Addition magazine energy to an existing PV installation - let's find out how!
Nowadays, more and more people are choosing to install photovoltaic (PV) panels on their roofs, enjoying the benefits of renewable energy. However, just having a PV installation is only the beginning. Energy storage, which allows the generated energy to be managed efficiently, is also becoming increasingly popular. So how do you add energy storage to an existing PV installation? Let's find out step by step!
How to extend an existing photovoltaic installation with energy storage?
If you decide to extend your current photovoltaic installation with energy storage, the most important step of this investment is to check whether your current inverter has a battery input. Prosumers who did not foresee a future expansion with energy storage at the design stage of their installation may encounter a problem. If you have an inverter without a battery input, unfortunately, it will not be compatible with the energy storage. In this situation, you have two options: purchase a new inverter or retrofit your current inverter with a so-called retrofit. A retrofit is an AC charger that adds an energy storage function to an existing photovoltaic installation.
To find out whether your inverter has a battery input, you can consult the data sheet of the device or carry out a verification. Inverters prepared for a battery system, in addition to the connectors for plugging in the photovoltaic installation, also have two inputs described as "bat" (battery). If the device does not have these inputs, it means that the inverter is not prepared for expansion with energy storage.
The current advice from experts in such cases is to replace the inverter with a hybrid model, as retrofitting the old one with a retrofit is not more cost-effective.
Connection power
Extending an existing photovoltaic installation with energy storage will require verification of the connection capacity. This is an important point, because if the capacity is insufficient, it will then be necessary to request an increase from the energy supplier.
The current legislation distinguishes between two cases where the battery power is summed up with the power of the photovoltaic installation:
- When the total power of the micro-installation is less than the storage capacity.
- When the total power of the micro-installation is greater than the power of the energy storage, but the maximum power of the inverter exceeds the power of the micro-installation.
To check and add up these values correctly, it is important to remember that storage capacity and power are two different parameters. On the data sheet, capacity is expressed in kWh, while power (which we are interested in in this case) is given in kW.
It can also happen that the power of the micro-installation is greater than the power of the storage and the maximum power of the inverter is less than the summed power of the micro-installation. In this case, the power summation principle does not apply.
Case 1: Aggregation of capacities
Let us assume that the photovoltaic installation has the following parameters:
- Power of the micro-installation: 8.9 kW
- Hybrid inverter power: 9 kW
The developer plans to add 4.56 kW of energy storage.
In this situation, the power summation condition is met because the power of the micro-installation is less than the power of the hybrid inverter and the power of the storage is greater than the power of the micro-installation. We report to the distribution network operator a minimum connection power equal to:
8.9+4.56=13.55 kW
Case 2: No summation of power
Let us consider the case where the condition of no aggregation of power is met:
- Power of the micro-installation: 8.5 kW
- Hybrid inverter power: 8 kW
The developer plans to add 7.8 kW of energy storage.
In this situation, the condition of no summation of power is met because the power of the inverter is less than the summation power of the micro-installation and the power of the energy storage is less than the power of the micro-installation. Therefore, the power to be reported to the electricity utility brings:
8.5 kW
Summary
Adding energy storage to an existing PV installation is an investment that can bring many benefits, both financially and in terms of energy comfort. The key to success is an accurate assessment of your needs, selection of the right energy storage and professional installation and configuration of the system. In this way, you will be able to enjoy the full benefits of renewable energy, while protecting yourself against possible power cuts.
