Zero carbon homes in the UK? Analysing the co-evolution of policy mix and socio-technical system.

• This paper applies a novel analytical co-evolutionary framework for the first time empirically. • The analysis focuses on the zero carbon homes policy mix in the UK. • The paper produces novel insights about the effects of policy mix credibility on socio-technical change. • The paper proposes conceptual refinements to the co-evolutionary framework about the interaction of exogenous conditions. Understanding how policy and policy-making processes can influence the speed and direction of socio-technical change is an important, yet underexplored research agenda in the field of sustainability transitions. This paper is the first application of a novel analytical framework which conceptualises the co-evolutionary dynamics of policy mixes and socio-technical systems, by complementing the sustainability transitions and policy mix literatures with insights from policy feedback theory. Our paper is an in-depth empirical case study of the zero carbon homes policy mix in the UK which sought to promote radical change in the UK house building system. Our paper makes three contributions. First, it makes an empirical contribution by analysing an example of an ambitious policy strategy in the housing sector where various policy effects and feedback mechanisms led to a loss of political support for the target, eventually leading to its abandonment, and only limited change within the socio-technical system. Second, our paper produces novel insights about the effects of policy mix credibility on socio-technical change, and the underlying feedback mechanisms which influence its formation and loss. Finally, based on our empirical analysis we propose conceptual refinements to the co-evolutionary framework and suggest avenues for future research explaining the dynamics of feedbacks between policy mixes and socio-technical systems. From the empirical analysis a key finding is that policy mixes need to be effectively designed in order to produce positive feedback from the outset, through the creation of resources, provision of clear information and the creation of credibility, and reforming conflicting institutional supports. In the case, ineffective initial design led to uncertainty and inertia, which did not generate sufficient positive feedback to withstand adverse economic and political conditions later on, which ultimately contributed to the abandonment of the policy mix. [ABSTRACT FROM AUTHOR]