Although it initially had a chilling effect on the Polish residential solar market, the transition from net metering to net billing has also led to positive changes, such as better sizing of rooftop solar systems and higher self-consumption, says Instytut Energetyki Odnawialnej. (IEO), a Polish research institute.
According to IEO, the first effects on pro-consumers were visible in last year’s installation figures, but the effects of the change on investors and installers are still unclear. In the first quarter of 2022, approximately 1.3 GW of micro-installation solar capacity was connected. About 152,000 systems with an average power of 8.3 kW were installed in the system. This equated to around 1,700 installs per day. After switching to net billing, the amount dropped to 375 MW in the third quarter.
“The net billing system has slowed down the development of prosumer installations, but not because it is a bad solution,” the IEO said. “It was about accepting and learning the new rules by installers and consumers, and understanding banks and financial institutions.”
It also points to the positive effects of the net billing system, including better sizing of solar installations and investments in additional equipment that enables the use of additional solar energy, such as heat pumps and battery energy storage systems.
According to IEO, the new net billing system leads to a higher rate of self-consumption. It said that under the net billing system, with the support of the Mój prąd (My Electricity) rebate program, producer-consumers investing in small solar installations of 4-5kW will get a better internal rate of return (IRR) of 19%. to 25%. The net metering system offered an IRR of only 13–14 percent.
Under the old net metering rules, owners of solar systems under 10 kW were allowed to feed up to 80% of their output to the grid, while solar systems ranging in size from 10 kW to 50 kW were allowed to feed up to 70%. from their electricity to the grid. According to the new online invoicing rules, producers’ consumers must draw up an invoice that includes the energy they produce. The price is then calculated according to a special model, which is related to the price of a kilowatt hour, the so-called “day-ahead” during trading.
Almost 80 percent of the installed solar power capacity in Poland is the share of producer users. At the end of last year, the number of producer users exceeded 1.2 million and the total capacity of their facilities was over 9.3 GW. This means that the average power of the micro-installation is 7.6 kW.
The IEO’s power forecast assumes that the country’s cumulative solar capacity will be 20 GW in 2025. By 2030, this figure should be 29 GW, of which 15 GW will be from consumer sources, including 4 GW from company-owned solar systems.