In Britain’s energy market, suppliers compete on price and service to win customers. In setting their prices, suppliers will seek to cover their costs and to make a profit. They face pressure to keep their prices and costs down, or else risk losing customers to their rivals.
With the exception of updating the price cap protecting prepayment customers (effective from April 2017), Ofgem does not have a role in setting energy prices, nor do we regulate suppliers’ profits. We cannot predict what prices companies will set and when prices will change – these are decisions taken by the suppliers themselves.
We do have a role to provide impartial and authoritative data about the energy market. As part of this, we publish information about the prices that households pay for their energy, the profits suppliers make and the trends in the industry costs that suppliers face. This helps to improve transparency around trends in prices, and what may be driving them.
We are also working to facilitate a more competitive, dynamic energy market, with more engaged consumers. Over time, we expect the changes we make to the retail markets to increase the competitive pressure that suppliers face, and so help to keep energy prices down.
In the charts below you can view recent trends in prices for domestic customers split by tariff type and payment method, and trends in suppliers’ domestic pre-tax profit margins. Select the 'more information' tab in the chart for a summary of the latest trends and details of the methodology used.
You can find further information on trends in prices and profits in our reports on the retail and wholesale energy markets, and on our page Understanding the profits of the large energy suppliers.
To provide insight into the most recent developments in the costs suppliers face, we publish a Supplier Cost Index.
The index tracks ongoing trends in wholesale costs, network costs and the charges to suppliers associated with government programmes that are designed to, for example, help deliver low carbon electricity and energy efficient homes, and provide direct financial support to the fuel poor.
Note that while the index gives insight into current and future cost pressures, it is neither able nor intended to predict what prices suppliers will set or when these will change. The costs that individual suppliers incur in supplying their customers may vary significantly from the index. For example, while the index reflects the level of wholesale prices in the month prior to the update, some companies may buy energy for their customers over an extended period of time to smooth their costs.
Information on suppliers’ realised costs is available in the financial statements published by the six large energy suppliers. See Understanding the profits of the large energy suppliers.
Supplier Cost Index
Select a chart for our estimates of the latest trends in the cost index, and what is behind these.
Summary: November 2017
- The Supplier Cost Index (dual fuel) increased by 6.8% between 01 August and 01 November 2017. In the previous quarter it was broadly flat. In this quarter there was a decrease in wholesale electricity costs, offset by an increase in wholesale gas costs and the costs of government obligations related to supplying electricity.
- The index in November 2017 is now 1.1% below its level in November 2016. There was a steep increase in the index in the last quarter of 2016, driven primarily by sharp movements in wholesale prices followed by a substantial decline in the first half of 2017 prior to the recent more gradual increase.
- The decrease in the index compared to November 2016 is largely a result of a decrease in wholesale electricity prices and a slight decrease in electricity network costs, offset by an increase in gas prices and the cost of government obligations related to supplying electricity (particularly programmes associated with supporting renewable and low-carbon electricity generation).
- The current index starts in January 2015. Costs fell during 2015 and early 2016, with much larger reductions for gas than electricity. After the recent increases, the dual fuel index is now 3% above its level at the start of 2015. The electricity index is 13% higher, while the gas index is 6.2% lower.
- Movements in wholesale prices have been a significant driver of the index in each period since the start in 2015. The value of the Supplier Cost Index as of November is based on average wholesale prices in October 2017 for delivery in the following 12 months. It is common among the large suppliers to purchase energy for customers on their ‘standard variable’ tariffs over an extended period (up to two years or more). This can create a lag between the latest movements in wholesale prices (as shown by the index) and the costs suppliers incur for these customers. The extent of the lag will vary depending on different suppliers’ approaches to purchasing energy.
- Across the entire period from January 2015 to November 2017 wholesale prices have fluctuated both up and down, meaning that their overall impact has been a slight increase for electricity wholesale prices, and a decrease for gas wholesale prices. Increases in the cost of government obligations related to supplying electricity account for the fact that the dual fuel index is slightly higher in November 2017 than the start of the period.
