This paper develops an analytical approach to explore institutional barriers to spatial integration between renewable energy (RE) and other land use functions and provides insight into opportunities for institutional harmonization between involved policy domains. Spatial integration of RE with other land use functions provides opportunities to use limited amounts of space more efficiently, allowing for a more fluent roll-out of renewable technologies. However, such integration requires the involvement of various policy domains that are each guided by specific institutional frameworks, which are often tailored to specific sectoral needs. Therefore, spatial integration of RE and other land use functions requires institutional harmonization between involved policy domains. However, there is limited guidance in literature on how such harmonization does or could occur. Moreover, while literature on RE recognizes the merits of institutional approaches, it focuses on institutions as the formal rules of the game, often disregarding the agency component (the 'play of the game'). The analytical approach developed in this paper combines the Institutional Analysis and Development framework with insights from Discursive Institutionalism. The approach enables structured assessment of relationships within and between established institutions (the 'rules of the game') and actors' ideas, interpretations and deliberations regarding these institutions (the 'play of the game'), providing insight in processes of institutional harmonization. This analytical approach is applied to the case of spatial integration of photovoltaics with national transport infrastructure networks in the Netherlands. The findings from the case show that (1) insight in interrelations between institutional barriers is crucial for addressing institutional harmonization; (2) institutional harmonization within policy domains is a precondition for harmonization between policy domains; and (3) the agency component (play of the game) is key to successful harmonization. In conclusion, the analytical approach provides insight into the co-evolution between the rules of the game and the play of the game, which is pivotal to institutional harmonization. (C) 2018 Elsevier Ltd. All rights reserved.