Environ. Sci. Technol. 2010, 44, 6557–6562
Impact of Knowledge and Misconceptions on Benefit and Risk Perception of CCS LASSE WALLQUIST,* VIVIANNE H. M. VISSCHERS, AND MICHAEL SIEGRIST ETH Zurich, Institute for Environmental Decisions (IED), Consumer Behavior, Universita¨ststrasse 22, 8092 Zurich, Switzerland
Received February 17, 2010. Revised manuscript received May 27, 2010. Accepted July 20, 2010.
Carbon Dioxide Capture and Storage (CCS) is assumed to be one of the key technologies in the mitigation of climate change. Public acceptance may have a strong impact on the progress of this technology. Benefit perception and risk perception are known to be important determinants of public acceptance of CCS. In this study, the prevalence and effect of cognitive concepts underlying laypeople’s risk perception and benefit perception of CCS were examined in a representative survey (N ) 654) in Switzerland. Results confirm findings from previous qualitative studies and show a quantification of a variety of widespread intuitive concepts that laypeople hold about storage mechanisms as well as about leakage and socioeconomic issues, which all appeared to influence risk perception and benefit perception. The perception of an overpressurized reservoir and concerns about diffuse impacts furthermore amplified risk perception. Appropriate images about storage mechanisms and climate change awareness were increasing the perception of benefits. Knowledge about CO2 seemed to lower both perceived benefits and perceived risks. Implications for risk communication and management are discussed.
1. Introduction Carbon Dioxide Capture and Storage (CCS) is considered one of the key technologies in decreasing CO2 emissions from burning carbonaceous fuels in power plants and therefore also in the mitigation of climate change (1). Implementation of CCS will, however, depend on public acceptance (2). Past research suggests that risk perception and benefit perception are important predicting factors of public acceptance of emerging technologies such as genetic technology and nanotechnology (3, 4). The present study, therefore, examines factors influencing laypeople’s risk and benefit perception of CCS, before looking at people’s acceptance. We were especially interested in how laypeople’s mental concepts of CO2 and their intuitive understanding of chemical and physical processes shape their perception of CCS. A number of quantitative surveys have examined public acceptance and general attitudes toward CCS (5-10). Results of these studies suggest that public awareness of CCS is low and that knowledge about CCS is very limited. Furthermore, some of these survey studies about the predetermining fac* Corresponding author phone: +41 44 632 3207; fax: +41 44 632 10 29; e-mail:
[email protected]. 10.1021/es1005412
2010 American Chemical Society
Published on Web 08/03/2010
tors of public acceptance of CCS were not based on results from qualitative research with laypeople and therefore may have measured perceptions that were primarily relevant to the survey designers rather than to the general public. The surveys also revealed the role of benefit and risk perception as central determinants of public acceptance in the context of CCS (9, 10). Some have questioned the value of additional surveys related to CCS (11). People do not have preferences about issues they are not familiar with but construct these when asked to respond to such survey questions (12). It is a challenge for social science research about CCS to reduce the impact of irrelevant information on people’s responses in opinion studies. De Best-Waldhober et al. (13) did elicit well-informed public opinions by providing information in manageable chunks that participants were used to. This required considerable effort. It remains questionable, therefore, whether the general public will ever be that wellinformed and whether other aspects that are difficult to control, such as trust in involved stakeholders (14, 15), may still outweigh general information when it comes to public acceptance of CCS. By analyzing influences of laypeople’s concepts on the perception of risks and benefits instead of analyzing influences on acceptance, one can obtain more differentiated insights about their specific impacts. Therefore, the aim of the present study was not to predict public acceptance of CCS in the future but to quantify laypeople’s perception of critical aspects of CCS and to examine their impact on perceived benefits and perceived risks. Laypeople may have never heard of CCS, but that does not mean that they do not have any knowledge about the subject. Carbon dioxide, for example, is an integral element of CCS. Laypeople certainly have specific knowledge or misconceptions about CO2. The relationship between volume and pressure is a concept that children know from the day they blow up their first inflatable rubber balloon, and most people have an idea about the subsurface. When confronted with the basic idea of storing large amounts of CO2 deep underground, a layperson constructs his cognitive model of CCS on the basis of his existing knowledge and possible misbeliefs. People’s misconceptions and lack of knowledge