Self consumption of solar PV
The percentage self-consumption of solar PV is an indication of how much of the electricity produced by a domestic solar PV array that has been consumed by the household. If half of the electricity produced by the PV is consumed by the household, the percentage self-consumption is 50%.
The self-consumption is affected by various factors such as the level of solar PV generation, household consumption and times of consumption. The Microgeneration Certification Scheme (MCS) has produced a Guidance Note which allows estimates of the amount of self-consumption to be made. This is based on actual data and modelling by organisations like Loughborough University.
For domestic solar PV installations receiving the feed-in tariff, payments were based on deeming the level of export (and self-consumption) of solar PV to be 50%. In practice, the level of self-consumption is often lower than this, particularly with larger PV systems.
The figure below shows estimates of the percentage self-consumption for a household with annual electricity consumption of between 3,000 and 3,499 kWh. The percentage self-consumption decreases with increased solar PV generation and when the household spends less time at home during the day. This means a higher proportion of the electricity is being exported to the grid and the household would benefit by shifting electricity consumption to times when there is greater generation from solar PV.
![](https://www.nea.org.uk/wp-content/uploads/2020/11/self-consumption-percent.jpg)
An increase in self-consumption of the solar PV can be achieved using the following methods:
- Install domestic battery storage to store excess electricity generation for consumption later in the day.
- Install a solar immersion controller. This can use excess solar generation to power the immersion heater for a hot water cylinder. This reduces fuel bills for domestic hot water.
- Run appliances like washing machines or dishwashers in the middle of the day when solar generation is higher.
- Where safe, use a timer or smart socket to schedule a suitable appliance to run during the day. This might include charging a laptop or tablet computer.