As a consequence of cost-competitiveness of renewable energy technologies, the investments in these energy sources are becoming more and more significative. To be effective, these investments will require to make the energy system more secure and sustainable, by reducing the risks for investors in the emerging sectors. In this transition towards a wider use of renewable energy sources, there are mainly three main challenges that should be overcome in the near future: 1) policy and regulatory uncertainty; 2) high investment risks in developing countries; and 3) system integration of wind and solar in some countries. Integration of renewables into the system and market mechanisms requires an in-depth discussion and understanding by those that are designating to ensure well-functioning of the market. The joint workshop was an occasion to elaborate in detail how TSOs/DSOs and Regulators from the ECRB and MEDREG region deal with challenges that RES are bringing to the system. The discussions from the workshop will be shared within the MEDREG and ECRB communities as a further contribution to our ongoing efforts to facilitate and develop a common regulatory culture and a regionally coherent approach to specifically renewable energy market regulation in the Mediterranean region and Energy Community.