Smart Grids for Optimised Utilisation of Renewable Energy Supply

Future energy systems will increasingly rely on dis tributed and renewable energy sources (RES). Elect rical feed-in of photovoltaic (PV) power plants and wind energy c onverters (WEC may vary greatly, the supply of elec trical power from RES and the demand for electrical power are not per se matching. and in addition, with a growi ng share of generation capacity especially in distribution grid s, the top-down paradigm of electricity distributio n is gradually replaced by a bottom-up power supply. This altogether leads to new problems regarding a safe and reliabl operation of power grids. In order to address these challenge s, th notion of Smart Grids has been introduced. I n this context, autonomous agents and the concept of self-organisin g systems are key elements in order to intelligentl y use the inherent flexibilities of distributed generators, pow er storage systems and power consumers. Our researc h goal is to optimise the local utilisation of RES feed-in in a given power grid by intelligently integrating both supply and demand management measures and with special respect t o the electrical infrastructure. In this paper fir st we show how an intelligent load management system for battery c harging/discharging of electrical vehicles EVs can increase the locally used share of supply from PV systems in a l ow voltage grid. For a reliable demand side managem ent of large sets of appliances dynamic clustering is necessary. We show how control of such clusters can affect lo ad peaks in distribution grids. Additionally we give a short ov er iew how we are going to expand an attempt of sel f-organised clusters of units to a virtual control centre for a dynamic virtual power plant. 1. Supply-demand-matching considering renewably energy sources Future energy systems will increasingly rely on dis tributed and renewable energy sources (RES). In 203 0, between 50% (BMWi 2010) and 67% (BMU 2012) of the g ross electricity demand of Germany are expected to be covered by electric feed-in from RES; in 2050, this share is expected to grow up to 85% (BMU 2012). In course of this politically driven ev olution of an energy system, new challenges regardi ng the successful and sustainable integration of RES b oth into the power grid and into energy markets hav e to be addressed: As photovoltaic (PV) power plants and wi energy converters (WEC) rely on solar radiation and wind, respectively, their electrical feedin may vary greatly and unforeseen in small amounts of time (stochastic fluctuation of RES feed-in). In ad dition, the supply of electrical power from RES and the demand for electrical power are not per se matching , that is there are times of high electrical feed-i n and low power demand, vice versa. Even with today’s com paratively low share of RES, these situations may yield negative electricity prices at the European E nergy Exchange (EEX) (Wissing 2012) due to the (short-term) surplus of power generation. Regarding the electrical infrastructure, the integration of RES increases the strain on power grid assets (e.g. pow er transformers) as today’s power grids where histo rically designed for a top-down power transmission and d istribution. With a growing share of generation capacity especially in distribution grids, the top-do wn paradigm is gradually replaced by a bottom-up po wer supply, leading to new problems regarding a safe an d reliable operation of power grids (e.g. voltage c ontrol and power grid protection measures). 1 University of Oldenburg, Department of Computing Sc ien e, D-26111 Oldenburg, email: Michael.Sonnenschein@Uni-Oldenburg.DE 2 OFFIS Institute for Information Technology, Escher w g 2, D-26121 Oldenburg email: {Martin.Troeschel | Ontje.Luensdorf}@OFFIS.D E, Internet: http://www.offis. de EnviroInfo 2013: Environmental Informatics and Renewable Energies Copyright 2013 Shaker Verlag, Aachen, ISBN: 978-3-8440-1676-5