Frankfurt (Germany), 6-9 June 2011 W. Niederhuemer – Austria – RIF Session 4 – Paper PROBABILISTIC PLANNING FOR A HIGHER INTEGRATION OF WIND TURBINES TO MV DISTRIBUTION NETWORKS Walter Niederhuemer Karl Derler Linz Strom Netz GmbH

Frankfurt (Germany), 6-9 June 2011 W. Niederhuemer – Austria – RIF Session 4 – Paper Introduction  Feed in by onshore wind turbines into MV-grids is a particular challenge for the DSO Requests for connections primarily for several wind turbines or small wind farms Power range of a few MW Connections distributed across the same part of the MV- distribution network  To enable the feed in and guarantee the power quality Reduction of the installed feed in power is necessary Extending the distribution network

Frankfurt (Germany), 6-9 June 2011 W. Niederhuemer – Austria – RIF Session 4 – Paper Introduction  Producer and DSO with different optimum Producer  Deliver full feed in power at any time  Increase the energy output and thus to optimize the return  Low direct grid connection costs DSO  Keep the network cost as low as possible  To support the objectives of the EU and to enable more feeding in, it is necessary To find an overall economic optimum To find a compromise between network investments and produces energy quantity

Frankfurt (Germany), 6-9 June 2011 W. Niederhuemer – Austria – RIF Session 4 – Paper Method of calculation  Probabilistic calculation  Taking into account the statistical behavior of Output voltage in the substation Current in the branch Feed in power of the wind turbine

Frankfurt (Germany), 6-9 June 2011 W. Niederhuemer – Austria – RIF Session 4 – Paper Result of the conventional assessment  Reduction of installed feed in power to 2,2 MW is necessary  Alternatively, 0,5Mio€ investment to the grid for a 3km long MV cable  Selected network 1,2MW wind turbine + 250kW biogas plant connected New 2MW wind turbine is planned Connection via 17,5km overhead line 95mm² Aldrey  Conventional assessment Peak load with and without feeding Off-peak load with and without feeding

Frankfurt (Germany), 6-9 June 2011 W. Niederhuemer – Austria – RIF Session 4 – Paper Result of the probabilistic calculation  Installed wind turbine power 3,2MW  Voltage exceeds the voltage limit only for a few hours.  Theoretically generated annual amount of energy about MWh  With active power control 0,03% not feed in energy Reduction of active power up to max. 1370kW  Annual revenue loss is less than 100€ (with feed-in tariff of 9,6ct/kWh)

Frankfurt (Germany), 6-9 June 2011 W. Niederhuemer – Austria – RIF Session 4 – Paper Result of the probabilistic calculation  Theoretically generated annual amount of energy about MWh  With active power control 5% not feed in energy Real feed in energy MWh Reduction of active power up to max. 3,8MW (50% of installed feed in power)  2 times higher energy yield without additional grid investments  If a not feed in energy amount of 5% is acceptable for producers 7,5MW wind turbine power could be installed at the PCC Yearly earning of energy of on-shore wind turbines and loss because of control or switch off if voltage level is too high

Frankfurt (Germany), 6-9 June 2011 W. Niederhuemer – Austria – RIF Session 4 – Paper Conclusion  Probabilistic planning allows a better simulation of real network conditions  More than 2 times higher generation capacity by minimal network costs  Acceptance by producers of a certain amount of not feed in energy is necessary  Need of construction cost contribution for future grid investments  Need of suitable legal frameworks