worth it. Deep geothermics is still too expensive today. We may not obtain as much energy as we hope in the first phase, but will press to make a breakthrough in the future. ETH Zurich is now doing its utmost to research and promote the technology, devoting two professorships to the field and encouraging industrial collaborations.

Domenico Giardini is a professor of seismology and geodynamics in the Department of Earth Sciences at ETH Zurich, and the Executive Board’s delegate for deep geothermics. From 1997 to the end of 2011, he was the director of the Swiss Seismological Service (SED).