When well begun is half done
Peters, Annemijn Maron
DOI:
10.33612/diss.132605604
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Publication date: 2020
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Peters, A. M. (2020). When well begun is half done: How the adoption of sustainable energy technologies can lead to sustainable use of the technologies and other pro-environmental behaviours. University of Groningen. https://doi.org/10.33612/diss.132605604
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5.
General
discussion
General discussion
To combat anthropogenic climate change, changes in human behaviour are needed (see Steg, Perlaviciute, & Van der Werff, 2015), including the adoption of sustainable energy technologies (SET). The adoption of SET is on the rise (IEA, 2018; Eurostat, 2018). SET may have several environmental benefits and may help stabilise the electricity grid, particularly when people not only accept and adopt such
technologies, but also use them in a sustainable way. For example, photovoltaics (PV) will be more sustainable when people match their energy demand to the energy produced by their PV (Geelen, Reinders, & Keyson, 2013; Van der Kam & Van Sark, 2015; Nicolson, Huebner, Shipworth, & Elam, 2017). Moreover, people could match energy demand and supply by installing smart technologies that automatically switch appliances on or off depending on the availability of renewable energy (Kobus, Klaassen, Mugge, & Schoormans, 2015).
Yet, SET do not always lead to sustainable behaviour (Nilsson, Bergstad,
Thuvander, Andersson, Andersson, & Meiling, 2014; Pritoni, Meier, Aragon, Perry, & Peffer, 2015; Abrahamse, & Schwom, 2018). For example, energy demand is often not aligned with PV production: PV produce most during the day, while the demand for energy is particularly high during the morning and evening when PV production is relatively low (Bahaj & James, 2007; Van der Kam & Van Sark, 2015). Similarly, EV’s are typically charged in the early evening when people return home from work, thereby increasing the peak electricity demand (Elaad 2013). To meet these demands,
often peak load power plants are used which emit more CO2 (Cavoukian, Polenetsky
& Wolf, 2010; Ahn, Li, & Peng, 2011; Borenstein, 2012). Also, the stability of the electricity grid may erode when people do not use SET in a sustainable way (Van der Kam & Van Sark, 2015).
While the adoption and sustainable use of SET is important, it is not sufficient
to realise a sustainable energy transition and to limit global warming. People need to engage in a wide range of sustainable behaviours, such as reducing energy use, implementing energy efficiency investment measures, changing travelling behaviour and shifting to a more plant-based diet (Steg et al., 2015; IPCC, 2018). Hence, it is crucial to understand whether and how the adoption of SET not only promotes sustainable use of SET, but also the engagement in other sustainable behaviours.
Studies typically focus on factors that are related to SET adoption (c.f. Rai & Robinson, 2013; Bockarjova & Steg, 2014; Noppers, Keizer, Bolderdijk, & Steg, 2014; Noppers, Keizer, Bockarjova, & Steg, 2015; Korcaj, Hahnel, & Spada, 2015; Palm, 2016; Braito, Flint, Muhar, Penker, & Vogel, 2017) and generally do not consider the engagement in other sustainable behaviours, such as sustainable use of SET, after the adoption of SET. Yet, several studies have examined whether
engagement in one sustainable behaviour affects the likelihood of engaging in subsequent sustainable behaviour (i.e. spillover; Thøgersen & Crompton, 2009; Truelove, Carrico, Weber, Raimi, & Vandenberg, 2014; Nilsson, Bergquist, & Schultz, 2017; Maki, Carrico, Raimi, Truelove, Yueng, & Araujo, 2019). Some studies suggest that engagement in a sustainable behaviour promotes engagement in other
sustainable behaviours (Evans, Maio, Corner, Hodgetts, Ahmed, & Hahn, 2012; Van der Werff, Steg, & Keizer, 2014a, 2014b), while other studies suggest that engagement in sustainable behaviour does not promote (Steinhorst, Klöckner, & Matthies, 2015; Thomas, Poortinga, Sautkina, 2016) or even reduces the likelihood of engaging in subsequent sustainable behaviours (Tiefenbeck, Staake, Roth, & Sachs, 2013). Hence, the question remains which factors affect the likelihood that the adoption of SET results in sustainable SET use as well as engagement in other sustainable behaviours, and how the consistent engagement in sustainable behaviours can be promoted.
