Technical Information

Types of Smart Meter

There are two main types of smart meters – the older models known as SMETS 1 (Smart Meter Equipment Technical Specifications) and the newer versions that were rolled out in 2018, known as SMETS 2.

• SMETS 1 – Most of these communicate with your supplier through the 3G mobile network. Unfortunately a number of different systems, not linked together, are used to manage these meters and so if you change suppliers it is likely that your new supplier will not be able to operate your Smart Meter and it will become a ‘dumb’ meter for operational purposes.
• SMETS 2 – This specification is more advanced and meters were first rolled out in 2018. A purpose built communication network is used with these meters and all suppliers will use it this – making switching easier and keeping your smart meter smart.

Roll-out Progress

The good people at Elexon (they manage electricity industry data) are now reporting SMETS1 and SMETS2 meter installation data every month. Although this is for electricity only it gives a good indication of overall progress.

In December 2019 the SMETS2 installs were 159k, down from 201k in November. The SMETS1 installs dropped slightly to 23k from 29k in November. So the odds of you getting a SMETS2 meter have worsened to 61% from 77% in November. However this is to be expected in December when installs always fall to their lowest level. We would like to see that get to 85% before we recommend people say Yes to a Smart Meter.

We would suggest that you continue to say no to a smart meter, as there is still a good chance you would end up with the older model which is less secure and has less features.

Here is a link to Elexon’s report: https://www.elexon.co.uk/about/key-data-reports/smart-meter-technical-detail-report/.

Wide Area Network

The Wide Area Network or WAN is the name given to the communications network between the meters and the company responsible for collecting the data and passing it on to other businesses such as suppliers. This company will usually be the DCC (Data Communications Company) which the government has set up especially for this role supporting the final SMETS2 meters. Depending on the Communications Service Provider, which varies by areas of the UK, the technology can change depending on what works best in a local area. Sometimes your meter will communicate directly with DCC and sometimes it will talk through the meters around you to reach a particular meter which has direct communications with DCC. This form of communications looks like a mesh when you draw out the possible links between meters and is therefore known as a Mesh network.

Home Area Network

The Home Area Network or HAN is a bit like your home broadband wireless network and will be used to communicate between the meters, the In Home Display and other items as and when they become available. The communication protocol chosen for Smart Meters is Zigbee as it is simple, inexpensive, low power and secure. The range of this technology is about 15m, but this is reduced by obstructions such as walls and doors.

Normally the Communications Hub that manages the HAN sits on top of your electricity meter and communicates with the electricity meter, gas meter and In Home Display. The range of the Smart Meter HAN is about 15m, but this is reduced by obstructions such as walls and doors.

Where the meter is a long way from the location of the In Home Display, or thick walls are in the way, the current technology (Zigbee at 2.4GHz) won't work. This could be the case for up to 30% of properties.

A different communications method (Zigbee 868MHz) available from mid 2020 will improve this for about 3.5% of properties but that still leaves a large number for whom Smart Meters won't work.

For these final properties, for example where meters are in a basement a long way from the customer's IHD, a separate company has been set up to investigate solutions, prepare contracts and procure the equipment. The company is the Alt HAN Co Ltd and solutions are expected in 2021.

HAN Solutions

1. Standard HAN 2.4GHz
• Normal small and medium houses
• Nominal range of 15m
• 70% of premises
2. Dual Band HAN 868MHz
• Large houses and buildings, thick walls
• Signal can travel further but is lower bandwidth and therefore slower
• 25% of premises
• Available mid 2020
• More expensive than Standard, additional £24.20 per meter set
3. Alternative HAN solutions
• Long distance between meters and IHD, for flats with meters in a basement
• Between 2% and 3.5% of premises
• Most expensive solution
• New company Alt HAN Co Ltd formed to manage this
• Solutions being tested:
  • Power Line Carrier (PLC) device
  • Leaky Feeder Aerials
  • Larger aerials on comms hub
• Installed from 2021 onwards
• Total additional cost £290M
4. No solution (too costly)
• Extreme distances
• Faraday cage buildings
• Between 1.5% and 3% of premises.

