Steps towards integration of PV-electricity into the GRID



The high growth rate of photovoltaic (PV) installations leads to the question about the consequences for grid integration and management. As a case study, we present an analysis of the first limits for the amount of PV electricity in the utility grid of the greater Zurich area. The first limit is found at an amount of 6% of the yearly electricity generation from PV, where the PV generation capacity begins to exceed the daytime increase of the load profile. This scenario assumes no changes of the daily constant base load generation. If the PV power is further increased to an amount of 10% of the overall electricity generation, about 8% of the PV electricity production could find no demand, starting with a surplus of PV production at noon at sunny weekends in summer time. This would reduce the nominal working hours of the PV plants by 8%, increasing the PV generation costs by the same factor. An amount of 17% of PV generation can be reached in the Zurich utility grid by storing the surplus of unused PV electricity as produced, by the widely available pumped hydro plants in the Swiss Alps. The 17% PV target would also be possible without storage, but it would require reducing the base load power production in favour of PV electricity generation. To further increase the amount of PV electricity generation above 20%, low cost storage means or changes of the load profile would be required. Copyright © 2010 John Wiley & Sons, Ltd.