In the current PhD dissertation, we first studied whether the motivation to
adopt SET affects the likelihood that the adoption of SET results in sustainable use of SET as well as engagement in a wide range of sustainable behaviours, due to the implication of the motivation to adopt SET for people’s environmental self-identity. Second, we examined whether people’s intention to use SET in a sustainable way before they adopt SET differs from their actual use of SET once SET are installed. Moreover, we examined to what extent possible discrepancies between intended and actual sustainable use may affect environmental self-identity and the motivation to adopt SET. Third, we tested whether emphasizing environmental versus financial benefits of SET affects the engagement in sustainable behaviours, including
sustainable SET use, via motivation to adopt SET, the pro-environmental signalling value of SET and environmental self-identity.
Summary of the main findings
Does the motivation to adopt SET affect consistent engagement in sustainable behaviours?
First, we proposed that the extent to which people use SET in a sustainable way and engage in other sustainable behaviours after the adoption of SET depends on the implication of the adoption of SET for how people perceive themselves. More specifically, we proposed that the adoption of SET may promote sustainable SET use and the engagement in other sustainable behaviours when the adoption of SET strengthens environmental self-identity. We argued that environmental self-identity is more likely to be strengthened when people adopt SET for environmental reasons (i.e. when they have a strong environmental motivation to adopt SET) as in that case people are more likely to realise that adoption of SET benefits the environment, and hence, the adoption is more likely to signal that they are a pro-environmental person. A strengthened environmental self-identity in turn is likely to promote the
engagement in a wide range of sustainable behaviours, including sustainable SET use, because people are motivated to be or appear to be consistent and to align their actions to the way they see themselves (Van der Werff et al., 2013b, 2014a, 2014b; Kashima, Paladino, & Margetts, 2014; Steg, 2016). In contrast, we hypothesized that environmental self-identity is not likely to be strengthened when people adopt SET for other reasons than protecting the environment, such as financial reasons or because they like new technology (i.e. a strong financial and technological motivation to adopt SET, respectively). As a consequence, it is not likely that people would engage in other sustainable behaviours, including sustainable SET use, when people adopt SET for other reasons than protecting the environment.
In Chapter 2 we tested our reasoning by conducting two correlational studies
among adopters of an electric vehicle (EV). More specifically, we tested whether the motivation to adopt an EV affects the likelihood of consistent sustainable behaviour, including the sustainable use of an EV, because of the implications of this motivation to adopt SET for environmental self-identity. We expected that the more someone adopted an EV for environmental reasons (i.e. environmental motivation to adopt EV), the more likely the EV adoption is to signal that one is a pro-environmental
person, thereby strengthening environmental self-identity and promoting consistent sustainable behaviour, including sustainable use of an EV. In contrast, the more someone adopts an EV for other reasons than the environment (in our studies: financial and technological motivation to adopt EV), the less likely this EV adoption is to signal that one is a pro-environmental person, making it less likely that
environmental self-identity will be strengthened and consistent sustainable behaviour will be promoted.
As expected, the results of both studies showed that people are likely to use the
EV in a sustainable way and to engage in other sustainable behaviours when they have a strong environmental motivation to adopt an EV. Importantly, we found that environmental self-identity mediated the relationship between environmental motivation to adopt an EV and the engagement in different sustainable behaviours including sustainable EV use. More specifically, the more people adopted an EV for environmental reasons, the stronger their environmental self-identity and the more likely they are to consistently engage in sustainable behaviour, including sustainable use of the EV. Moreover, financial motivations were not significantly related to sustainable use of the EV and other pro-environmental behaviours in both studies. Also, environmental self-identity did not mediate the relationship between financial motivation to adopt an EV and the different types of sustainable behaviour. Hence, environmental self-identity was not more likely to be strengthened and people were not more likely to engage in different sustainable behaviours when people had stronger financial reasons to adopt an EV.
