More and more builders of apartment buildings are planning to include photovoltaics right from the start. But they often face the question of what to do with the electricity supplied by the solar modules in the facade or the roof. In apartment buildings in particular, using the electricity on site is one way of refinancing the solar system through the costs saved on grid electricity. This is because the load profiles here are flatter than in a single-family home, where most of the electricity is consumed in the morning and evening hours. In apartment buildings, electricity use is better distributed over the entire day, even though most of the load still occurs when the residents come home from work or before they go to work.
Consuming a lot of electricity on site
A tenant electricity project is successful when as much electricity as possible is consumed locally. This is because self-generated solar electricity has long since become cheaper than electricity from the grid. The way to boost consumption on site is therefore via power consumers that run when the residents of the apartment building are out and about. The prerequisite is that these additional power consumers are devices that would consume energy anyway. In addition to heat pumps and electric heaters, electric cars are a good option here. "How strong the influence of charging stations on direct consumption is depends on the number of charging stations and the electric cars of the residents as well as their charging times," explains Florian Henle, Managing Director of the green energy supplier Polarstrom.
See also:
Floating solar housing estate
The company specialises in the implementation of tenant electricity projects. If the charging stations are installed in the buildings and supplied with solar power, this should be done primarily in new buildings or during renovation. Because then the required grid connection capacity can be planned at the same time. After all, electric cars do not usually charge exclusively with solar power.
Implement load management
Polarstrom advises the installation of a load management system in addition. This is the only way to guarantee a fair supply of electricity to the residents and the charging stations with the solar power generated. Typically, the households are first supplied with solar power. Only when the solar modules generate more electricity than they consume can this surplus flow into the batteries of the electric cars.
Using electric cars to store electricity
The attractiveness of charging stations in tenant electricity also increases if bidirectional charging is possible. Then the electric cars of the residents can be used as storage. This is because the batteries of the electric cars can then temporarily store the excess electricity from the building's solar system and feed it back into the household grid as needed. This would support the residents' electricity self-sufficiency and further reduce electricity costs, Polarstrom emphasises. (su/mfo)
