The respondents were asked to self-assess their degree of awareness about geothermal energy and to express their opinion and perception about energetic issues, acceptance of geothermal energy for electricity production, and implementation of a pilot project with and without the use of hydraulic stimulation. The selected segment of population has, in general, a medium/high awareness about geothermal energy. Therefore, this exercise indicates that outreach activities should be focused to the remaining segments of the population. In the following subsections, each topic is separately discussed, following the same order used to describe the results in the previous section: 1) issues related with energy production, 2) self-assessed level of knowledge, 3) acceptance of geothermal energy production, 4) impact of hydraulic stimulation, and 5) conditions that should be satisfied to support a pilot geothermal project.
The highlights of these study can be summarized as follows: 1) this exercise provides the first attempt to investigate the geothermal perception of a segment of population in countries belonging to different development categories, 2) in general, high-level educated people have medium/high knowledge of geothermal energy and they may contribute to develop knowledge-sharing mechanisms throughout the whole society, and 3) outreach activities that should be implemented to foster geothermal development have to be addressed to specific segments of population.
In the analyzed countries high-level educated people show higher awareness about geothermal energy than what is indicated by studies that are representative of the whole population. Likewise, in the five countries there is a growing interest in promoting the use of geothermal resources, such that joint studies are useful to share experience and policies.
The main differences are associated with the local economic, social, politic, and energy background: in the literature it is hard to find studies that compare the geothermal energy perception in countries belonging to different development condition as it is done here, with countries from Europe, North, and South America. However, it would be hard to quantitatively compare the answers to this survey if the respondents live in completely different scenarios. Furthermore, the development of a geothermal project is site-specific and can have opposite outcome within the same country, as shown by Yasukawa et al. (2018) in Japan. Therefore, this study focuses on a qualitative analysis of similarities and differences that provides an interesting insight into geothermal perception for a specific segment of the population.
5.1 Description of main issues related with energy production
Energy is seen as a critical factor in providing prosperity for a modern society, but, on the other hand, is a potential source of environmental damage (Wadström et al. 2019). Therefore, there is a close relationship between the production of electricity and environmental impacts, which is determined by sources used for its production. Sources of electrical energy such as fossil fuels, water resources and nuclear fuel are associated to an environmental cost, such as GHG emissions, rigorous procedures for long-term storage of nuclear waste or degradation of aquatic ecosystems. These factors, together with the high dependence of Chile on fossil fuels (O'Ryan et al. 2020), of Colombia and Canada on hydroelectric energy (Gómez and Navarro 2018; CER 2020), of France and Belgium on nuclear energy, make up a critical panorama in environmental aspects and explain the strong concern of respondents about the environmental impacts associated with electricity production. Along the same line, the future development of renewable energies, which are presented as a tool to fight the main environmental aspects associated with electricity production (Owusu and Asumadu-Sarkodie 2016), is the second most important issue identified in the results (Figure 1).
The results obtained can also be interpreted considering the specific context of some of the countries. In Chile, there was a serious electricity crisis that required rationing in 1998 and 1999, and subsequently, there was a significant increase in the cost of power generation in 2007 and 2008, which showed that Chilean installed capacity was not sufficient and that the entire energy system was weak, since it depended mainly on imports. On the other hand, France has the highest percentage (7.5%), among all the countries analyzed, in terms of energy diversification, perhaps because nuclear energy in 2015 represented 78% of electricity generation, the highest share worldwide (IEA 2017). The exploitation of nuclear energy implies the definition of rigorous storage procedures to ensure the long-term management of nuclear waste.
Energy efficiency, supply, and independence can be analyzed together in Belgium. The obtained responses can be affected by the risk of electricity shortage experienced during the winters preceding this survey and explained by technical problems and the temporary closure of some nuclear power plants. This feeling can be exacerbated by the government decision to close all nuclear power plants by 2025 (IEA 2016), affecting the energy matrix of the country, where 49.9% of the energy, in 2017, came from nuclear power (FEBEG 2020). If nuclear power plants are closed by 2025, there will be an impact on the economy: energy imports will be required, and cost will be affected. Therefore, this can explain why respondents are interested in the issue of energy independence.
In addition, it is important to highlight that the cost of energy is one of the main issues raised in these countries and can be related to the need to develop renewable energies, since they should have a lower cost for the users than conventional energy based on fossil fuels.
5.2 Self-assessed level of knowledge
The level of knowledge of geothermal energy is addressed here from a general viewpoint, considering both low and high enthalpy systems. Therefore, the results to this question are described from a general perspective. Although there is a limited overall understanding associated with geothermal energy for general public (Cataldi 1999), Figure 2 shows a medium-high level of knowledge, except for Colombia, where a lower level of knowledge is shown.
In Chile, a study conducted by Vargas (2018) about a community near the Villarrica volcano in the Araucanía region suggests that there is a low level of understanding of the technology involved in geothermal energy production. Moreover, the Chilean National Survey conducted in 2016, indicate that around the 30 % of Chilean population is aware of geothermal energy as a source of electricity (Chilean Department of Energy 2017).
In Canada, Malo et al. (2015) indicated that the population in the Quebec province has a low level of knowledge about surface and deep geothermal energy.