may therefore influence risk and benefit perception of CCS. Several qualitative studies in Europe and in the U.S. have found aspects in laypeople’s concepts of CCS that might influence risk and benefit perception of CCS. A focus group study in the UK examined public perception of geological and ocean storage of CO2 (16). After providing information on the subject, the researchers discussed the storage of CO2 with the participants on quite a general level. Results showed that respondents raised concerns over the integrity of the storage reservoirs and the security of the stored CO2 and mentioned analogues between nuclear waste and the storage of CO2. A study by Palmgren et al. (17) examined laypeople’s mental models related to CO2 storage in geological formations and the deep ocean. Study participants were afraid of environmental harm from sudden CO2 leaks. They were also concerned about CCS being an end-of-pipe solution that delays necessary lifestyle changes and crowds out investment in renewable energy technologies. Similar concerns have been reported from other focus group studies and from a faceto-face survey in the UK (18). Participants were opposed to seeing CCS as a “single fix-it” solution. They were worried about accidents and leakage and called for a reduction of these risks, which were perceived as having negative impacts on environmental and human health. The concept about a large bubble of CO2 that could burst and result in catastrophic VOL. 44, NO. 17, 2010 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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consequences was described. Such a cognitive model of geological storage was also discussed in a recent Swiss study (19). The authors examined lay concepts of CCS in face-toface interviews and observed misunderstandings related to the physical-chemical properties of CO2 and to the perception of an overpressurized reservoir. Socioeconomic concerns about CCS’s lack of sustainability and the risk of a rebound effect were also reported. All of these studies examining people’s concepts used small samples. The prevalence of CCS-specific concepts that may influence risk and benefit perception is therefore unknown. The present study builds on Wallquist et al.’s (19) qualitative research and examines the frequencies of such lay concepts in the general population. In addition, we investigated the impacts of the concepts on risk and benefit perception. This may help to identify critical aspects in nonexperts’ perception of CCS at an early stage of the technology. Knowing about the prevalence and the effect of such critical lay concepts may help communicators inform the public in a more targeted way.
2. Method 2.1. Participants. A mail survey was conducted in the summer of 2009 in the German-speaking part of Switzerland. Households were randomly selected from the Swiss telephone directory. After two reminders and deleting respondents who missed more than 20% of the questions, we used a sample of 654 participants (response rate of 33%). Thirty-seven percent (n ) 239) of the respondents were female. Two persons did not report their gender. Ages ranged from 15 to 94 years. The mean age was 55 years (SD ) 16). Compared to the Swiss population, our sample had a higher education level, included more males (49% of the Swiss adult population is male), and was older (i.e., the Swiss adult population is 48 years on average (20)). 2.2. Questionnaire. Most people are not familiar with CCS. In the beginning of the questionnaire, we provided, therefore, general information about CCS. Based on this information, respondents should have had a basic understanding of what CCS is about. This short text was carefully worded, reviewed by several experts, and aimed at briefing respondents in lay language about the principal aim of CCS technologies (for translated information text, see SI-1). Five items measured the perception of risks associated with CCS (e.g., “Science is underestimating the risks associated with CCS.”). Three statements assessed respondents’ socioeconomic concerns (e.g., “CCS is only fighting the symptoms of climate change, but not the underlying disease.”). Three items measured the perceived risk of slow and steady leakage, explosive leakage, and induced seismicity (e.g., “CCS is increasing the risk of earthquakes.”). Four items measured perceived benefits associated with CCS (e.g., “How high do you rate the benefit from CCS for future generations?”). All these items were measured on six-point scales (i.e., 1 ) totally disagree/very small and 6 ) totally agree/ very high). In the following section, we formulated 19 statements on technical concepts and beliefs (see Figure 1) about properties of CO2, the subsurface, and climate change. Participants were given the choice to agree or disagree with the statements or to indicate that they did not know the answer. The development of most of these items was based on recent qualitative research. The formulations were based on actual statements that respondents had given in the qualitative interviews. Thereby, we kept the wording in nontechnical lay language. Demographics were collected at the end of the questionnaire.
