Geothermal Energy, Sustainability, and Development


  • PUBLISHED: January 29, 2018

Present and future of geothermal energy according to Riccardo Basosi

Riccardo Basosi is author, with his collaborator Mirko Bravi, of the article “Environmental impact of electricity from selected geothermal Power Plants in Italy“, published in the scientific journal Journal of Cleaner Production in 2014. Since its publication, the article has attracted much attention in the scientific world and in civil society.

Riccardo Basosi, full Professor of Physical Chemistry and Pro-Vice Chancellor for Energy at the University of Siena, and Permanent Italian Representative in the Horizon 2020 Energy Programme.

Full Professor of Physical Chemistry, Pro-Vice Chancellor for Energy at the University of Siena, and Permanent Italian Representative in the Horizon 2020 Energy Programme, Basosi is the author of more than 270 works on physical chemistry and energy issues, focusing on the environmental impact of geothermal energy via Life Cycle Assessment (LCA) analysis.

In this interview, originally published by Geotermia News and now updated, with his agreement, in light of recent developments, he discusses the future of geothermal resources, with a focus on environmental and health sustainability.

In his research, based on ARPAT data on emissions of non-condensable gases from geothermal power plants in the Monte Amiata area from 2002 to 2009, Basosi compares potential impact, in terms of global warming, acidification and human toxicity, of geothermal emissions with those caused by fossil electricity production (natural gas and coal).

Since its publication, the study has been subject to conflicting interpretations (sometimes not exempted from political exploitation), regardless of the scientific intentions of the authors. The main objective of the article is to provide useful information on the environmental impact of geothermal power plants in Monte Amiata, which uses flash technology, so that the information provided could help to identify which technological solutions should be implemented to prevent or reduce this impact, also in view of a potential future increase of electricity production by geothermal sources.

In this interview, Professor Basosi clarifies the results of his study and discuss what could be future updates on this important topic, such as the recent paper “Environmental and social aspects of geothermal energy in Italy”  by Manzella et all.


Professor Basosi, your paper is currently used by some Italian members of the European Parliament to present amendments in the RES directive for more regulations on geothermal. What do you think?

I do not know the details of this political action. The only thing I can say about my paper being used for this purpose is that I do not have any means to control the way it is quoted, even when it is done in a partial or incorrect way. The real problem is that the citation is often misleading, since I am in favour of the development of geothermal energy and I believe that, so far, only an inadequate attention to environmental issues is hindering its development. That is why my research group is still progressing in the analysis and, hopefully, we will be able to submit more LCA papers on this issue in the next future. The abuse of my paper by a political party is not endorsed by me and this should be obvious since, in the paper, we do not show any evidence of risks for human health due to geothermal energy. I am not an epidemiologist and, as I wrote in many articles and interviews (mostly at national level), I do not intend to give my studies any toxicological significance, but only to find a cleaner way to exploit a renewable source.

We are aware of your battles in favour of geothermal research as Italian representative for the Horizon 2020 Programme and for the SET Plan. What is the current situation at the international working tables?

The work of both the H2020 programme and the SET Plan is rightly and strongly influenced by the results of the COP21 Paris agreement in December 2015. Almost the entire international community decided to try and limit the temperature rise resulting from climate change emissions, in particular from carbon dioxide, well below 2 degrees. Moreover, although we can be satisfied by the fact that the agreement has become an international treaty in less than a year (while the Kyoto Protocol took 7.5 years), it should also be remembered that the commitment made by 187 countries still neglect the allocation of 14 billion tonnes of CO2, of which we must get rid quickly if we want to meet the 2-degree target. It is clear to the whole scientific world that this can only be achieved by developing energy efficiency and renewable sources as a replacement for fossil fuels. To this end, all non-fossil energy sources (except for nuclear energy, which presents other problems linked to the excessive durability and disposal of waste), must be developed by using the cleanest technologies possible.

My battle in Brussels in the Energy Committee for Geothermal Energy falls within this framework and there has been a full commitment to take into account the historical tradition of the country and also because I believe that geothermal energy is, among renewable sources, one of those whose potential is currently less exploited and which needs strong technological innovation, for example with the reinjection of the gases that today are subject to emissions, to make it cleaner and therefore usable by the community.

My commitment was focused, with some success, on the financing of low-impact geothermal projects, while other countries supported technological solutions in a perspective that focused more on increasing production.

