This paper examines the emergence of 1,072 solar initiatives (268 associations and 804 cooperatives operating photovoltaic systems) from 2006 to 2018 in Germany. The study draws on organizational ecology theory to identify factors that influence the likelihood of establishing a solar initiative by investigating the impacts of two opposing effects: legitimation effects and competition effects. We show that the density of medium-scale photovoltaic installations in a district negatively affects the likelihood of establishing a solar initiative, suggesting that competitive dynamics prevail between different market entrants, dampening the emergence of solar initiatives. By contrast, we find that the founding of a solar initiative in a district has a positive effect on the probability of founding other solar initiatives in the same district, confirming legitimacy effects. Further, we show that solar initiatives are more likely to be founded in rural areas, especially in densifying rural areas.