What are Radio Teleswitch System meters and how many are there in Great Britain?

This is the first in a series of articles on Radio Teleswitch System (RTS) meters.

Long before smart meters, an option for variable rate meters was the Radio Teleswitch System, which relied on a radio signal for timing information. Since April 2020 the costs for the RTS service have been recovered through the Balancing and Settlement Code (BSC) charging arrangements. They were previously borne by the Energy Networks Association (ENA). The cost for the RTS service is a direct pass through to BSC Parties, and it has increased from £1.5m in 2022/23 to £4.9m in our 2023/24 business plan.

Customers benefit from cheaper tariffs at different times of the day

Radio Teleswitch System meters pick up a signal broadcast alongside the long wave signal for BBC Radio 4. England is covered by a signal transmitter at Droitwich, with smaller transmitters at Westerglen and Burghead providing signal coverage for Scotland and Northern Ireland.

The meters allow customers to benefit from cheaper tariffs at different times during the day. The system has also been used for some hot water control systems, bringing hot water tanks up to temperature during lower rate times for electricity.

The system began operating in the 1980s. The signal is capable of providing various types of update information to adjust the meters, depending on their settings.

Replacing RTS meters with smart meters

RTS meters are being steadily replaced with smart meters which use telecoms networks to send and receive data, including that for switching tariff rates.  The final deadline for the signal to be switched off is currently set for March 2024.

Without the signal, the behaviour of RTS meters are uncertain. Some may continue to switch between tariffs using internal memory settings while some may remain on whatever tariff was in place when they last received a signal.

As the RTS meters have been phased out, the current stock is aging. As such problems become more likely.

Where can I find the data?

There are currently around one million RTS meters in operation across the country.

The four suppliers with the most RTS Meters in operation account for just over half of all the remaining RTS meters. These are Scottish Power,  OVO Energy, E.ON Next Energy and Octopus Energy. For the majority of Suppliers with RTS meters, these meters represent less than 5% of their meter stock, based on Metering System Identifiers (MSIDs) which are unique identification numbers for each meter.

RTS meters tend to make up a greater proportion of meter stock in Scotland, particularly the North.

The number of RTS meters in operation is published as part of our monthly Trading Operations Report, together with a breakdown of which suppliers (by Market Participant Identifier (MPID)) own the meters.

What’s next?

Although the RTS is intended to be retired in the near future, meters relying on the signal still comprise a noticeable part of the general metering stock. In the next RTS article, two weeks from now, we will look at the distribution of RTS meters across the country and the classes of sites where they are installed.


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