The 6 kWp photovoltaic system consists of a Fronius Symo Hybrid 5.0 hybrid inverter and a BYD Battery-Box Premium HVM 8.3 battery storage system. A Fronius Smart Meter is also installed, which in combination with Fronius Solar.web provides a clear display of the self-consumption of electricity.
The photovoltaic system has been installed on a step-by-step basis. Initially, the system was started up with a hybrid inverter, followed by the installation of the battery. A switchover box will also be activated, which is necessary for grid switching in the case that backup power is needed. This will also permit the use of three-phase loads, such as the electric oven, in the event of a power failure.
Even today, the family can store excess energy in the battery and use it when the sun is not shining.
Before the battery was installed, the owners achieved a self-consumption rate of approx. 30 %. It was possible to double this value with the storage system. Today, the family uses 60 % of the solar energy they produce themselves for their own devices, such as household appliances, lighting and the heat pump.
But it is not only the rate of self-consumption that has improved significantly with the battery; the degree of self-sufficiency has also risen from around 50 % to over 70 % (in summer), meaning that the family is already close to being independent of the public grid from May to September.
What is the effect of installing the battery in the photovoltaic system?
Increased self-consumption rate from 30 % to 60 %
|Increased degree of self-sufficiency from 50 % to 70 % (in summer)|
The BYD Battery-Box Premium HVM is modular by design. It can therefore be extended with additional modules to increase the storage capacity if required. “At the moment, we are not yet able to get through the whole night with the storage system,” says system owner Oliver Stutz. “I am already in talks with my installer to add further modules.”
The battery can be expanded in 2.8 kWh steps to up to 22.1 kWh.
“We chose our electrical appliances, such as the dishwasher and washing machine, very carefully,” reports Oliver Stutz. “All household appliances are equipped with smart technology and I can operate them remotely. For example, I switch on the dishwasher from the office when I spot that the clouds have gone away and the sun is shining.”
Fronius Solar.web provides useful services for the optimisation of electricity usage behaviour. Based on the load curves, it is easy to analyse potential improvements. Installers can therefore provide proactive customer support and give their customers competent advice.
The largest load in the Stutz household is the heat pump, which is also operated with solar power. The combination of heat pump and photovoltaics with a storage system is ideal: the storage of excess electricity and its use for operating the heat pump maximises the rate of self-consumption. Furthermore, Oliver Stutz saves energy costs because he does not have to purchase the electricity for the heat pump. A secondary Smart Meter could be integrated in order to precisely analyse the load curves of the heat pump.
A summary of the key information:
|Size of installation
|System type||Roof-top installation|
Fronius Symo Hybrid 5.0
Fronius Smart Meter
Battery-Box Premium HVM 8.3
|Self-sufficiency rate||70 %
pump, household appliances, lighting