The overall objective of SOLARROK is to deepen the transnational cooperation between leading European research-driven clusters in the Photovoltaic (PV) sector. To gain a competitive position and to foster industrial innovation, EU research infrastructures require more and more resources: multidisciplinary competencies, investments for technical equipments, skilled human resources, and strong links to the business community. To this end, research centers in Europe join with competitive companies and public authorities, forming research driven clusters. Within the SOLARROK cluster cooperation, four general objectives have been defined:(1) Developing joint business models to improve access to international markets for RTD and business actors of the European solar sector; (2) Supporting the innovation system by (i) filling RTD-gaps to improve resource-efficient production of solar modules, (ii) identifying sustainable cluster approaches, (iii) exchanging cluster management best practices; (iv) benchmarking in international context; (3) Building international collaboration capacities by knowledge exchange activities within and beyond Europe and increasing researcher mobility between research and industry; (4) Strengthening European competitiveness by developing an international level Joint Action Plan including regional smart specialisation strategies. SOLARROK is a CSA jointly elaborated by leading clusters in Spain, France, Germany, Belgium and the Netherlands, Lithuania and Austria, plus industry and research partners in Slovenia and Norway. A three step approach (mapping of existing resources, interactive mutual learning, and a focused integration process) will lead to a Joint Action Plan, involving European key-stakeholders. Following a bottom up approach and utilising direct involvement of Regional Authorities, the JAP will ensure a comprehensive implementation. SOLARROK expands the cooperation, exchanging methodologies and strategies with other EU PV clusters.