3. Results Thirty-six percent (n ) 236) of the respondents claimed that they had heard about CCS before. This value was higher 6558
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than expected with respect to previous research in other countries (5, 13, 21). In a Eurobarometer study in the EU, an average of 24% of respondents had heard about CCS (results ranged from Italy with 9% awareness to The Netherlands with 45%). A reason for our high awareness result could be that the Swiss media repeatedly reported on CCS in 2008 (22). 3.1. Factors of Measured Concepts. We grouped the measured concepts according to their content into seven different factors: pressurization, socioeconomics, leakage, storage mechanisms, CO2 knowledge, diffuse impact, and climate change awareness. For all items, we standardized the scores by transforming them into z-scores in order to include items that were measured on different scales with respect to the same factor. Items were reversed, when necessary, so that higher scores always indicated stronger agreement or more concern about the underlying concepts. In the following, we present descriptive results and show how we organized the items based on their content into the seven factors. 3.1.1. Pressurization. Laypeople can be expected to be familiar with the concept of pressure and how one can increase or decrease it. When confronted with the idea of storing CO2 underground, respondents accessed their general knowledge to build up their own concept of geological storage. For example, some people seemed convinced that there is no geostatic pressure gradient or, if there is one, that it is not sufficient to keep CO2 in a liquid state (items 1 and 2 in Figure 1). The result for item 3 indicates that half of the respondents thought that the injection of CO2 leads to a persistent pressure change underground. The ultimate reduction of the perceived energy potential could only be reached through the release of the CO2. In fact, in most storage projects (e.g., Sleipner in Norway), the pressure of the reservoir is only temporarily increased by the injection, until subsurface fluid displacement and trapping mechanisms restore the original reservoir pressure. On six-point scales, we additionally measured two potentially perceived consequences of an overpressurized reservoir: induced seismicity (“Storage of CO2 in the subsurface is increasing the risk of earthquakes in the proximity.” M ) 3.20, SD ) 1.40) and sudden explosive leakage (“Storage of CO2 in the subsurface is increasing the risk of an explosive discharge of CO2.” M ) 3.45, SD ) 1.44). These items show that people perceive a moderate risk due to induced seismicity and explosive leakage. The factor Pressurization (Guttman’s λ ) 0.59, N ) 5) includes the discussed items and represents the perceived level of pressurization (natural geostatic pressure and pressurization due to injection-increased reservoir pressure) and potentially interrelated effects (e.g., induced seismicity). [Guttman’s λ is an internal consistency measure of reliability. The highest value for λ is a better lower bound estimation of reliability than λ3 (i.e., Cronbach’s alpha) (23).] 3.1.2. Leakage. We were interested in examining whether respondents are able to distinguish between the severities of different leakage rates. Results for items 5 and 6 show that all leakage was perceived as bad, no matter how much or over what time period CO2 is leaking. For example, 65% percent of the respondents explicitly stated that it would not play a role how fast CO2 is leaking, that it is bad for the environment at any rate. These results suggest a rate-impact insensitivity. Respondents also rated slow and steady leakage as somewhat risky (“There is the risk that CO2 escapes slowly and steadily,” M ) 4.13, SD ) 1.32). Thirty-seven percent of respondents thought leaking CO2 could poison groundwater (item 7). The statement about CO2 being a gas and its subsequent rise to the surface sooner or later (item 4) could be interpreted as a consequence of the prevalent miscon-
