Residential PV versus Ground Mounted PV - Comparing the cost of produced electricity

Abstract: The electricity produced from photovoltaics represents only a small fraction of the total electricity consumption in Sweden, but the installed capacity in Sweden doubled for the fourth year in a row in 2014. If this trend continues it is both interesting and important to discuss where we want to see PV systems in our future society. Looking at the market share of different types of PV systems in other European countries there are great variations from one country to another, and it is obvious that integrating PV in the electricity mix can be done in several ways. The same PV module can be placed on a roof top or on the ground, but might experience different conditions for producing electricity depending on tilt, azimuth angle and shading of the PV modules. Depending on where a PV system is installed it is also affected in different ways by capital subsidies, tax reductions and feed-in tariffs. By removing these aspects from an economic analysis the performance and cost can be compared between different systems, before other economic systems evens out the difference. Two types of PV systems have been compared in this study; residential PV systems versus ground mounted PV systems. The objective of the study was to calculate a comparative cost of electricity for these two different ways of installing PV and at the same time briefly address the potential environmental impacts from the space required for solar parks. The energy output was simulated with the program System Advisor Model. The azimuth angles and tilts of an average residential PV system were based on classifications used in the solar map of Lund. Two land alternatives were studied, forest and agricultural land, both covering large areas in Sweden. To include variations in cost of land and solar irradiation the simulations and calculations were performed for three different parts of Sweden; the southern, central and northern part. The conclusion from this study is that PV systems should be placed on the ground to produce the most electricity per invested Swedish crown. Agricultural land is the least expensive land type option when compared with forest, since the ground is already flat and no shading forest edge has to be taken into consideration. The irradiation has a larger impact on the cost per produced kWh than the cost of land, making PV in the far north more expensive. The environmental impact from installing PV on the ground is not well known but an installation will result in land use – and land cover change to some extent.