Retrofitting photovoltaic system with solar power storage units

In 2020, more than 1.7 million photovoltaic systems with a combined capacity of 52.7 gigawatts are installed in Germany. They are responsible for around 12 % of the net electricity production. The bulk of these systems were installed between 2008 and 2013, a period when the Renewable Energy Sources Act [EEG] strongly promoted growth in the sector. The majority of these PV systems and those installed in the following years are not equipped with a solar power storage unit. However, if the current feed-in tariff remuneration for your PV system is about to expire, adding a solar power storage unit is a useful, worthwhile and money-saving option. 

Retrofitting an AC-coupled solar power storage 

Can existing photovoltaic systems be retrofitted with a solar power storage unit? The short and simple answer is yes, using an AC-coupled storage system.

Existing solar power systems already come with a PV inverter installed. Therefore, retrofitting with an AC-coupled solar power storage unit presents a good option for these systems. AC-coupled storage systems are easy to integrate as they work independently of the photovoltaic system. The existing PV inverter is retrofitted with an additional battery inverter. The battery unit is then connected to this battery inverter.

The battery inverter RCT Power Storage AC optimises the yields through an intelligent charging strategy and is very gentle on the battery. Programmable switching outputs ensure that excess power is not fed into the grid but can instead be targeted at a heat pump, an electric car or other consumers. The RCT Power Storage AC keeps the charging and discharging currents low due to high voltages minimising the temperature cycles in the battery. This leads to a significantly increased service life, especially with Li based battery cells of all types.

Is it worthwhile to retrofit the PV system with a solar power storage unit?

The investment in a solar power storage unit is worthwhile for most applications. It is no accident that the sales of batteries are up. In August 2018, the 100,000th home power storage unit was commissioned in Germany. Less than two years later, the number has already doubled, as the German Solar Industry Association announced in June 2020. The reasons are obvious: Solar power storage units make you independent of electricity market price fluctuations. You have to buy less electricity at expensive prices. The batteries become more powerful and cheaper. Besides, you can use your self-generated electricity regardless of weather conditions and time of day.

And last but not least: The use of an AC battery inverter also makes retrofitting cheaper. The connection of the AC-coupled storage system from RCT Power takes places via Plug & Play. Commissioning is completed via the RCT Power App.

Whether investing in retrofitting your photovoltaic system will pay off cannot be generalised. This depends on the initial time of installation of the solar modules, the amount of electricity they generate, your self-consumption and the current legal framework. In addition to the economic benefits, you should also consider benefits such as increasing independence from energy suppliers and weather conditions as well as climate protection support in your calculations.

Are you thinking about retrofitting your PV system?

Our specialist partners are happy to help  and explain the opportunities retrofitting presents in detail. Contact us.