Results for the technological motivation to adopt an EV were not consistent. In Study 1, environmental self-identity mediated the relationship between technological motivation to adopt an EV and two types of sustainable behaviours, that is, direct and indirect energy saving behaviour. The more people adopted an EV for technological reasons, the stronger their environmental self-identity and the more likely they were to engage in direct and indirect energy saving behaviour. Yet, these relationships were much weaker than the effect of environmental motivation to adopt an EV on direct and indirect energy saving behaviour via environmental self-identity in Study 1, and we did not replicate these findings in Study 2. Hence, overall the results support our reasoning that a stronger environmental motivation to adopt SET is likely to promote sustainable behaviours, including sustainable SET use, by strengthening
one’s environmental self-identity, while stronger non-environmental motivations to adopt SET are not likely to promote consistent sustainable behaviours, because these types of adoption motivation are less or even not likely to strengthen environmental self-identity.
Our studies extend previous studies that typically examined which
psychological factors are related to SET adoption (c.f. Rai & Robinson, 2013;
Bockarjova & Steg, 2014; Noppers, Keizer, Bolderdijk, & Steg, 2014; Noppers, Keizer, Bockarjova, & Steg, 2015; Korcaj, Hahnel, & Spada, 2015; Palm, 2016; Braito, Flint, Muhar, Penker, & Vogel, 2017). We extended this research by testing why and under which conditions the adoption of SET is likely to promote engagement in other sustainable behaviours, including sustainable use of SET, which is critical to
accelerate the sustainable energy transition. As expected, we found that the adoption of SET for environmental reasons may strengthen environmental self-identity and thereby promote consistent engagement in sustainable behaviours, while this is not the case when people adopt SET for other reasons than the protection of the environment.
Our results have important theoretical implications. While studies examined to
what extent engaging in one sustainable behaviour would affect the likelihood that people engage in subsequent sustainable behaviour (i.e., spillover, Thøgersen & Crompton, 2009; Truelove, Carrico, Weber, Raimi, & Vandenbergh, 2014; Dolan & Galizzi, 2015; Nilsson, Bergquist, & Schultz, 2017), little is known about the
underlying processes and factors influencing the likelihood of positive and negative spillover. Our findings suggest that the motivation to engage in a behaviour (in our case adoption of SET) may play a key role in promoting positive spillover effects. Yet, given the correlational design of the studies in Chapter 2, one should be careful with drawing causal conclusions. It may be that people with a strong environmental self-identity are more likely to adopt an EV for environmental reasons and to engage in different pro-environmental behaviours. In Chapter 2 we argued, based on the compatibility principle (Ajzen & Fishbein, 1970) and a few experimental studies that provide circumstantial support, that our proposed causal chain seems likely. Yet, experimental studies are needed to test the proposed causal chain (i.e. to exclude reverse causality) and to ensure the positive relationship between environmental motivation to engage in behaviour, environmental self-identity and the engagement
in different pro-environmental behaviours is not explained by other causes, such as an omitted variable or a common source (Antonakis, Bendahan, Jacquart, & Lalive, 2010). For example, we did not include biospheric values, which predict
environmental self-identity (Van der Werff, Steg, & Keizer, 2014b) and possibly correlate with motivation to engage in behaviour too. Hence, we may not have accurately estimated the relationship. In addition, in Chapter 2 we measured all variables at one single point in time. People may strive for consistency between their answers on their environmental motivation, environmental self-identity and the extent to which they engage in different pro-environmental behaviours. Hence, the relationship could have been influenced by a common source (Antonakis et al., 2010).
Hence, experimental studies are needed to draw firm causal conclusions on
whether engagement in a certain sustainable behaviour for environmental reasons indeed increases the likelihood of positive spillover to other sustainable behaviours via environmental self-identity. For example, future studies could aim to strengthen environmental (versus financial) reasons for engagement in daily user behaviour (e.g. reducing thermostat settings or water use, and subsequently test whether this
promotes engagement in other sustainable behaviours by strengthening environmental self-identity. Moreover, our scale measuring energy efficient
investment behaviour consisted of energy behaviours people rarely engage in, such as purchasing energy efficient products or installing insulation. These behaviours may be a less appropriate proxy for people’s willingness to change their behaviour to improve sustainability than direct and indirect energy saving behaviours, as energy efficient investment behaviour may be less costly in terms of effort. Moreover, these behaviours may also not be that costly in terms of finances, as the samples consisted of early adopters, which are characterized by a relatively high income (Rogers, 2010; Plötz, Schneider, Globisch, & Dütschke, 2014). Future studies could include a broader range of items measuring direct and indirect energy saving behaviours.