FIGURE 1. Percentage of respondents (N ) 654) who did not agree, who did not know, or who agreed with each technical mental concept and belief about CCS. ception about the state of aggregates, because, in fact the CO2 is stored as a supercritical fluid. This underlines the importance of understanding the concept of different states of aggregation to make an informed decision. An expert might also state that supercritical CO2 indeed experiences a buoyant force underground and that diffusion would eventually lead to an escape of some of the gas. Here we have to consider the different time horizons of expert and laypeople views on the issue. Laypeople seem to think of extensive leakage in the very short-term (e.g., 10 years), whereas experts think of marginal amounts on a time scale of thousands of years (cf. ref 24). The factor Leakage (Guttman’s λ ) 0.60, N ) 5) represents the level of concern from leakage, measured with five items. Four of them deal with direct leakage into the atmosphere and one with leakage from the reservoir into aquifers containing drinking water. 3.1.3. Storage Mechanisms. The majority of the general population is not familiar with reservoir engineering and therefore has no knowledge about reservoirs and the mechanisms of geological storage. Nevertheless, our respondents
had an idea about the subsurface. The picture of a balloon that is blown up by CO2 was for most respondents a reasonable representation of CO2 storage (item 9). In contrast, fewer respondents believed that CO2 could be ‘soaked up’ (item 8) or would mineralize with the surrounding rock (item 10). Thus, most respondents seemed to imagine the reservoir as a big cavern filled with pure CO2 rather than as an area of porous rock with small pore spaces containing CO2 and water. The factor Storage Mechanisms (Guttman’s λ ) 0.38, N ) 3) represents the pictures of a balloon, a sponge, and the jointing of CO2 and the rock as illustrations of storage mechanisms. The scale of this factor can be described as a continuum from the perception of big cavities with low jointing of CO2 and rock toward the perception of small pore spaces with high jointing of CO2 and rock. 3.1.4. CO2 Knowledge. The term CO2 is omnipresent these days. Everyone, either through education or the media, has an idea of what CO2 is or what it does. We assumed that people had a certain level of knowledge about carbon dioxide, although they were not familiar with the technology. Item 14, the control item about the origin of CO2, confirmed this. VOL. 44, NO. 17, 2010 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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FIGURE 2. Mean level of agreement and standard error for the socioeconomic concepts and beliefs about CCS. CO2 reminded a considerable part of the sample of a smelly gas (item 11), probably from car exhaust or industry. McCaffry and Buhr (25) reported the lay concept that gas is generally perceived as odorless. However, in the particular case of CO2, the negative connotation of the greenhouse gas seems to have left its marks. Respondents were undecided as to whether CO2 is heavier than air (item 13). A layperson might experience a contradiction when hearing that CO2 is heavier than air on one hand, but on the other hand that CO2 is evenly distributed throughout the atmosphere. The efficiency of atmospheric mixing might thus be underestimated by laypeople. The factor CO2 Knowledge (Guttman’s λ ) 0.54, N ) 4) includes the four questions on the physical and chemical properties of CO2 (items 11-14 in Figure 1). For the calculation of this factor, we recoded correct answers as 1 and wrong and “don’t know” answers as 0, in order to increase the reliability of the scale. 3.1.5. Diffuse Impact. Previous research found that some laypeople perceive diffuse environmental impacts of geological storage of CO2 (18, 19). Our sample showed, as well, that a considerable number of people perceive a general negative impact of CCS on the underground (item 15). Fortyfive percent were convinced that small organisms in the underground could be poisoned and 33%, that the organisms’ genetic structure could be changed (items 16 and 17). The factor Diffuse Impact (Guttman’s λ ) 0.64, N ) 3) includes the three presented questions (items 15-17) and measured the perception of a diffuse impact of stored CO2 on nature. 