Net-Metering vs. Net-Billing from the Investors Perspective—Impacts of Changes in RES Financing in Poland on the Profitability of a Joint Photovoltaic Panels and Heat Pump System

The paper explores the impacts of changes in renewable energy sources (RES) financing in Poland on the profitability of coupled photovoltaic panels and heat pump systems. The profitability analysis is conducted with the use of Net Present Value calculation and the return on investment period. The degree of change in profitability of using photovoltaic panels in Poland is dependent on the method of their financing. The analysis is carried out for two different photovoltaic support schemes: (1) the net-metering scheme currently in force in Poland; (2) the net-billing system scheduled for implementation in the year 2022. It is assumed for the analysis that two alternative heating and electricity supply systems for a single-family building will be operated: (a) a standard solution used in Poland consisting of a natural gas-fired boiler for heating and the purchase of electricity from the power grid, (b) an air/water heat pump used to heat the building, and electricity obtained from photovoltaic panels, also used to power the heat pump. A sensitivity analysis is carried out, examining the impact of several key parameters relevant for the profitability of such investments, such as average annual increase in the purchasing or selling prices of electricity, purchasing prices of natural gas, and inflation rate. The conclusions concern the possible consequences of introducing a new support scheme for photovoltaics in Poland. The highest profitability of all considered solutions is for the current scenario for heat pump and pv installation with the capacity to meet the demand in the last year of operation. The introduction of changes in the new RES law (2021) in Poland will reduce the profitability of investments in pv panels, leading to a slowdown in the investments in the pv installations.