How Smart Meters work

A Smart Meter works by measuring the current flow and voltage at regular intervals and then adding this up to calculate the power used in a half hour period. Similarly for gas the flow is measured at regular intervals. This information can be sent to your In Home Display and to your supplier. Different communications technologies may be used in different kinds of premises for the Home Area Network to communicate with your In Home Display, and different technologies will be used in different parts of the country to allow the Wide Area Network to send data to and from the company providing the communications.

As well as measuring energy, meters are constantly monitoring their own performance and environment. For example they will report if they have an internal memory problem and report if the terminal cover is removed. In these cases your supplier may send someone to your home after contacting you.

End to End

The information from your meter goes first into a communications hub that is usually built into the electricity meter, and then through radio waves to the communications company. In the case of the SMETS2 meters it is the Data and Communications Company (DCC). From there it is sent on to the various DCC Services users who have a need for the data.

House to DCC to Supplier

We will now explain each leg of the end to end journey shown in the diagram above.

Energy Customers

In your home as an energy customer you will have a smart meter for electricity and a smart meter for gas (if you're dual fuel). Both meters communicate with a communications hub which is normally a part of the electricity meter however it could be separate if your gas smart meter is installed first. To power the communications in the gas meter a battery is used as it would be dangerous to use mains electricity.
In addition you will have a In Home Display which is powered though the mains and communicates with the meters through the same communications hub. Additionally in the future more gadgets could use the communications hub, provided they have the right security credentials.

Data and Communications Company (DCC)

To minimise costs for the long term use of SMETS2 meters the DCC went out to tender for the communications network having split the country into regions for this purpose. So depending where you are you could have one of two companies communicating with your meter, Arqiva Limited in the north and Telefonica (better known to us as O2) in the central and southern regions.

Once received by the DCC the data is processed by the Data Services provider, currently CGI UK Limited. Overall the whole of DCC is facilitated by Capita PLC.

DCC Service Users

From the DCC, the Smart Meter messages can be sent to various Service Users depending on the messages content. Electricity and gas suppliers and distribution network operators will all have a keen interest in the data from Smart Meters. They will use it for the following reasons:

  • Suppliers
    • Meter readings - for billing purposes
    • Half Hourly readings - for additional services or sophisticated products
    • Maintenance messages about the health of the meter - such as memory problems
    • Firmware messages - to update the software in the meter
    • Configuration messages - to set up new products
    • Pay As You Go messages - to top up PAYG credit
    • Tamper messages - to detect theft and security attacks
    • Export meter readings - to measure how much electricity your solar cells or wind turbine is passing back to the network for load management and to credit the customer depending on the commercial arrangement.

  • Distribution Network Operators
    • Power outage messages - to know when and where outages occur
    • Meter readings - for network billing to suppliers
    • Half Hourly readings - for network load planning
    • Voltage, Current and Power Factor readings - for network operation and planning.
    • Export meter readings - for network operation and planning.

  • Other Authorised Parties
    • Meters readings - to analyse and show you your energy usage
    • Half Hourly readings - to analyse and show you your particular energy profile shape.

Questions & Answers

What services do I have on a meter that's "gone dumb"?
On a meter that's "gone dumb" you will only retain the ability to see kWh on your IHD. As the supplier can't communicate with the meter they cannot send a tariff so the p/kWh rates and £ will not be updated. Additionally no meter readings can be automatically collected.

What does "going dumb" mean?
When a meter 'goes dumb' it means that the communications to the meter have stopped. This could be due to a communications failure or due to the current supplier not supporting the communication method to that meter.

What will energy companies do with the information they collect about my energy consumption?
Under Ofgem codes published July 2013, you can dictate how much data your energy supplier can retrieve from your smart meter and whether your supplier can share that information with third parties. See our Customer Rights page for your rights on meter readings. You can also decide whether or not your supplier can use that information for marketing purposes. Just call your supplier if you want to check or change your preferences.

How does a smart meter work?
A smart meter works by communicating with your energy supplier through a system operator, so the company will always have an accurate meter reading and there's no need for you to take a meter reading yourself. A communications module on the electricty meter talks to the gas meter and IHD (In Home Display). Smart meters can work in a variety of different ways, including using wireless mobile phone type technology to send data. See our How They Work page for more information.

Can my supply be turned off remotely?
Smart meters have the facility to remotely disconnect and reconnect both the electricity and gas supply. However most suppliers seem to have decided it is too dangerous to remotely disconnect or reconnect, as in the case of disconnection they cannot always be sure that the customer isn't relying on a supply for serious health reasons and in the case of reconnection the customer may have left a cooker on for example.