Scientific statements, if supported by methodological rigor, do not lend to political interpretations. I dare anyone to find in my writings a single sentence in which I say that I am against the geothermal source. This does not prevent me from criticizing environmentally inappropriate technologies if I believe that we can do better.

I think, and I often say this in my lectures, that the only clean energy is the one which is not consumed, i.e. saved. So, the priority should be energy efficiency, both for electricity and heat. All energy sources have some impact. Of course, they have different types of impact and, in a quality scale, the worst are fossil fuels. Among renewables it is possible to define a quality scale too: for example, wind energy sometimes has visual impacts that make it unsuitable for certain contexts; and the same can be said for solar photovoltaic, which I would not put on the dome of the Florence Cathedral. Incidentally, in Florence, there is a significant wind farm between the Cathedral and the Baptistery and that is why those high religious and civil offices are located there: cool in summer and warm in winter. But I would not put in a wind turbine there.

In conclusion, the assessment for which energy source to use must be based on a cost/benefit analysis and must focus on minimizing the impact, which is never zero, on eliminating health risks, and on optimizing the energy process. In the case of geothermal energy, it seems clear to me that we are still far from achieving a fully satisfactory result. For example, the potential offered by multiple uses, even those for heat, does not seem to me to be adequately exploited, with excessive attention being paid to the most valuable production, which is electricity.

In conclusion, I do not believe that there is a definitive solution to the energy problems and I think that every source of energy, especially if renewable, deserves to be used in the historical-geographical context that allows the best development of potential.

In this regard, what are the most sensitive aspects of geothermal energy?

Let’s start by saying that geothermal energy is a valuable resource and, when available, should always be used. It is necessary to implement appropriate technologies that minimize as much as possible the impact on the environment, even to the detriment of economic aspects, if necessary.

When it comes to the use of geothermal energy sources, in fact, both economic and energy sustainability could be improved by linking the direct use of cascading heat to electricity production. In the specific case of geothermal power plants in Monte Amiata, our study has suggested that systems with much lower emissions could be built. However, we are aware of technological limitations due to site-specific resource conditions, which make it difficult to apply alternative and less invasive technologies (e. g. binary cycles or mixed flash-track systems). The complete re-injection of non-condensable gases in contexts like Mount Amiata (geothermal fields with a high percentage of non-condensable gases, elevated pressure, and high temperatures), also considering aspects related to the economic sustainability of such solutions, should be one of the main challenges that geothermal technological research will have to face in the next period.

In the 2014 study, emissions from Monte Amiata geothermal power plants were taken into consideration referring to ARPAT data from 2002 to 2009, while on QualEnergia, in an update of the study in 2015, emissions up to 2010 were also taken into consideration, considering the same 3 impact categories (global warming, acidification and human health). Let us consider global warming, i.e. CO2 equivalent emissions from power plants. In the 2014 study, the emission of greenhouse gases per kWh produced by Monte Amiata power plants is comparable to that of a power plant of equal power fed by fossil fuels. Do you think that these emission values contribute significantly to regional and global greenhouse gas emissions?

It would be better to understand whether CO2 and other greenhouse gas emissions from geothermal power plants have a significant impact on total regional emissions. As a rule, I am not concerned about quantitative levels, since, compared to global emissions, the release of greenhouse gases of geothermal origin is also considered negligible by the IPCC. Our work, however, was preoccupied to say, for the first time, that these were not insignificant quantities as many people thought or as it was proclaimed by interested sources.

Monte Amiata, Italy

As far as the acidification potential is concerned, this seems to be the type of impact that gives more critical results than the other two. However, following the installation in 2014 of the Bagnore 4 power plant, and the partial technological modernization of Bagnore 3, the emission of hydrogen sulphide from the two power plants seems to be decreasing. In fact, the two power plants are connected and constitute the reference technological profile for geothermal power plants in Tuscany. In this regard, do you think that an update of the study, including emissions from the last 2 years, could give different results in terms of acidification?

It would certainly be interesting to work with ARPAT data after2014. Already in the partial update of our study, published in issue 3/2015 of QualEnergia, the hydrogen sulphide emissions detected in 2010 (1,742 tons/year) were lower compared to those of 2007 (2,492 tons/year), but not those of ammonia (4,334 tons/year in 2010 compared to 3,132 tons/year in 2007). The modernizations of Bagnore 3 and the construction of Bagnore 4 have partially modified the emission scenarios of the non-condensable gases, but now it remains to be understood the repercussions of these changes on acidification, global warming, and human toxicity.

