Economic grid support from variable renewables

Grid support in the form of ancillary services will need to be supplied to an increasing extent by variable renewables, as these are replacing non-variable conventional generation. Opportunities and boundary conditions for cost-efficient provision are determined by many factors, including technology as well as operational and economical aspects that depend on energy market design. Wind and solar PV energy include a broad range of power plants, from small distributed PV to large concentrated offshore wind farm clusters. There are specific issues for transmission and distribution systems, and also how to coordinate system service provision from distribution systems to transmission system. The paper summarizes the assessment of the above issues within the EU project REserviceS, finalised in September 2014. It also presents REserviceS recommendations for enabling market mechanisms for provision of grid support services in European power systems