Does not acting in line with planned sustainable SET use affect the way people perceive themselves and the motivation to adopt SET?
In Chapter 3 we studied to what extent people intend to use their SET in a sustainable way prior to the adoption of SET, and whether this differs from their actual SET use once the SET are adopted. As a case in point, we focused on the adoption of PV. We
reasoned that differences between intended and actual sustainable PV use could have implications for the way people perceive themselves and for the reasons they ascribe to having adopted PV. Specifically, we reasoned that people are likely to base their judgement about how sustainable they are by comparing their behaviour to a reference point (cf. Tversky & Kahneman, 1974). We reasoned that the intention to use PV in a sustainable way may function as a reference point against which one’s sustainable PV use is judged. Next, as people are motivated to be or to appear consistent and to align their cognitions, such as the way they see themselves, with their actions (Van der Werff, Steg, & Keizer, 2013b, 2014a, 2014b; Kashima,
Paladino, & Margetts, 2014; Steg, 2016), we hypothesized that a potential discrepancy between anticipated and actual sustainable PV use may affect the extent to which people see themselves as a sustainable PV user. Specifically, when people use PV in a less sustainable way than intended, they are less likely to see themselves as a
sustainable PV user. Conversely, their sustainable PV identity may be strengthened when they use the PV in a more sustainable way than they anticipated.
Furthermore, we examined whether a potential discrepancy between the
intended and actual sustainable use of SET may affect the extent to which people see themselves as a person who acts pro-environmentally in general (i.e. their
environmental self-identity). It may be that discrepancies between intended and actual sustainable PV use will merely influence one’s identity related to this specific behaviour (i.e., sustainable PV identity) and not one’s general environmental self-identity, as research has shown that environmental self-identity is particularly affected when people realise that they engaged in many different (un)sustainable behaviours (Van der Werff et al., 2014a). Hence, a discrepancy between intended and actual PV use may not have implications for one’s general environmental
self-identity, particularly if the level of engagement in other types of sustainable energy behaviour would remain the same.
A discrepancy between intended and actual use of PV may additionally affect
the reasons people ascribe to their decision to adopt PV (i.e., adoption motivation) due the aforementioned desire to be or to appear consistent. Specifically, when people use their PV in a more sustainable way than anticipated, their sustainable PV identity and maybe even their environmental self-identity could be strengthened, which may make people more likely to think that environmental reasons played an
important role in their decision to adopt PV than they indicated beforehand. In contrast, when people use their PV in a less sustainable way than anticipated, they may perceive themselves as a less sustainable PV user and maybe even a less sustainable person in general, which may make them less likely to think that environmental reasons played an important role in their decision to adopt PV than they indicated beforehand.
Chapter 3 reports the results of a longitudinal study among solar photovoltaics
(PV) adopters who received a subsidy to install PV. We assessed the way people perceive themselves, their motivation to adopt PV, and the level of engagement in different sustainable behaviours, including sustainable use of PV (i.e. adjusting energy use to match the self-generated PV energy supply) both before and after respondents’ adopted PV. Specifically, we included two indicators of the way people perceive themselves: to what extent they believe the adoption of PV makes them a sustainable person (i.e. sustainable PV identity) and to what extent they see themselves as a person who acts pro-environmentally (i.e. environmental self-identity). Furthermore, we included two indicators of motivation to adopt PV: the extent to which PV is expected to benefit the environment and the importance of these environmental consequences for the decision to adopt PV (cf. environmental beliefs and evaluations, respectively, Ajzen & Fishbein, 2000).
First, the results showed that after the adoption of PV, the vast majority of
participants used their PV in a less sustainable way than anticipated. This may have detrimental consequences for the sustainable energy transition, as PV are more likely to realise their full potential when people use them in a sustainable way, by matching their energy demand to the energy production of their PVs as much as possible (Geelen, Reinders, & Keyson, 2013).
