Insight Report: Domestic Solar PV Customers
Overview
The transition to a low carbon energy network is likely to include a higher proportion of distributed renewable energy generation, in which domestic solar photovoltaic (PV) technology is likely to play an important role. As the electricity network was not designed to accommodate distributed energy generation such as PV, it is important to understand the impacts that might arise on the energy network as a result of widespread PV deployment. Households with PV installations were monitored for the Customer-Led Network Revolution project, to understand their electricity generation and consumption patterns.
This report considers two household groups or ‘test cells’ as they are referred to for CLNR: Test Cell 5 is comprised of 143 households with solar PV, and Test Cell 20IHD of an additional 149 households which in addition to solar PV had an in-home display (IHD) notifying users when electricity generation exceeded household demand and was therefore being exported to the grid. The IHD was intended as a prompt to users who could then choose to utilise this excess generation within the home which could reduce PV export at times of peak PV energy generation. These two test cells were compared against the baseline control group of domestic customers with smart meters Test Cell 1a.
When making comparisons between the test cells, in general it is only possible to state the trends observed averaged across groups of customers. It is not possible to make definitive and accurate statements about specific customers, because the distribution of behaviour tends to be quite large, even within a customer group.
Compared to TC1a (the base domestic profile and control group), households with solar PV were found to show:
- Lower net annual electricity consumption (by 32% for TC5 and 22% for TC20(IHD))
- However, excluding PV generation they showed higher gross annual electricity consumption than TC1a (between 10% and 30% greater for TC5, and 24%-43% greater for TC20 (IHD)).
- Higher peaks in demand during the 4-8pm period (when compared to TC1a, the mean of customers’ daily evening peaks, averaged across the year and across all households in the test cell was 14%-33% greater for TC5 and 24-31% greater for TC20 (IHD)).
- A greater fraction of electricity use during the 10am-4pm period(mean of 30% of daily use for TC5 and TC20 (IHD) compared to 27% for TC1a).
However, it was not possible to account for demographic factors in the comparison. Therefore it is not clear to what extent the above are a result of behaviour change arising directly from the PV installations, or PV take-up being more highly correlated with some customer groups where the above behaviour was pre-existing to some extent.
On average, the households in the solar PV test cells generated per annum an amount of electricity equivalent to just over 40% of their annual electricity consumption. While some electricity was exported, especially in the summer months around midday, around 80% of the electricity generated was used on site.