How do I top-up my smart meter PAYG if the mobile network is down?
Normally your PAYG top-up will be sent automatically to the smart meter, however if the communications link through the mobile network is not available then this cannot happen.
Firstly you can use the emergency credit that most suppliers offer. If that runs out you can enter the long authorisation number that you received when you paid for the credit into the meter or IHD to apply your credit. This very difficult to do on the meter so use the IHD if you can.

How do Smart Meters send data?
A communcation hub in the electricty meter gathers readings from the two meters sends them to the IHD (In Home Device) and also stores them ready for retrieval by the system operator. A Smart Meter sends data (readings and alerts) through the Wide Area Network (WAN) to the company responsible for collecting the data and passing it on to other businesses such as suppliers; for the latest SMETS2 meters this company will usually be the DCC (Data Communications Company) which the government has set up especially for this role. Depending on the Communications Service Provider, which varies by areas of the UK, the radio 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 meters around you to step to a meter which has direct communications with DCC. This form of communications looks like a mesh when you draw out the links between meters and is known as a Mesh.

Can I look at my energy usage on the internet?
You will be able to view your energy usage on the internet at some stage. Suppliers are all working on new systems to make this possible.

How much data is stored on a Smart Meter?
The specification for these Smart Meters requires 13 months worth of consumption data to be stored at the highest level of detail, which is at half hourly measurement intervals.

Can smart meters be upgraded?
Smart meters can have a firmware upgrade just like your computer or mobile phone. The upgrade will be used to fix faults and add new functionality and should be carried out in the background with little impact on the customer. Indeed this feature is being used to allow SMETS1 meters to be upgraded for the SMETS2 systems; this will allow them all to interoperate.

Why is two way communications important?
Smart meters send meter reading and event information to suppliers. Supplier can send product and payment details to the meter when you want to change your product or payment terms. Additionally this two way communications supports Pay As You Go for energy.

Are there special considerations for the location of a Smart Meter?
When a meter fitter first arrives at your premises they will usually check the signal available with a special tool and decide if the installation can go ahead; in some cases an additional aerial or alternate communications system can be used if the signal is poor. The Smart Meters must be fitted in place of or near your old meters as it is too expensive to move the incoming power cable and gas connection, and not good to have long cables from the main fuse (cutout) to the meter.

What is a smart meter?
A Smart Meter is a new kind of meter to measure your energy, they are available for electricity and gas. Smart meters allow communications to and from your energy supplier and distribution network operator, and they can therefore can send meter readings automatically. An In Home Display will be provided with your meter to allow you to see how much energy you are using and what it is costing. There have been a number of standards in the UK, but the latest is called a SMETS2 meter.

How often will my IHD (In Home Display) be updated with data from my meters?
Your IHD will be updated by your electricity meter about every 10 seconds and by your gas meter about every 30 minutes. The gas meter updates less often in order to preserve its battery life which in normal use is expected to be at least 10 years.

Can I have a smart meter if I'm a prepayment customer?
Yes. Smart meters work in both credit and prepayment modes. In fact, prepayment customers will have more flexible payment options available to them with smart meters, including remote top-up facilities.

How do I read a smart meter?
It is possible to read information from your smart meter, unfortunately there are many different makes out there with different controls, so please check our Documents page or contact your supplier for additional information.

How do I read an In Home Display?
The In Home Display (previously known as Smart Meter Display or Home Energy Monitor) has been designed to provide information to customers in their homes, and so should be easy to understand. For both electricity and gas it will display your energy consumption in either pounds and pence or kilowatt hours, helping you understand how you are using energy in your home at any given point in time. Unfortunately there are many different makes out there with different controls, so please check our Documents page or contact your supplier for additional information.

Are the meters battery powered?
The electricity meter is mains powered but the gas meter is battery powered. The gas meter battery can be replaced by a Smart Meter Installer and is excepted to last the life of the meter (10 to 15 years), however its life can be greatly reduced heavy communications such as repeated firmware updates.

Could my IHD (In Home Display) link to my neighbour's meters?
Your IHD is paired to your own meters by the installer. It won't pick up information from your neighbours and can't be used in another house. If you need a replacement IHD this will have to be paired with your meters.

Do I require a broadband connection or wi-fi in my home to be able to use a smart meter?
Smart meters don't need a broadband connection or wi-fi in your home as they use either the GSM (Global System for Mobile communications) mobile networks just like your mobile phone, or use a local mesh communications network (DCC only) to hop from meter to meter until a link to the GSM mobile network is found.

Do smart meters work with home generated renewable energy?
Traditional meters are only capable of recording consumption and consequently don't take into account any energy generated by a household. If you have or are planning to install solar panels or any other renewable energy generating system in your home, a smart meter will enable you to measure how much energy you produce. The smart meter will also calculate whether or not there is a surplus which you could sell back to the grid.
However as this is not a common requirement suppliers have been slow in implementing systems to support it - you will have to shop around for the supplier which can support your requirements.

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