The panorama in Europe is not different to what is happening in Canada, Chile, and Colombia with respect to the level of knowledge: according to the European Geothermal Energy Council, the levels of information and awareness about the different technologies, in particular geothermal energy, can be qualified as low.
Colombia presents the lowest knowledge, which may be related to the level of early geothermal development. It is important to note that the Colombian Association of Geothermal Energy (AGEOCOL) has created different events to disseminate information on geothermal energy, which began in December 2016 with the first national geothermal energy meeting (RENAG) held in Bogotá, just after the implementation of this survey. This could explain the low degree of awareness about geothermal energy recorded.
The results of this survey contrast with the general level of knowledge indicated by the studies mentioned here, except from Colombia. The results strictly apply to a specific group of the population, mainly constituted by persons with post-secondary education.
5.3 Acceptance of geothermal energy production
The level of knowledge of a given technology is not necessarily proportional to its acceptance. Therefore, a question was established to better explore the acceptance of geothermal energy production. This is based on the concept that the social acceptance of geothermal development is not simple (Allansdottir et al. 2019). The results of the question indicate (as presented in section 5.1) that the acceptance of geothermal energy by people who completed the survey is high for all countries, even though the acceptance of a technology is not easy to address from a social perspective. The moderate-high acceptance shown by the respondents may also be associated to the general awareness of global warming and climate change, as well as the importance of a diversified energy matrix, which are topics more and more mentioned in the news and scientific community. It seems that an intuitive or technical knowledge of general or specific aspects of geothermal energy allows people to associate geothermal systems as a technology that opens the door to the energy transition. However, this result is specific for this study and it should not be generalized. In fact, there is limited evidence that more informed individuals show higher acceptance of low carbon technologies, and although some studied indicated a correlation between knowledge and acceptance, others reveal that the levels of support were independent of levels of awareness (Devine-Wright, 2007). Moreover, acceptance varies for each specific project and area of implementation, but a good public information campaign can help communities to correctly understand the different challenges of the project (Colla et al. 2020). In general, the acceptance of new energy technologies has been investigated by different scientific disciplines, but a coherent overview is still missing (von Wirth et al. 2018). It is therefore worth conducting specific case-studies, such the survey described here focused on geothermal energy, to increase the range of available experiences that can be analyzed and compared to foster the development of renewable energies.
5.4 Acceptance of deep geothermal energy to generate electricity, with and without hydraulic stimulation
The question about the acceptance of geothermal energy for electricity generation, indicating a maximum value for Chile with 96.46% and a minimum for Belgium with 79.49%, showed the consistency of the respondents with the answers presented in the previous sections. In contrast, in Chile, the National Survey conducted in 2016 and covering all population segments indicated a lower acceptance (Chilean Department of Energy 2017), confirming that the acceptance varies with the population segment investigated .When evaluating geothermal electricity production with hydraulic stimulation, the results showed a decrease in all countries, with a maximum decrease of 17.97% for France and a minimum of 7.41% for Canada. It is notorious that hydraulic stimulation techniques generate an impact or have a great relevance in the acceptance of the people surveyed, since it can be confused with hydraulic stimulation processes for shale gas extraction. Hydraulic stimulation for geothermal energy has been compared by the public with techniques implemented in hydrocarbon exploitation and associated with fracking (Biello 2013; Sun et al. 2017). Therefore, in several regions of France, there are people who are opposed to hydraulic stimulation for geothermal energy since they point out the risk caused by technology used to facilitate water circulation in the rocks (Meng and Ashby 2014; Chavot et al. 2018). Even though there is a decrease in the acceptance of high enthalpy energy with the implementation of hydraulic stimulation, the acceptance is above 50%, with a minimum of 62.82% in Canada and a maximum of 87.81% for Chile, indicating that for the public surveyed geothermal energy has fair acceptance.
5.5 Conditions that should be satisfied to support a pilot geothermal project
The implementation of a new energy technology, such as geothermal, is limited by community acceptance of its development. To narrow the gap between energy development and acceptance, several conditions must be met to enable communities to support pilot projects. In this case, the public surveyed has selected some aspects that they believe should be satisfied. The aspect that is highlighted as most important is the guarantee of environmental protection, which has been a common factor in the acceptance of geothermal studies (Carr-Cornish and Romanach 2014; Chavot et al. 2018), since the relationship between electrical energy and environmental impacts has resulted, in recent years, in the acceleration of climate change. Therefore, in the implementation of new technologies, a balance must be achieved between electrical production and the environment, and aspects such as the contamination of water resources must be minimized, while appropriate long-term monitoring must be ensured. The second aspect selected by the respondents reflects the need to guarantee the safety of the communities living close to the plant; this aspect can be related to the phenomenon known as "Not in my backyard", where communication plays a relevant role. Involving communities in geothermal projects can improve their position in the acceptance of geothermal energy. Although this survey has been carried out for a specific sector of the society, the answers are consistent with the results of other work focused on social acceptance (Carr-Cornish and Romanach 2014; Malo et al. 2015; Pellizzone et al. 2017). Therefore, environmental aspects, citizen participation, and the integration of social objectives should be a central focus in the implementation of geothermal energy.