3.1.6. Climate Change Awareness. The context of climate change is where most people are confronted with the term CO2. Sixty-eight percent of the participants agreed that climate change is virtually certain, and 63% stated that CO2 is the primary cause of this climate change. These numbers are in line with previous studies (e.g. ref 26). The factor Climate Change Awareness (Guttman’s λ ) 0.41, N ) 2) includes items 18 and 19 (Figure 1). For the calculation of this factor, we recoded correct answers as 1 and wrong and “don’t know” answers as 0, in order to increase the reliability of the scale. 3.1.7. Socioeconomic Concerns. Regarding the socioeconomic concerns, it is not possible to clearly assess whether they are right or wrong since, in contrast to most technical concepts, they are value-based opinions. Figure 2 gives an overview of the mean scores of the investigated socioeconomic concepts. Respondents agreed quite strongly about CCS being an unsustainable end-of-pipe solution, which will only be a temporary way out. They likewise perceived a rebound effect as a threat coming from the implementation of CCS (items 1 and 2 in Figure 2). This is in line with previous research (16-18). On the other hand, participants were not overly skeptical about the crowding out of the development of renewable energy technologies by CCS (item 3 in Figure 2). The factor Socioeconomics (Guttman’s λ ) 0.74, N ) 3) contains three items that measure value-based concerns 6560
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TABLE 1. Factors and Their Coefficients of Risk Perception in the Regression Modeld B
SE B
β
constant 0 0.027 socioeconomics 0.511 0.038 0.414c leakage 0.374 0.056 0.230c pressurization 0.315 0.052 0.188c diffuse impact 0.124 0.043 0.094b storage mechanisms -0.131 0.045 -0.086b climate change awareness -0.105 0.036 -0.084b CO2 knowledge -0.116 0.046 -0.073a a
p < 0.05.
b
p < 0.01. c p < 0.001.
d
t 0 13.606 6.62 6.071 2.849 -2.925 -2.957 -2.521
R2 ) 0.52.
about CCS (items 1-3 in Figure 2). More agreement with these three concepts pointed out that CCS would not be perceived as part of an ultimate solution for climate change and that it could retard sustainability efforts. 3.2. Explaining Risk Perception and Benefit Perception. By means of regression analyses, we investigated the impact of the described technical and socioeconomic concepts on risk perception and benefit perception. We formed a risk perception factor by calculating a mean sum score of the five risk perception items (Guttman’s λ ) 0.75), and a benefit perception factor score, using the four benefit items (Guttman’s λ ) 0.92). These two factors showed a negative correlation, r ) -0.49, p < 0.01. 3.2.1. Predictors of Risk Perception. We first analyzed a multiple-regression model with risk perception as the dependent variable, including the seven previously described factors. This model explained 52% of the variance of risk perception (F(7, 646) ) 100.08, p < 0.001, see Table 1). All factors had a significant impact. The dominant predictor that increased risk perception was socioeconomic concerns. Thus, to people’s risk perception, the perceived unsustainable character of CCS was of great importance. Concerns about leakage and the perception of pressurization in the reservoir were also strong positive predictors. The awareness of any kind of pressure due to natural processes or injection of CO2 seemed to increase risk perception. The diffuse impact factor had a moderate positive influence on risk perception. Knowledge about CO2 and the awareness of climate change, on the contrary, mitigated risk perception. Also, the storage mechanisms factor decreased risk perception. Thus, the perception of a jointing between CO2 and the rock and the picture of a porous storage space decreased risk perception. 3.2.2. Predictors of Benefit Perception. We used the same factors in a multiple-regression model in order to explain benefit perception as a dependent factor. This model accounted for 33% of the explained variance (F(7, 646) ) 45.09, p < 0.001, see Table 2). Socioeconomic concerns were the most important predictor of a decrease in people’s benefit perception. This illustrates how intuitively convincing arguments about CCS’s lack of sustainability reduce laypeople’s perceived benefits. Leakage concerns also decreased benefit perception. Thus, some people thought that the actual aim
TABLE 2. Factors and Their Coefficients of Benefit Perception in the Regression Modela,d
constant socioeconomics storage mechanisms leakage climate change awareness CO2 knowledge diffuse impact pressurization a
p < 0.05.
