Guidance

Smart meters statistics: methodology note

Updated 27 August 2026

1. Technical Information

1.1 Methodology

The first statistical report on the Smart Meter roll-out was published in Q2 2013 for large energy suppliers. Subsequent reports are published on a quarterly basis. Annual small supplier data was published alongside large supplier data for the first time for Q4 2015^{[footnote 1]}. Substantive changes were introduced in Q2 2026, including the addition of information on installations of smart and advanced meters replacing existing smart and advanced meters.

All energy supplier data used in these reports is received by Department for Energy Security & Net Zero one month after the end of each reporting period. It undergoes quality assurance before being combined to provide an industry-level estimate, protecting commercial sensitivity. Reports include the number of meters installed in each period, while the number of meters in operation is calculated at the end point.

We continuously work with energy suppliers to assure and improve the quality of our statistics. Sometimes, for example, after a change in reporting or management systems, energy suppliers may update past information. Where these updates are significant, these statistics will also be updated in line with DESNZ’s statistics revision policy.

Energy supplier data is cross-checked against external administrative data sources such as ElectraLink, DCC (Data Communications Company) and Xoserve. In previous years these data sources have also been used for estimating installation activity and meters in operation for suppliers who have exited the market, for example during 2021, when 23 small energy suppliers exited the market between August and December 2021.

As part of the methodology for these statistics, energy suppliers who have transitioned to large supplier classification will have their meters in operation moved into the large supplier statistics in the Q4 release. To avoid disclosing individual supplier information, their installation activity is then reported in the following quarter’s release (Q1). Table 3 lists suppliers classification transitions

Before Q1 2016, meters installed under the mandate by energy suppliers before they transitioned to large suppliers were included within the historic installation estimates for large suppliers. This ensured that reported totals installed to date by large energy suppliers were as accurate as possible. Following the introduction of small supplier statistics in Q4 2015, this was no longer needed. Historic installation totals for transitioning suppliers remain in the small supplier totals reported on at the end of the previous calendar year. 

In addition to the transition of energy suppliers to large supplier classification, it is also possible for energy suppliers to cease trading. Where this occurs, another energy supplier will inherit customers from that supplier through Ofgem’s Supplier of Last Resort scheme.

Table 3: Suppliers transitioning classifications, and large suppliers exiting the market^{[footnote 2]}

Supplier	Added to  large supplier classification	Removed from large supplier classification	Detailed information (where applicable)
Utility Warehouse	Q4 2013
Shell Energy Retail	Q1 2015		Previously known as First Utility
OVO	Q1 2015
Utilita	Q1 2016
Extra Energy	Q2 2016	Q4 2017	Transitioned to small supplier classification
Co-operative Energy	Q4 2016	Q4 2019	Bought by Octopus Energy in 2019
Economy Energy	Q4 2017	Q1 2019	Ceased trading, customers transitioned to OVO Energy
Just Energy (previously Hudson Green Star)	Q4 2017	Q4 2020 Q4 2021	Domestic business bought by Shell Energy Retail Q4 2020. Nondomestic Shell Energy UK transitioned to small supplier group
Bulb	Q1 2018	Q2 2023	Ceased trading, customers transitioned to Octopus Energy
Octopus Energy	Q4 2018
Avro Energy	Q4 2019	Q3 2021	Ceased trading, customers transitioned to Octopus Energy
Green Network Energy	Q4 2019	Q1 2021	Ceased trading, customers transitioned to EDF
Opus Energy	Q4 2019	Q1 2024	Transitioned to small supplier classification
People’s Energy	Q4 2020	Q3 2021	Ceased trading, customers transitioned to British Gas
nPower		Q4 2020	Combined reporting with E.ON, following merger in 2019
E	Q4 2021
So Energy	Q4 2021		Includes ESB
Shell Energy		Q2 2024	Ceased trading, customers transitioned to Octopus Energy
Fuse Energy	Q4 2025
Outfox Energy	Q4 2025

