Techno-Economic Analysis of Utility Scale PV Power Plants with up to +/- 1500 VDC

Today most utility scale PV power plants have a system voltage of 1000 V and converter substations with around 1 MWp power. At the moment, the first 1500 VDC photovoltaic modules are entering the market. In order to reduce the cost, it seems promising to increase the DC voltage level of the plant and the maximum power of the converter substations which decreases the total cable length and the number of converter substations in the plant. In this work the cost of different PV power plant layouts at high DC voltage levels were determined. Four different concepts were worked out, firstly a 1000 VDC (state of the art), secondly a 1500 VDC (state of the art with increased voltage), thirdly a topology for a 2-stage concept with fixed voltage link and fourthly a bipolar PV-Generator. The most significant conclusion from this study was the 30% lower Balance of system (BOS) costs and subsequent savings in Levelized Cost of Electricity achieved from the power plant concepts with higher system voltage compared to the state of the art. With continuous fall in module and inverter prices, the BOS cost cut will be of greater significance in the near future. Further an analysis of potentail savings in PV system oriented in the East West compared to regular South facing plants was made. It shows that this is not recomanded for utility scale power plants due to lower energy harvest specialy in the winter season.