In short: most likely most of the time.
Your kit’s production of electricity is almost never the exact same as the consumption of your household. If you produce less than you consume, then 100% of your production is used on the spot, maximizing the economic profitability of your kit as you take full advantage of the savings.
If you produce more than you consume, you have several options:
- You can install a “zero discharge” device on your distribution panel, that lowers your kit’s production and avoids any spillover of excess electricity to the power grid
- You can feed the excess energy to the power grid (for free or by getting paid)
- You can add a battery to your kit, and store the excess energy during sunshine hours, to use it when the sun doesn't shine.
A zero discharge device doesn’t make a lot of sense in practical terms, as your surplus energy will be low or non-existent. And yet, your local regulation might require you to install it. Also, we have heard of power companies that (absurdly!) count excess energy as consumption and charge you for it. This is illegal and abusive behavior! Should this be the case, contact us and we will help you fight your power company to stop this practice.
Usually you can avoid installing a zero discharge device by having an electrician certify your installation. This has the added benefit that you can claim compensation for the energy you feed into the network. You might want to check the economic benefits though, as certification costs money (for the certifier and in some regions for government fees), the amount of energy you feed into the network is likely to be low, and the price per kWh you will get paid is normally much lower than the one you pay for a kWh you consume. Some power companies offer “virtual batteries”, that make you use the kWh you feed into the network at other times.
If you feed a lot of energy to the power network, you probably want to install a battery, store the excess energy, and use it when the sun doesn’t shine. Our battery systems are modular, and you can install up to 4 batteries of 1kWh each in the same system. This allows you to start small, and add batteries as you see your excess energy increase.