Savings Terms and Assumptions
How we calculate the savings shown on this website
We want to be clear about how the savings figures used on the Community Energy Scheme website are calculated.
The figures on this page are illustrative examples based on an average CES customer in Stoke-on-Trent. They are not guaranteed. Your actual savings may be higher or lower depending on your electricity use, the amount of solar electricity generated at your home, the equipment installed and energy prices.
Savings at a glance
|
Customer and system |
Illustrative annual saving |
What this means |
|
Existing CES customer with solar panels only |
£148.58 a year on average |
Based on an existing CES home with energy-saving LED bulbs and a 2.55 kWp solar-panel system. |
|
Existing CES solar customer adding a battery |
Up to £437.16 a year in total |
An additional saving of up to £288.58 a year compared with the solar-only example. This includes £240 of free electricity. |
|
New customer receiving solar panels and a battery |
Up to £437.16 a year |
Based on energy-saving LED bulbs, a 3.64 kWp solar-panel system and a 20 kWh battery. This includes £240 of free electricity. |
On the homepage, these figures are presented in a simpler form:
- Solar-only customers currently save an average of £149 a year.
- Adding a battery could provide up to £288 more each year.
- New solar-and-battery customers could save up to £437 a year.
- Battery customers could receive up to £240 of free electricity each year.
The purpose of showing the solar-only figure is to give existing customers a clear starting point and demonstrate the potential increase in savings available from adding a battery. This reflects the intention agreed in the website discussion.
Assumptions used
The current savings examples are based on the following:
Standing charges are not included in the savings calculations. Customers will continue to pay the standing charge applied by their usual electricity supplier.
|
Assumption |
Figure used |
|
Location |
Stoke-on-Trent |
|
Annual household electricity use |
3,100 kWh |
|
Ofgem price-cap region |
Midlands |
|
Ofgem electricity price-cap rate |
25.33p per kWh |
|
CES solar electricity rate |
16.88p per kWh |
|
Discount against the Ofgem price cap |
33.33% |
|
Existing solar-only system |
2.55 kWp |
|
New solar-and-battery system |
3.64 kWp |
|
Battery capacity |
20 kWh |
|
Free electricity for battery customers |
£240 per year |
|
Price-cap period used |
July 2026 |
How the calculation works
The example first estimates what 3,100 kWh of electricity would cost at the Ofgem Midlands price-cap rate of 25.33p per kWh.
This is then compared with the estimated cost after taking account of:
- electricity generated by the solar panels;
- how much solar and battery electricity is used in the home;
- CES solar electricity charged at 16.88p per kWh;
- the £240 annual free electricity allowance available with the battery scheme;
- the type and size of the equipment installed.
The difference between the two estimated costs produces the illustrative annual saving.
Existing solar-panel customers
An average existing Stoke-on-Trent CES customer using 3,100 kWh of electricity a year could currently save approximately £148.58 a year with energy-saving LED bulbs and a 2.55 kWp solar-panel system.
Adding a 20 kWh battery could increase the illustrative total saving to £437.16 a year.
This represents an additional saving of up to £288.58 a year, of which £240 is provided as free electricity.
New solar-and-battery customers
An average new CES customer using 3,100 kWh of electricity a year could save up to £437.16 a year with:
- energy-saving LED bulbs;
- a 3.64 kWp solar-panel system;
- a 20 kWh battery;
- up to £240 of free electricity each year.
Installation is subject to the property being suitable and the customer being eligible for the scheme.
Why your actual savings may be different
The figures shown are examples rather than guaranteed amounts. Actual savings may vary depending on:
- how much electricity your household uses;
- when you use electricity during the day;
- how much solar electricity your system generates;
- how much solar and battery electricity you use in your home;
- the size, position and performance of the solar-panel system;
- weather conditions and shading;
- your usual electricity tariff;
- changes to the Ofgem price cap and other energy prices.
Using more or less than 3,100 kWh a year will not necessarily change savings by a fixed amount. It will also depend on how much of your electricity can be supplied by the solar panels and battery.
Draft Illustrative Savings Table
|
Annual electricity use |
Existing solar-only saving |
Total saving after adding a battery |
Additional battery saving |
New solar-and-battery saving |
|
2,000 kWh |
£95.86 |
£367.20 |
£271.34 |
£367.20 |
|
2,500 kWh |
£119.82 |
£399.00 |
£279.18 |
£399.00 |
|
3,100 kWh |
£148.58 |
£437.16 |
£288.58 |
£437.16 |
|
4,000 kWh |
£191.72 |
£494.40 |
£302.68 |
£494.40 |
|
5,000 kWh |
£239.65 |
£558.00 |
£318.35 |
£558.00 |
These are illustrative examples based on average CES system assumptions. The battery figures include £240 of free electricity each year. Your actual savings will depend on your electricity use, solar generation, system installed and energy prices.
Understanding the terminology
kWh – kilowatt hour
A unit used to measure the amount of electricity used, generated or stored.
kWp – kilowatt peak
The maximum output rating of a solar-panel system under standard test conditions.
BESS – battery energy storage system
The battery installed at the property to store electricity so it can be used later.
Ofgem price cap
A limit set by Ofgem on the amount suppliers can charge customers on certain standard variable tariffs. The rate varies by region and changes periodically.
When will these figures be updated?
The savings figures will be reviewed whenever the Ofgem price cap changes, normally every three months.
The website, homepage claims and this page should all be updated at the same time so that the figures remain consistent.
Figures last reviewed: July 2026
Price-cap rate used: 25.33p per kWh, Midlands region