Self-consumption – reasons why a solar power storage system is beneficial

With a solar power storage system, you can boost the self-consumption rate of your solar power. This pays off.

As the name suggests, the definition of self-consumption is that you use the electricity generated by your photovoltaic system yourself. In the simplest scenario: the sun is shining, and you have loaded your washing machine, which will be powered by simultaneously generated electricity.  This will, of course, not work on a rainy day or at nighttime. Here is where solar power storage units come into the picture. They will store your electricity for use at a later time. It has been calculated that a combination of a solar system and solar power storage can raise the self-consumption rate to between 50 to 80 per cent.

You also save money as self-generated electricity is almost always cheaper than purchased electricity. Depending on the supplier and the photovoltaic system, the price difference can be up to 20 cents per kilowatt hour (data for Germany in 2020)

Benefits of higher self-consumption

1. Lower electricity costs

Self-generated electricity is cheaper than the electricity bought from an energy provider. Currently in Germany, the feed-in tariff in for a PV system with less than 10 kWp is just under 10 cents per kilowatt hour. The average price for household consumer electricity, in contrast, is over 30 cents per kilowatt hour. Your savings are more than 20 cents per kilowatt hour. Every kilowatt hour of self-consumption increases the profitability of the photovoltaic system. The higher your rate of self-consumption is, the faster the investment in the photovoltaic system and the power storage unit will pay off.

A PV system generates the bulk of its solar power around the midday hours. The morning and evening hours, however, are usually responsible for the highest household electricity consumption. It makes sense to temporarily store the generated electricity. Using a solar power storage unit creates the prerequisite to increase your self-consumption rate of self-generated solar energy. You will thus obtain your electricity much more cheaply.

2. Contribution to the energy transition

Your solar power derives from a 100% renewable energy source. That is certain. Local grid operators often provide electricity from a mix of different energy sources - of which usually only 50% come from renewables.  Many utilities are thus pursuing a twin-track strategy; in addition to electricity from renewable energies, they also sell nuclear and coal-fired power which does not contribute to the energy transition.

3. Grid stability

During extended periods of sunshine too much electricity is generated by PV systems at the same time. Every photovoltaic system operator then feeds the electricity into the public grid, which is increasingly becoming problematic for grid stability. Since there is insufficient storage capacity, the grid is quickly overloaded. When you optimise the self-consumption rate, you contribute to improved grid stability. You consume the decentrally generated electricity directly and thus relieve the load on the power grid.

How to increase self-consumption

There are several options to increase the self-consumption rate of your photovoltaic system. The most efficient one is adding a solar power storage system. It will offer you the best flexibility and the added benefit to compensate grid outages.

Another approach is to combine a photovoltaic system with an electrically powered heat pump. Heat pumps usually use the excess electricity that cannot be temporarily stored in the battery. This will raise your self-consumption rate.

Owners of an electric vehicle have a third option to boost the self-consumption rate by installing a wallbox. Excess solar power that you don't need in your household can be used to charge the electric vehicle cheaply. Combining the wallbox with a solar power storage unit, allows you to optimise the charging strategy alongside domestic electricity requirements and further boost the self-consumption rate.

A fourth approach incorporates digitalised appliance controls or intelligent residential energy management systems. Appliances, such as the washing machine or dishwasher, switch on when your PV system generates electricity.

Increase self-consumption with solar power storage now

A solar power storage system is a particularly efficient addition to boost the self-consumption rate of your PV system. It will provide more independence of energy suppliers and grid operators - and thus also protect against a future rise of household consumer electricity prices. The higher your self-consumption rate, the lower your total energy costs.