1.2 Energy Suppliers included in this report

13 Large Energy Suppliers:

• British Gas
• E
• E.ON Next
• EDF Energy
• Fuse Energy
• Octopus Energy
• OVO
• Outfox the Market
• Scottish Power
• So Energy
• SSE Energy Solutions
• Utilita
• Utility Warehouse

39 Small Energy suppliers at the end of 2025:

• 100Green
• Clear Business (previously Verastar)
• Brook Green Supply
• Bryt Energy
• Corona Energy
• Crown Gas & Power
• D-ENERGi
• DPG Energy (previously Delta Gas & Power)
• Dodo Energy
• Drax Energy Solutions Limited
• Dyce Energy
• Ecotricity
• ENGIE
• Evolve Energy (BPG Energy)
• Farringdon
• Opal
• Opus Energy
• Good Energy
• Home Energy
• Jellyfish Energy (previously Switch Business Gas and Power)
• Marble Power
• Maxen Power
• National Gas
• P.E Solutions (previously Pozitive Energy)
• Shell Energy Business UK
• Regent Gas
• Ruby Energy (previously BES Utilities)
• SEFE Energy
• SmartestEnergy
• SmartestEnergy Business Limited
• Square1 Energy
• Squeaky Clean Energy
• TotalEnergies Gas and Power
• Tru Energy
• Unify Energy
• United Gas & Power
• Valda Energy
• Yorkshire Gas & Power
• Yü Energy

1.3 Definitions

Term	Definition
Advanced meters	Advanced meters must, at minimum, be able to store half-hourly electricity and hourly gas data, to which the non-domestic customer has timely access and the supplier has remote access.
Domestic properties	Properties where the customer is supplied with electricity or gas, wholly or mainly for domestic purposes
Large energy suppliers	From 2022, energy suppliers who have at least 150,000 gas and/or electricity customers irrespective of whether they are domestic or non-domestic customers are classified as ‘large’ energy suppliers. They are required to report data on a calendar quarter basis. Pre-2022, supplying either gas or electricity to at least 250,000 domestic customer accounts. Note, up to Q3 2019, large suppliers were defined by domestic customers only.
New Install	When a smart or advanced meter is installed either replacing a non-smart meter or at a new connection.
Non-smart meters	All meters which are not smart (or advanced for non-domestic) meters.
Replacement	When a smart or advanced meter is installed replacing an existing smart or advanced meter.
Small energy suppliers	From 2022, energy suppliers who have less than 150,000 gas and/or electricity customers irrespective of whether they are domestic or non-domestic customers are classified as ‘large’ energy suppliers. They are required to report data on a calendar year basis. Pre-2022, supplying either gas or electricity to less than 250,000 domestic customer accounts. Note, up to Q3 2019, large suppliers were defined by domestic customers only.
Smaller non-domestic sites	Business or public sector customers whose sites use low to medium amounts of electricity (Balancing and Settlement Code Profile Classes 1, 2, 3 or 4) or gas (using less than 732MWh of gas per annum)
Smart meter	Compliant with the Smart Meter Equipment Technical Specification (SMETS1 and SMETS2) and has functionality such as being able to transmit meter readings to energy suppliers and receive data remotely
Smart meters operating in traditional mode	When a smart meter loses smart functionality and needs to be read manually it is in “traditional mode”. This can also temporarily happen for other reasons including customers switching to suppliers currently unable to operate the meter in smart mode, meters being unable to communicate via the wide area network at the point of reporting, installed meters yet to be commissioned (e.g., in new build premises).

1. Prior to this, data received from many of the small suppliers did not meet the quality standards required for publication. ↩

2. In addition to market exits, definition changes to the large supplier classification were made in the Smart Meters Targets Framework at the beginning of 2022 (see Definitions). This meant E. and So Energy transitioned into large energy suppliers. ↩