Importantly, the discrepancy between intended and actual PV use affected the
way people perceive themselves. More specifically, after the adoption of PV, people were less likely to see themselves as a sustainable PV user. In addition, the stronger the discrepancy between intended and actual sustainable use of the PV, the less likely people were to see themselves as a sustainable PV user. However, people’s general environmental self-identity did not differ before and after installing PV. Yet, interestingly, we did find that the larger the discrepancy between people’s intention to use PV in a sustainable way and their actual sustainable PV use, the weaker their environmental self-identity after the installation of PV.
Future research is needed to study why environmental self-identity did not change after installing PV, while the strength of the discrepancy between intended and actual sustainable use is related to environmental self-identity. As a strong environmental self-identity promotes the engagement in wide ranging sustainable behaviours, while a weak environmental self-identity may inhibit consistent sustainable actions (Van der Werff et al., 2013a, 2013b, 2014a, 2014b; Peters et al., 2018), it is important to study factors that affect the strength of environmental self-identity. The finding that environmental self-identity did not change after installing PV may be explained by the finding that people did not change the extent to which they engaged in other pro-environmental behaviours before versus after the adoption of PV. As such, our findings are in line with previous studies showing that
environmental self-identity is relatively stable, and only changes when people realise that they engage in many different (un)sustainable behaviours, or behaviours that were relatively expensive and unique (Van der Werff et al., 2014a). It is important that future studies examine whether the extent to which people engage in other sustainable behaviours may act as a ‘buffer’, preventing the discrepancy between intended and actual sustainable SET use to affect environmental self-identity.
Moreover, the results suggest that after the installation of PV respondents were
less likely to believe PV have positive environmental consequences than before the installation of PV (i.e. environmental PV beliefs). Yet, people’s evaluation of the importance of these environmental consequences of PV (i.e. environmental PV evaluations) in their decision to apply for the subsidy to install PV did not change. Furthermore, both environmental PV beliefs and PV evaluations after the installation of PV were not significantly related to the discrepancy between intended and actual sustainable PV use.
To summarize, the discrepancy between the intention to use PV in a
sustainable way and actual sustainable PV use seem to particularly affect the way people perceive themselves, namely people’s identity related to the specific behaviour (i.e. sustainable PV identity) and people’s general environmental self-identity, but not the motivation they ascribe to adopting PV. Our findings suggest that people indeed base their judgements about how sustainable they are by comparing their behaviour to a reference point (cf. Tversky & Kahneman, 1974), in this case the intention to engage in sustainable behaviour. This may be explained by the motivation to be or to appear consistent: people are motivated to align the way they see themselves to their
observed behaviour (Cialdini, 1984; Guadagno & Cialdini, 2010). As such, our findings are in line with theories that are based on the consistency principle (i.e. cognitive dissonance theory (Festinger, 1957) and self-perception theory (Bem 1972).
Our results suggest that it is important to empower and enable people to act
upon their intention to use their PV in a sustainable way, as this may have
consequences for how people see themselves. For example, specific guidelines can be provided on how people can adjust their energy demand to match the energy
produced by their PV. Furthermore, people could be encouraged to adopt energy management systems, that automatically shift on or off household appliances, such as dishwashers or washing machines, depending on the self-generated energy
production (Kobus et al., 2013; Sintov & Schultz, 2015). Household equipment can even be controlled and operated remotely, for example by distribution system operators. The question remains whether people are willing to adopt such appliances and programmes, because people may be concerned about their privacy and
autonomy (Sintov & Schultz, 2015). Future research is needed to examine how consumers can best be empowered to act upon their intention to use their PV in a sustainable way.
Future research could study why people used their PV in a less sustainable way
than anticipated before the installation of PV. It may be that participants were not sufficiently motivated to adjust energy demand to match the production of self-generated solar energy. More specifically, it may be that the environmental
motivation to adopt PV was not the strongest motivator to adopt SET, as for example financial (the PV system was heavily subsidized) motivations may have been stronger among our sample. An alternative explanation may be that matching energy demand to the production of self-generated solar energy is too costly in terms of effort or time. Indeed, studies suggest that sustainable use of sustainable energy technologies may prove more challenging than people anticipated (Schmalfuss et al., 2015; Schick & Gad, 2015; Smale et al., 2017).