b
B
SE B
β
t
0 -0.520 0.241 -0.249 0.190
0.032 0.044 0.053 0.067 0.042
-0.421c 0.158c -0.153c 0.151c
0 -11.701 4.548 -3.726 4.506
-0.145 -0.031 0.013
0.055 0.051 0.061
-0.091b -0.024 0.008
-2.66 -0.608 0.214
p < 0.01. c p < 0.001.
d
R2 ) 0.33.
of CCS, which is the isolation of CO2 from the atmosphere, would be missed, because so much CO2 would leak out of the reservoir. Climate change awareness and the perception of effective storage mechanisms, such as the picture of a sponge with small pore spaces that store the CO2, allowed for a significant increase in benefit perception. Perceived pressurization and respondents’ concerns about diffuse impacts had no influence. People, thus, seemed to think that, in contrast to slow and steady leakage, pressure changes underground and related effects (e.g., induced seismicity) barely affected the benefits of isolating the CO2 from the atmosphere. Knowledge about CO2 lowered both perceived benefits and perceived risks. This indicates that more knowledge about CO2 might ease down people’s concerns about the risks of CCS but at the same time lead to less confidence in its benefits.
4. Discussion The present research offers new insights into the antecedents of risk and benefit perception of CCS. Some previous qualitative studies have examined laypeople’s perception and concepts of CCS. To the best of our knowledge, no representative surveys have however been conducted that give detailed insights on the prevalence and effect of laypeople’s knowledge about CO2 or on physical, chemical, and geological concepts that influence perception of CCS. By means of a representative mail survey, we revealed the prevalence of critical concepts on CCS among Swiss laypeople that might promote opposition to or support for this set of technologies. We additionally investigated the influence of the concepts on risk and benefit perception of CCS. In the following section, we will discuss the implications of our findings for risk communication with regard to CCS, the role of images, and people’s knowledge of CCS, and we will have a critical look at our study, thereby making suggestions for further research. Socioeconomic concerns about CCS’s unsustainable nature were frequent and most influential on perceived benefits and risks. This finding seems to confirm findings of previous research about the public’s perception of CCS (16-18). Although some of the other factors appeared to make considerable contributions to people’s perceptions in our study, they were always much smaller than the socioeconomical concerns. This finding may indicate that nontechnical factors, such as socioeconomical concerns, are also more important in risk perception and benefit perception of CCS than knowledge and correct beliefs about the technical details of a hazard, as was found for other environmental risks (e.g. refs 27 and 28). Our findings may imply that the large impact of socioeconomical concerns on people’s perceptions underlines the importance of an open societal dialogue on these valuebased worries and on CCS’s function as a potential bridging
technology for electricity generation. Public awareness about CCS’s emission mitigation potential and its role in the energy generation portfolio need to be raised by CCS communicators so that the public can make informed decisions. In addition, people’s nontechnical concerns should be considered in communication initiatives. Communicators should however not neglect the technical factors affecting people’s perceptions of CCS, as most of them still appeared influential on risk and benefit perception. Moreover, knowledge of technical aspects can affect people’s confidence in the feasibility of a technology (29). Our results confirmed that the vast majority of the general population does not have sufficient knowledge to correctly answer technical questions (5). But many people had an intuitive conception of CCS’s functioning after being told about the idea in the information section at the beginning of the questionnaire. Thus, what we measured in this survey was not only the prevalence of knowledge about CCS but also the prevalence of intuitive lay concepts about this set of technologies among the general population. Our results appear to suggest that many people lack the basic physical and chemical understanding about CO2 and the natural conditions in the subsurface. Though most respondents perceived carbon dioxide as a principal cause of climate change, knowledge about the properties of CO2 was very limited, resulting in prevalent misconceptions about CO2 and reservoirs (e.g., about the state of aggregates or the density of CO2 underground). Discussing the high density and the liquid state of CO2 in the reservoir might decrease risk perception of leakage. But ideas about artificial pressurization of the subsurface and cognitive images about the natural geostatic gradient appeared