Welcome to f97.be!

It seemed like a good idea at the time.

Our photovoltaic installation

In July 2021 we installed a solar power system consisting of 24 x 370 Wp = 8,880 kWp and an Fronius Symo series power inverter with 7 kWp. Thanks to the optimal location and near optimal roof angle of the house - 160° south and 45° respectively - the installation is able to produce almost 60 kWh on sunny days.


Since its commissioning on 8 July 2021, the installation has produced a total of 22,69 MWh as of 1 October 2023. Our household consumption was 11,49 MWh and our cars needed 6,55 MWh.

The following diagram visualises production, consumption and - see below - the reserve built up in the grid.

Overview Overview

Here in Wallonia we have what is called the prosumer (producing consumer) tariff. By paying an annual fee (roughly kWp of the inverter / 10, so in our case about €700 p.a.), we can use the grid as an energy storage, i.e. our old electromechanical electricity meter rolls back. Energy generated in the summer can thus be taken from the grid in the winter. Unfortunately, this tariff will be abolished in 2030, but until then it is a good alternative to an expensive battery. Usually sometime in April during the time of the annual meter reading the inserted amount of energy is reset to zero, unfortunately it is not possible to carry over any balance into the following billing period.

The following diagram shows the monthly changes of our electricity meter reading.


In the first billing period from 27 July 2021 to 2 April 2022, we needed to draw an additional 322 kWh from the grid.


The second billing period from 2 April 2022 to 18 April 2023 looked better, we delivered a surplus of 2774 kWh to the grid.


A monthly overview of production and consumption can be found on the statistics page.