Even though we started with a large number of participants (N = 491) and we
achieved satisfactory response rates for both waves, we still ended up with a relatively small sample that completed the questionnaire in both waves (N = 74). This is typical in longitudinal studies. Yet, future research could test our reasoning among bigger samples to test the robustness of our findings.
Can the engagement in sustainable SET use and other sustainable behaviours be promoted by emphasizing the environmental benefits of SET?
In Chapter 2 we found that people may be more likely to use SET in a
sustainable way and to engage in other sustainable behaviours when they adopt SET for environmental reasons, as the environmental motivation to adopt SET is
positively related to one’s environmental self-identity. These findings suggest that the environmental motivation to adopt SET might be key in promoting consistent
sustainable behaviour, including sustainable SET use. A next question is whether and how the environmental motivation to adopt SET could be strengthened.
We proposed that environmental motivation to adopt SET may be
strengthened by information on the environmental benefits of SET. More specifically, we argued that emphasizing the environmental benefits of SET may make it more likely that people realise SET have environmental benefits, which may increase the likelihood that people are motivated to adopt SET for environmental reasons (i.e. stronger environmental motivation to adopt SET). Subsequently, when people are more strongly motivated to adopt SET for environmental reasons, the adoption of SET is more likely to signal that they are a pro-environmental person (i.e. stronger pro-environmental signalling value of SET), thereby strengthening the extent to which they see themselves as an environmentally friendly person in general (i.e. environmental self-identity). In turn, a strengthened environmental self-identity may promote sustainable SET use and the engagement in other sustainable behaviours, due to the aforementioned motivation to be consistent. In contrast, when financial benefits of SET are emphasized, people are probably not more likely to realise that SET have environmental benefits, which implies that the motivation to the
environmental motivation to adopt SET will not be strengthened. Therefore, the adoption of SET may not signal that one is a pro-environmental person, and
environmental self-identity will not be strengthened, making sustainable SET use and the engagement in other sustainable behaviours not more likely.
As answering questions on these process variables may influence responses on
the outcome variables, and vice versa, regardless of the effect of the manipulation, we tested our line of reasoning in two separate experimental studies. We first tested the
effect of appeals emphasizing environmental versus financial benefits of SET on the intention to use SET in a sustainable way and to engage in other sustainable behaviours (Study 1). Second, we tested the effect on relevant underlying process variables: motivations to adopt SET, pro-environmental signalling value of SET and environmental self-identity (Study 2) and added a control condition.
In both studies we asked the respondents to imagine they would adopt a SET
(Study 1: a smart technology that automatically turns household appliances on and off to match their energy demand to the available supply of energy; Study 2: PV). Subsequently they read about either the environmental benefits of the technology (environmental condition) or financial benefits of the technology (financial condition) or no benefits (control condition, only in Study 2). Contrary to our expectations, the results showed that emphasizing environmental versus financial benefits of a SET did not increase the likelihood that people engage in sustainable SET use and other sustainable behaviours (Study 1), nor did it affect the motivation to adopt SET (i.e. beliefs and evaluations about the consequences of SET), the pro-environmental signalling value of SET and pro-environmental self-identity (Study 2) compared to financial appeals or the control condition.
We proposed two alternative explanations for these findings. The first
explanation relates to our research design. In our study we focused on hypothetical rather than actual SET adoption. Specifically, asking people to imagine to engage in SET adoption may not be effective, as people may be more likely to ascribe
engagement in behaviour to themselves (and hence affecting our assumed process variables) when they actually engage in behaviour. Future studies could focus on people who are about to adopt SET and test, prior to the adoption of SET, whether emphasizing environmental (versus financial) benefits of a SET affects the motivation to adopt SET. Subsequently, once the SET are adopted, one could test whether the pro-environmental signalling value and environmental self-identity change, as well as the likelihood to use sustainable in a sustainable way and to engage in other
sustainable behaviours. When it is not possible to reach such a sample of future adopters of SET, attempts could be made to make the hypothetical choice more realistic. For example, virtual reality could be used to increase engagement and involvement of people in the hypothetical choice situation, which may strengthen the impact of the manipulation.