to intuitively amplify risk perception among our respondents. Therefore, communicators should be careful when mentioning that the large injection pressure causes liquefaction of CO2. They need to provide very directed information to rectify incorrect knowledge and to supply missing knowledge, in order to avoid the creation of new misconceptions and misperceptions. Intuitive misconceptions about storage mechanisms appeared to increase risk perception and to decrease benefit perception. We therefore recommend conveying more appropriate mental images that explain the effectiveness of CO2 storage (e.g., the sponge picture) while depicting the structure of the reservoir and the trapping mechanisms. Such illustrations might be helpful in replacing the prevalent intuitive misconception of a pure CO2 bubble underground. Leakage seemed, for our sample, not only to be a risk issue but also a question of benefit reduction. This may also relate to some laypeople’s inability to handle time periods and rates in the context of emitting CO2 into the atmosphere (30). Consequently, laypeople may often show a rate-specific insensitivity and perceive any leakage as bad, no matter how small it may be. The perceptions of impacts on the environment underground were indeed quite common among our sample. However, they do appear to be insignificant to the perception of benefits and not pivotal to the perception of risks. Communications covering these topics are therefore unlikely to change perceptions of CCS. The explanatory power of the risk perception model was substantial, and that of the benefit perception model appeared agreeable, especially considering the rather low internal reliabilities of some of the presented factors, thus indicating the predictors’ multidimensionality. Nevertheless, a few limitations of our research need to be discussed. First, the socio-demographic characteristics of our sample indicated that the sample was not fully representative of the Swiss adult general population. Moreover, as this study was conducted in Switzerland, one should be careful when generalizing our results to other countries. We believe that they can be used as an indication of the public’s perception VOL. 44, NO. 17, 2010 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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of CCS in countries or societies in which CCS is still in a very early developmental stage. Additionally, we do not presume to have fully explained risk and benefit perception in this study. As the explained variances of the two regression models indicated, probably not all factors that explain risk and benefit perception were included in our analyses. An example is the role of trust, which is known to be an important determinant of risk and benefit perception (3), but was not within the scope of this study. Another issue is the stability of the concepts. De Best-Waldhober et al. (13) concluded that traditional surveys on public perception of CCS measure “pseudo-opinions”; opinions that are created on the spot and are thus easily affected by contextual factors and unstable. Therefore, we recommend that researchers and operating companies continue to explore the role of the discussed concepts within experimental studies. They should help to clarify the role and stability of the central concepts of risk and benefit perception and eventually of public acceptance. Thereby, they may also investigate other important determinants of risk and benefit perception. Lack of knowledge seems in some cases to be responsible for decreased, and in others, for increased risk or benefit perception. Thus, simply providing information on the functioning of CCS technologies may not be the magic bullet in communicators’ struggle for informed decisions, as the provision of some knowledge may cause new misconceptions. We believe that experts from engineering and communication need to work closely together in further clarifying the role of the discussed lay concepts and in informing the public about the technology. Due to the public’s limited attention span, such CCS communication should focus on information and images that quickly help nonexperts improve their understanding and avoid information and images that might only increase risk perception without resulting in a better understanding of CCS. The quantitative insights from this study contribute to the development of such risk management and communication tools for CCS.
Acknowledgments The authors would like to thank the “Carbon Management in Power Generation” (CARMA) initiative, which is funded by CCEM and CCES of the ETH Domain, for supporting this work.
Supporting Information Available Information section in the questionnaire, translated from German (SI-1). This material is available free of charge via the Internet at http://pubs.acs.org.
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