This paper engages with recent research concerning the roles of niche spaces in the strategic management of sustainable innovations. Whilst a growing body of empirical investigation looks to developments within these spaces, it is surprising how little pauses to consider how the spaces themselves develop over time, what constitutes these spaces, and how their characteristics influence sustainable innovation. We explore such questions through a case study into the history of solar photovoltaic electricity generation over the last 40 years in the UK. Whilst we see evidence consistent with recent ideas about niche spaces shielding, nurturing, and empowering sustainable innovation, the main thrust of our analysis concludes that this arises in contested and compromised ways. Moreover, our analysis identifies niche space developing through the political ability of technology advocates recursively interpreting, representing, and negotiating between the content and contexts of innovation.