6.4) Sub-Models

Determine the idea to install PV panels: Only house owners without an existing PV installation enter this submodel. They sense their local neighbourhood in a certain sensing radius and if enough of their neighbours already have a PV installed they think about installing one as well. The owners sensing radius (default of 4 patches) and the required % of PV installed in the neighbourhood to think about one (default of 10%), are both modelled as global parameters. In addition each year 0.1% of all owners without PV think about installing one independent of their neighbours.

Calculate PV investment balance and decide: PV is installed if the generation costs per kWh of electricity (depending on PV output, costs, subsidies per m2, and interest rate) are lower than the avoided costs (grid costs expected to increase) plus the feed-in tariff (subsidies per kWh expected). The generation costs are a function of the total costs for the PV installation divided by the electricity output of the panels over their lifetime. Total costs depend on the installation size, PV costs per m2, subsidies per m2, scaled by a discounting factor which is (1 + interest rate) ^ PV lifetime. This increases the total cost with increasing interest rate, which is set as a global parameter. The electricity output of the installation per year is a simple multiplication of insolation, patch-quality, PV-efficiency, roof-size, where PV-efficiency is defined as a global parameter. The avoided costs per kWh equal to the electricity costs from the grid, but since agents expect an increase in electricity price (annual growth rate), we calculate simplified mean grid costs by taking the average of a start and an end value.