store solar energy in home batteries for self-use

The netting arrangement will remain in place for the time being. However, using the self-generated solar power yourself is becoming increasingly attractive. But how do you use the generated energy effectively? Or how do you store that energy, so that you can use it at a later time? Despite the maintenance of the netting arrangement, returning solar energy is no longer always attractive. More and more energy suppliers are charging a return delivery fee. At peak times, it is not even possible to generate solar energy everywhere.

Imbalance costs money

Until now, the imbalance between self-generated solar energy and required electricity was always absorbed by the electricity grid. The netting scheme stimulated this self-generation and the amount of solar energy supplied to the electricity grid increased. The grid functioned as a free and bottomless home battery for owners of solar panels. Until grid congestion started to throw a spanner in the works.

Too much is not good

Inverters convert the direct current from solar panels to alternating current for mains voltage. When the mains voltage exceeds 253 volts, the inverters of PV installations automatically switch off. The mains voltage can increase when too much solar power goes to the electricity grid and there are too few power consumers at the same time. When that happens, there is grid congestion.

Self-use

This can be (partially) solved when owners of solar panels use as much of the self-generated power as possible at the time of generation. This consumption should preferably be useful. For example: turning on the oven empty uses a lot of power, but does not produce a pastry. But charging your electric car on a sunny afternoon, or running a full washing machine, is useful consumption. Unfortunately, not everyone with solar panels has an electric car, and not always a full washing machine at the right time.

Who saves what

The big 'problem' with solar energy is that it is mainly available when consumption is lowest. During the day, that is, when most people are at work or at school. During the year, that is mainly during the period of the year when it is already light for longer, and warmer as well. In the most ideal case, you would want to save the excess solar power that you generate then, until a time when there is no or less sun. For the evening and at night, when you look at it per day. Or for late autumn and winter, if you look at the entire year.

Big, bigger, biggest

Balancing the electricity consumption and the self-generated solar energy of a household per day is not such a problem technically. Especially in the summer, it is a matter of sufficient solar panels, sufficient battery capacity and some supporting technology. Anyone who is prepared to invest generously in the technology can, so to speak, go off-grid tomorrow. Only: that requires a considerable investment in batteries or home batteries. And the problem remains that in the winter the yield of PV panels often does not cover the own consumption.

Overcapacity

In order for every household to provide for its energy consumption on winter days with its own PV panels and home batteries, every household would need a large excess of PV panels. These solar panels would then generate far too much energy in the summer. Not a practical option, therefore. Moreover, from a sustainability perspective, it is also completely undesirable.

Limited shelf life

Home batteries have another major disadvantage, besides their still high cost (currently around 750 euros per kWh). They are relatively limited in capacity. According to Milieucentraal, an average household consumed around 6.85 kWh of electricity per day in 2023 (2,500 kWh/365 days). This means that this family can only last an average of less than two days with a 10 kWh home battery. Moreover, this average consumption does not include the amount of natural gas that the average household burned. In order to heat a home all-electrically, the electrical consumption of a heat pump must therefore also be included instead of the gas consumption. Even without a heat pump, the home battery will have a hard time in this example. Energy consumption is higher in winter than in summer, while less solar energy comes from the PV panels in winter.