According to a recent joint research report by the European Photovoltaic Industry Association (SPE) and Energy Brainpool, high capital expenditures and interest rates have extended the average investment payback time for photovoltaic systems installed in some EU member countries, namely Germany, Spain, and Italy, to around 20 years in 2022. The study also analyzed the symbiotic effect of rooftop photovoltaic systems and heat pumps.

The research report considers various scenarios, including the "New Normal," where natural gas prices remain at current levels; "fossil fuel dumping," where global natural gas demand has significantly decreased, leading to a decrease in fossil fuel prices, and the "return to crisis," where natural gas prices rose to their high levels in the autumn of 2021. The report indicates that the average installed capacity of rooftop photovoltaic systems installed in Germany in 2022 is 8kW, while in Spain and Italy it is 7kW.

Under the "New Normal" scenario, the return on investment for rooftop photovoltaic systems installed in Germany is about 18 years, Spain is 19 years, and Italy is 14 years. In the scenario of "fossil fuel dumping," the investment payback time is 20 years, 25 years, and 17 years, respectively. In the scenario of the "return to crisis," the investment payback time for rooftop photovoltaic systems is the lowest, with 17 years in Germany, 12 years in Italy, and 11 years in Spain.

Christophe Lits, market analyst at the European Photovoltaic Industry Association (SPE), said that the investment payback period of rooftop photovoltaic systems is often believed to be less than 10 years. However, this model considers all factors as of 2022, including capital expenditure price, electricity price, interest rate, grid electricity price, tax refund plan, etc. Liets noted that high capital expenditures, low electricity prices in the years after 2022, and high interest rates for using loans to purchase photovoltaic systems are the main factors that lead to an increase in the investment payback time of rooftop photovoltaic systems installed in these three countries in 2022.

The report concludes that capital expenditure support is crucial for shortening the investment payback time in an environment of high interest rates and high labor costs. It proposes that EU member states can provide capital expenditure support, which can shorten the investment payback time of photovoltaic systems and heat pumps in Germany, Italy, and Spain by 6 to 8 years. The report also conducted sensitivity analysis on investment payback times for different capital expenditure values.

In conclusion, this research report provides insights into the investment payback time for rooftop photovoltaic systems in EU member countries and highlights the importance of capital expenditure support to reduce the payback period