What happens after positive tipping points? A socio-technical analysis of acceleration and deceleration in solar-PV diffusion in Germany and the UK

This paper contributes to debates on positive tipping points in climate mitigation, which are relevant for accelerating low-carbon transitions. The first contribution is to draw attention to dynamics after the tipping point and criticise the determinism of existing approaches, which excessively focus on irreversible self-reinforcing processes. We conceptually extend Geels and Ayoub's socio-technical perspective on tipping points by adding potential negative feedback processes on political and socio-cultural dimensions that can decelerate further diffusion after the tipping point. The second contribution is to replicate Geels and Ayoub's framework with two new case studies and thus enhance its empirical validity. The case studies are solar-PV diffusion in Germany and the UK, which both first accelerated because of positive feedbacks and then slowed down because of negative feedbacks. We explain why solar-PV diffusion almost entirely halted in the UK but regained momentum in Germany after 2016. Our findings demonstrate the importance of analysing both positive and negative feedbacks in low-carbon transitions. Our findings also show that the strength of various feedback processes is shaped by broader economic and political contexts.