In response to the challenges of security of supply, environmental sustainability and competitiveness, which underpin the European Union (EU) integrated climate change and energy policy, the electric power sector in Europe is facing several modifications and developments towards targets for 2020 and beyond. In this context, the Distributed Generation (DG) technologies - often based on Renewable Energy Sources (RES) or cogeneration (Combined Heat and Power, CHP) - here defined according to the EU regulation as the electric power sources connected to distribution grids, are expected to play an increasingly important role throughout Europe.
The present paper, after an overview on the EU policy background, reviews the current state and penetration of RES, CHP and DG technologies deployed around the EU Member States; then, it investigates the main technical issues towards the DG integration into the European power systems and their respective impacts. Afterwards, a revision of the impact of the current power system “status quo” is made and the grid planning issues that arise due to the DG presence are put forward.
The paper subsequently introduces the specific planning and development issues related to the Italian high voltage network, a 60-150 kV system, in presence of DG. The Italian TSO approach to this situation, described on this paper and named “Power Collector Method” is a method that allows the connection of a sizeable amount of DG, reducing congestions by reinforcing a limited length of the 150kV network and constructing new 380/150kV substations.