- Note that the direct costs to suppliers in relation to government programmes that are captured in the Supplier Cost Index reflect only part of their impact on suppliers’ costs and consumer bills. For example, the Energy Company Obligation supports the installation of energy efficiency measures, which are expected to reduce energy consumption and so lower bills. Because the index is calculated for a fixed level of consumption, it does not reflect this effect.
- There are likely to be some additional upwards pressures on costs in the remainder of 2017 and into 2018. From October, suppliers have been required to make capacity market payments to help ensure that there is sufficient generation capacity in the winter. The costs associated with supporting renewable and low-carbon electricity generation are also expected to rise further.
- We calculate the Supplier Cost Index by estimating trends in network charges, wholesale prices and the charges to suppliers associated with government programmes (note that in some cases, these government charges only apply to large and medium-sized suppliers).
- These estimates are then combined with information on the relative scale of each of these categories of cost to calculate the trend in the overall Supplier Cost Index. The weights given to each category of costs are based on the most recent financial statements (2016) from the six large suppliers, and are as follows:
- wholesale electricity: 26.7%
- wholesale gas: 35.9%
- networks electricity: 15.4%
- networks gas: 14.4%
- government obligations electricity: 6.7%
- government obligations gas: 1.0%.
- The index reflects estimated expected annual costs, covering the 12 months from the time of each update, based on the best information available at the time. So, for example, the value of the index for January 2017 will reflect estimated costs for the period 1 January 2017 to 31 December 2017, expressed relative to estimated expected annual costs as of the base period (1 January 2015 to 31 December 2015).
- As the estimates are forward-looking, they therefore rely on forecasts and assumptions, and so will be subject to uncertainty. Information on suppliers’ realised costs is available in the financial statements published by the six large energy suppliers. See Understanding the profits of the large energy suppliers.
- The index does not include suppliers' ‘back-office’ operating costs (such as the costs of billing or metering – including the costs of the smart meter rollout) or their profit margins, which suppliers will seek to cover when setting their prices. We are working to facilitate a more competitive, dynamic energy market, with more engaged consumers. Over time, we expect the changes we make to put more pressure on suppliers to keep such back-office costs down.
- The index is based on trends in the average prices of wholesale gas and electricity forward contracts in the month prior to the update. Suppliers will take different approaches to purchasing their wholesale energy, and many will buy their energy over an extended period. The index does not seek to estimate any impact this may have on a supplier’s costs.
- Other elements of costs are also likely to vary across individual suppliers. For example, suppliers may have some flexibility in how they meet their obligations under government programmes. This could mean, for example, that suppliers see different year-on-year changes in costs than indicated by the index where they have chosen to meet their obligations under the ECO scheme at the start of the delivery period (the forecasts used in the index are based on a flat delivery profile). Network charges will also vary between suppliers depending on things like the regional profile of their customer base.
- The index is calculated for a customer with typical consumption. We have held consumption fixed over time to increase comparability with trends in suppliers’ prices (which are also typically expressed for a given level of consumption). In practice, energy use will vary from one year to the next, depending on temperatures. Energy use is also subject to long-run trends, for example as a result of increasing energy efficiency. Trends in consumption will also have a significant impact on the size of customers’ bills.
- Capacity market payments for winter 2017 are now included in the index. In contrast to the methodology document published in March 2017, we have categorised these as wholesale electricity costs. We consider that this allocation best reflects the nature of these costs, although we note the close relationship that exists between the different categories. We intend to keep under review what further detail might be provided on the costs associated with different government programmes.
- Since the August 2017 update, we have included the additional costs associated with the expected exemption of Energy Intensive Industries from the costs of the Renewable Obligation scheme, following the Government’s recent announcement. The Government’s decision on implementing the same exemption for the Feed-in Tariff scheme has yet to be published, and so the possible impact of a similar change to the way this programme is funded is not currently included.
Further details of how we calculate the index are provided in our methodology document.
We are always looking for ways to improve our data. If you have feedback, please contact us at email@example.com.
Below you can view publications and updates relating to our monitoring of suppliers' costs, and earlier monitoring under the Supply Market Indicator.