Can these conclusions exclude the risk of toxicity to the populations near Monte Amiata associated with the overall emissions of non-condensable gases from geothermal power stations?

The toxicity potential found in our study showed no worrying values. Moreover, a careful monitoring by the ARS (Regional Health Agency) has already been under way for several years and, even though it has detected some critical health problems in the Amiata area compared to other Tuscan areas, it has not yet shown significant correlations with geothermal activity. Nevertheless, it would be interesting to determine how much fine particulates of secondary origin (PM 10 and PM 2.5) originate from the emissions of NH3 and H2S emitted by Amiata’s geothermal power plants; it would be interesting to determine it for geothermal fluids in the Bagnore concession, which have a higher percentage of ammonia than other power plants. The possible increase in acidification of the environment in proximity of the plant remains to be investigated further, but we are working on it.

The 2014 study evaluates emissions from geothermal power plants exclusively related to their operational phase. Do you think that a study that also considers potential impacts on other environmental matrices (e. g. soil) could yield interesting results?

I would like to point out that our study, born of pure scientific curiosity, has so far been self-financed and that any future development would require a commission, preferably public, given the sensitivity of the issues at stake. For the time being, we have considered that the impacts of emissions related to the construction of a power plant (mainly central construction and drilling of wells) can be neglected, if compared to the 25 years of operation of a power plant and considering that plants fuelled with fossil fuel also have plant costs of similar magnitude. However, research aimed at analysing all impacts of electricity generation, using the LCA approach (from cradle to grave), would give results that are more easily comparable with fossil electricity generation. In addition, this would make it possible to compare the impacts generated by electricity production with the different technologies that can be used in geothermal power plants.

Could it be possible to assume similar emission scenarios to those found in your study, in case of utilization of geothermal fluids in other territories with geothermal potential?

Assumptions should be made, but the great variability of fluid characteristics and geological conditions between one geothermal reservoir and the other lead, if not to exclude at least to consider the possibility of similar emission scenarios in other territories quite unlikely. However, the same approach used in our study could also be applied to other geothermal territories and lead to a complete mapping.

In light of the studies carried out by your research group, what technologies do you believe could reduce emissions from geothermal power plants in Tuscany?

Well, surely the installation, where possible, of technologies that reduce the emission of non-condensable gases would have positive effects on the environment. Technological research in the geothermal field should focus on the development of plants with total re-injection of incondensable gases even in complex contexts such as the one in Monte Amiata, even in the presence of high temperatures and pressures. See in this regard the experiences of binary turbines manufacturers like Turboden, Exergy, or ORMAT. Their documents report that their technology can work with up to 15% of non-condensable gas. In addition, it is stated that their plants have power from 250 kW up to 130 MW working with fluids with a temperature between 95°C and 315°C, and a pressure between 1.5 and 25 bar.

The installation of the AMIS systems (Mercury Hydrogen Sulphide Extraction) on all power plants has certainly brought environmental benefits, but what is currently the most advanced, from an environmental point of view, available technological profile? It is necessary, for public control authorities, to be able to deal with this issue, although delicate from the point of view of confidentiality of information by the industrial subjects involved, perhaps making use of the expertise by Tuscan public universities.

What technological framework do you think could be the best for geothermal electricity production?

A technology that considers environmental and social issues, rather than exclusively economic/financial aspects should be developed. In addition to reducing the pressure on the environment, this would also allow to overcome or mitigate the social and political concerns that have hitherto slowed down the development of a particularly valuable resource, both at national level and in the territories where it is located.

I had the opportunity to meet, under their request, some of the representatives of the committees that oppose further development of geothermal energy in the Amiata area. During this confrontation, very civilized, I think I have made it clear that I have always been an advocate of a development of geothermal energy that considers the needs of the population and the environment. However, to promote the diversification of energy supply that favours renewable energy sources, I can only hope that this resource will be more present in the energy package of our country and on a European scale, not only with electricity production, but also with heating production and with heat pumps, which could make the best use of the local resources.


Riccardo Basosi is full Professor of Physical Chemistry and Pro-Vice Chancellor for Energy at the University of Siena. Since 2013, he is also Permanent Italian Representative in the Horizon 2020 Energy Programme and Delegate for the Italian Ministry of Education, University and Research (MIUR) in the SET Plan.


Hit enter to search or ESC to close