Second, the manipulation may have had wider effects. We asked people to imagine to engage in sustainable behaviours and subsequently emphasized either the environmental or financial benefits of the behaviour. Yet, imagining to engage in a certain behaviour may stimulate people to think about other advantages as well, rather than solely focussing on the environmental versus financial benefits that were emphasized in the studies. Imagining to engage in the behaviour may even stimulate people to think about disadvantages. For example, in Study 1 concerns regarding autonomy and privacy (Sintov & Schultz, 2015) could have prevented the positive effect of emphasizing environmental versus financial benefits on our dependent variables to occur. In Study 2, autarky and social status benefits might have played a more important role than environmental or financial benefits (Noppers et al., 2014; 2015; Korcaj et al., 2015). Our results showed that it may indeed be the case that people were prompted to think about other advantages as well, as only half of the participants focused solely on the benefits addressed in the information.
Future studies could focus on novel SET that people do not know yet. This way,
it may be less likely that people are prompted to think about other (dis)advantages than addressed in the study. In addition, tailoring the informational appeals to important values may be more effective. A study has shown that stressing
environmental disadvantages of behaviour was more effective when people valued the environment (e.g. endorsed biospheric values; Bolderdijk, Gorsira, Keizer & Steg, 2013). Future research could study whether these findings with curtailment behaviours can be replicated by studying the adoption of SET. More specifically, research could study whether emphasizing environmental advantages of SET will promote sustainable SET use and the engagement in other sustainable behaviour especially among people who strongly endorse biospheric values.
Limitations and future directions
In Chapter 2 and 3 our samples consisted of actual adopters of SET. These samples may not be representative of the general population, yet they are representative for early adopters of SET. Indeed, they consisted of mostly male respondents with a high income and education level which are typical characteristics for early adopters (Rogers, 2010; Plötz, Schneider, Globisch, & Dütschke, 2014). Therefore, our results are likely to have a high external validity. Conducting studies among samples
consisting of actual adopters of SET is an important contribution to the literature, as studies are often conducted among young, female (psychology) students. Future studies could include more general samples.
Yet, an important consequence of these correlational field studies is that
causality cannot be established in Chapter 2 and 3. Hence, one should be careful with drawing causal conclusions. The results in Chapter 2 suggest it may be particularly important to strengthen environmental motivation to adopt SET in order to promote sustainable SET use and other sustainable behaviours. To explore causality, future research could manipulate different types of motivation to adopt SET and examine whether this indeed affects the way people perceive themselves as well as subsequent sustainable behaviours. Yet, our approach in Chapter 4, in which we emphasized either environmental or financial benefits of SET that people imagined to adopt did not promote intended sustainable SET use or the intention to engage in other sustainable behaviours, nor did it affect (among other) environmental motivation to adopt SET. Perhaps tailoring the informational appeals to important values will be more effective. A study has shown that stressing environmental disadvantages of behaviour was more effective when people valued the environment (e.g. endorsed biospheric values; Bolderdijk, Gorsira, Keizer & Steg, 2013). Future research could study whether emphasizing environmental benefits of SET will promote sustainable SET use and the engagement in other sustainable behaviour especially among people who strongly endorse biospheric values.
The results in Chapter 3 suggest that a discrepancy between intended and
actual sustainable SET use influences the way people perceive themselves and the motivation they ascribe to engage in the behaviour. To test causality a group with participants who behave in a more sustainable way than intended can be compared with a group of participants who behave in a less sustainable way than intended.
More generally, future research could test other ways to promote consistent
engagement in sustainable behaviour, including sustainable SET use, among those who adopted SET, for example by strengthening one’s environmental self-identity directly by providing people with feedback on the extent to which they are an environmentally friendly person. Research has shown that this intervention type is successful to promote engagement in different sustainable behaviours (Van der Werff et al., 2014a, 2014b), but has not been applied to the adoption of SET. Hence, the question remains whether people believe that the adoption of SET makes them a
sustainable person. Future research could test, once people have adopted SET, whether feedback emphasizing that the adoption of SET makes one a pro-environmental person affects pro-environmental self-identity and the likelihood of sustainable SET use as well as other future sustainable behaviour. For example, smart devices or apps that are connected to a smart meter could provide this type of
feedback (Kobus et al., 2013; Sintov & Schultz, 2015).