Meter Alerts

Smart Meters can send information about the meter's environment and status as well as meter readings. This information can be used to diagnose meter faults, detect theft and security issues. There are some 250 events which can be sent in this way, suppliers and distributors will monitor these alerts, and take action at the appropriate point. For example a memory alert may mean the meter is faulty, whereas a reverse flow alert could mean that someone has reversed the meter in order steal energy.

Security

Security has been considered very carefully for Smart Meters. The communications network is not part of the internet, it is a closed network only accessible to parties with the right security keys and physical connections. Additionally there is no central database containing customers' information, the information is only stored on the Smart Meters and sent through DCC onto Suppliers and other parties who have a right to that data and where the customer has given them permission. The customer information inside messages is encrypted and only the receiving party can look at the data, the DCC cannot view the data. The parties receiving the data undergo a rigorous security assessment at the beginning and then have regular security audits.

The National Cyber Security Centre has an excellent document explaining how the security works in relatively simple English.

PAYG

The ability to purchase electricity and gas on a PAYG (Pay As You Go) basis is a big advantage of Smart Meters. Once you've paid, top up can be sent to your meter automatically without having to use chargeable key fobs. If communication to the meter is down you can still top up by entering the long reference number provided with your purchase into the meter, although this may not be an easy thing to do. For customers on PAYG who have difficulty with reliable communications and entering the long number, a separate number entry pad can be provided by your supplier. However it should be noted that many suppliers didn't start to offer the PAYG service until late 2018.

Distribution Network

As well as Suppliers getting information from smart meters the Distribution Network Operators (DNOs), who look after the cables in the ground, will also get information. They can use this information to detect when cables might get too hot, the voltage drops in an area (known as a brownout) and when the power cuts out. The detailed information of performance over time can be used to help plan reinforcement of the network as demand increases.

Meters

Both SMETS1 and SMETS2 meters are being installed currently. If you are wondering if you have a SMETS2 meter, look up your meter model number in the table below which lists all currently approved SMETS2 meters.

ESME = Electricity Smart Metering Equipment
GSME = Gas Smart Metering Equipment
ALCS = Auxiliary Load Control Switch.

Diaphragm type gas meters have been used for many years. Within the meter there are two or more chambers formed by movable diaphragms. With the gas flow directed by internal valves, the chambers alternately fill and expel gas, producing a nearly continuous flow through the meter. As the diaphragms expand and contract, levers connected to cranks can link to a counter or provide an electrical pulse to measure the gas volume.

Ultrasonic gas meters measure very small difference in time that it takes an ultrasonic pulse to travel with and against the flowing gas stream. A microprocessor can then calculate the gas used. The main advantages of ultrasonic gas meters are that they have no moving parts and are therefore more reliable, and they are more accurate than conventional gas meters.

Existing SMETS1 meters in the table below will be migrated to the new DCC SMETS2 system through the enrolment and adoption process. If you are wondering if you have one of these SMETS1 meters, look up your meter model number in the table below.

• Initial Operating Capability (IOC) – meters operated by CGI Instant Energy (IE)
  • 24 Nov 2019 - Elster Honeywell and Itron meters
  • 23 Feb 2020 - Aclara meters
• Middle Operating Capability (MOC)
  • 15 Mar 2020 - Elster Honeywell meters currently operated by MDS (Morrison Data Services)
  • 28 Jun 2020 - Secure meters operated by the Secure Meters group
• Final Operating Capability (FOC)
  • 26 Jul 2020 - Landis + Gyr (L+G) meters currently operated by either BG SMSO (Smart Meter System Operator), DXC or CGI Instant Energy (IE) and, if directed by Government, the EDMI meter group.

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