Adoption of smart energy technologies, such as electric vehicles (EVs), can significantly reduce fossil energy use, provided that adopters of an EV also use the EV in a sustainable way. Hence, it is key to understand which factors affect the likelihood that the adoption of EVs promotes the sustainable use of EVs, and promote consistent sustainable energy behaviours. We argue that the motivation to adopt an EV plays a key role in this respect. When people adopt an EV for environmental reasons, this will signal that they are a proenvironmental person, thereby strengthening environmental self-identity and promoting consistent sustainable energy behaviours. We conducted two cross-sectional studies among EV adopters to test our reasoning. As expected, the more people adopted an EV for environmental reasons, the stronger their environmental self-identity, in turn increasing the likelihood that they engaged in other sustainable energy behaviours. In contrast, adopting an EV for financial or technological reasons was not consistently related to environmental selfidentity and sustainable energy behaviours. These results suggest that the motivation for adopting an EV is crucial for the likelihood that people engage in sustainable energy behaviour consistently, which is key to realise a sustainable energy transition.

The combination of electric vehicles (EVs) and intermittent renewable energy sources has received increasing attention over the last few years. Not only does charging electric vehicles with renewable energy realize their true potential as a clean mode of transport, charging electric vehicles at times of peaks in renewable energy production can help large scale integration of renewable energy in the existing energy infrastructure. We present an agent-based model that investigates the potential contribution of this combination. More specifically, we investigate the potential e ects of di erent kinds of policy interventions on aggregate EV charging patterns. The policy interventions include financial incentives, automated smart charging, information campaigns and social charging. We investigate how well the resulting charging patterns are aligned with renewable energy production and how much they a ect user satisfaction of EV drivers. Where possible, we integrate empirical data in our model, to ensure realistic scenarios. We use recent theory from environmental psychology to determine agent behaviour, contrary to earlier simulation models, which have focused only on technical and financial considerations. Based on our simulation results, we articulate some policy recommendations. Furthermore, we point to future research directions for environmental psychology scholars and modelers who want to use theory to inform simulation models of energy systems.

To realize the full potential of solar photovoltaics (PV), PV adopters need to adapt their energy demand to the production of self-generated solar energy as much as possible (i.e., use their PV sustainably). In a longitudinal questionnaire study ( N = 74) in the Netherlands, we compared the intention to use PV in a sustainable way before the installation of PV with actual PV use. Wave 1 took place before respondents adopted PV, while Wave 2 took place after they installed PV. We examined whether potential differences between actual sustainable PV use and initial intentions may have implications for how people see themselves and for the motivation they ascribe to their decision to adopt PV. Our results show that the vast majority of people use their PV in a less sustainable way than they anticipated. Furthermore, after the installation of PV, respondents are less likely to see themselves as a sustainable PV user and less likely to believe that PV have positive environmental consequences than before the installation, while environmental self-identity did not differ pre and post-installation of PV. Moreover, 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 and as a person who acts pro-environmentally in general. These findings suggest that it is important to support people to use their PV in a sustainable way to facilitate them to act upon their intentions.

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