Furthermore, in Chapter 2, 3 and 4 we relied on self-reported data on the engagement in behaviour, that is sustainable SET use and engagement in other sustainable behaviours. People’s self-reported behaviour may differ from people’s actual engagement in behaviour (Gatersleben, Steg & Vlek, 2002; Kormos & Gifford, 2014). Hence, to test the robustness of our findings future studies could include measures of actual use of self-generated solar energy, and the use of energy from the regular grid.
Practical implications
Our results have several practical implications. First, our results suggest it may be particularly important to strengthen environmental motivation to adopt SET (rather than for example financial motivation to adopt SET) in order to promote the
sustainable energy transition. Specifically, people seem more likely to use their SET in a sustainable way and to consistently engage in other sustainable behaviours when people adopted SET for environmental reasons via one’s environmental self-identity. Hence, policy makers could strengthen environmental rather than financial or technological SET adoption motivations, as people seem more likely to use their SET in a sustainable way and to consistently engage in other types of sustainable
behaviour when people adopted SET for environmental reasons. Yet, the findings in Chapter 4 show that strengthening environmental motivation to adopt SET may not be that easy. As mentioned above, future research is needed to examine how environmental motivations to adopt SET can be strengthened.
Furthermore, we found that the vast majority of people use their SET in a less sustainable way than they intended prior to the adoption. This is a very important finding, as SET are more likely to realise their full potential when people use them in a sustainable way. Moreover, the discrepancy between intended and actual
sustainable SET use affected the way people perceive themselves, in particular people’s sustainable PV identity and their environmental self-identity. A stronger
environmental self-identity is likely to promote the engagement in a wide range of sustainable behaviours, while a weaker environmental self-identity may inhibit consistent sustainable actions (Van der Werff et al., 2013a, 2013b, 2014a, 2014b). Hence, when individuals fail to act in line with their intentions, they may be less likely to engage consistently in sustainable behaviours in the future.
As such, our findings denote the importance of empowering and enabling
people to act in line with their anticipated sustainable use of SET. For example, clear guidelines can be provided on how people can adjust their energy demand to match the energy produced by their PV. More specifically, distribution system operators and/or energy suppliers can inform their customers on general patterns of demand and supply, accompanied with general tips (e.g. try to avoid energy use in the late afternoon/early evening) or tailormade tips (e.g. on the basis of their smart metering data) on how to shift energy use. People could also be encouraged to adopt energy management systems that automatically turn on or off household appliances, such as dishwashers or washing machines, depending on the self-generated energy
production (Kobus et al., 2013; Sintov & Schultz, 2015).
Conclusions
In the current PhD dissertation, we studied whether and how SET adoption is related to sustainable SET use and the engagement in other sustainable behaviours, and how the engagement in other sustainable behaviours, including sustainable SET use, can be promoted. We argued and found that a strong environmental motivation to adopt SET is positively related to the consistent engagement in sustainable behaviours via environmental self-identity. Furthermore, we found that prior to the adoption of SET, people intend to use SET in a sustainable way. Yet, once the SET are installed the majority of people use the SET in a less sustainable way than anticipated. Moreover, this discrepancy between intended and sustainable SET use even affected the way people perceived themselves: the stronger the discrepancy between intended and actual sustainable use of the SET, the less likely people were to see themselves as a sustainable SET user and an environmentally friendly person in general.
The findings in current dissertation suggest that it is important to strengthen
the environmental motivations to adopt SET in order to promote consistent sustainable behaviour, including sustainable SET use. Yet, informational appeals emphasizing environmental rather than financial benefits, were not successful in
promoting consistent engagement in sustainable behaviour, nor did it affect the motivation to adopt SET, pro-environmental signalling value of SET and
environmental self-identity. Future research could study other ways to strengthen the environmental motivation to adopt SET, or environmental self-identity. Second, our findings suggest that, after the adoption of SET, it is important to help people to act in line with their planned SET use. Future research can study the most effective strategies to empower people to act upon their sustainable intentions.
