In recent years Distributed Generation (DG) have become increasingly widespread, especially from Non-Programmable Renewable Sources (NPRES), and certain technologies have grown and replaced other energy vectors (e.g., electric vehicles, heat pumps). This has required the function of the distribution grid to evolve and become a ‘facilitator’ of new market mechanisms while continuing to ensure system resilience as well as continuity and quality of supply. Moreover, there is a shared expectation of ancillary service market participation for to expand to generation from non-programmable renewable sources and GD, and eventually also to loads and storage systems. However, the roles of the different actors and the mutual interactions are yet to be determined, in particular the way Distribution System Operators (DSO) may reconcile the provision of services (of a global nature) by GD with (local) requirements on the quality of supply.

In addition, the significant increase in the penetration of Renewable Energy Sources (RES), often through small-scale generators connected to the distribution grid, may prospectively increase the difficulties in electricity system operation.

These issues were also the focus of the 2018 Annual Implementation Plan, in continuation of the three-year research project ‘Evolution and Development of Distribution Grids’ in the 2018 Annual Implementation Plan.

In 2018, the activities carried out in the previous three-year period were deepened revolving around the themes of recommendations on optimal management of active distribution grid, Distributed Generation’s participation in ancillary services (in synergy with the EU SmartNet and EUSysflex projects), and co-simulation for active distribution grids.

As regards optimal management of active distribution grids, the calculation ofequivalent capabilitywas integrated into the SARA platform. Equivalent capabilityis a useful indicator for quantifying the ability of resources to participate in the ancillary service market.

Regarding the participation of Distributed Generation in ancillary services, results of European activities on the SmartNet and EUSysflex projects were summarised.

Regarding co-simulation for active distribution grids, improvements were made to the software (automation of the radial/meshed grid management alternative, facilitation of the construction of new examples with improvement of of grid description input modes).