What is ECOES (and ECOES 2)?

What is ECOES?

Whenever you decide to change your energy supplier to get a better deal, a vast amount of background work takes place to move your account. You click a button on a comparison website or a supplier's page, and a few days later, your new tariff begins. The system that makes this fast, accurate transfer possible is the Electricity Central Online Enquiry Service, widely known as ECOES.

ECOES is the central database that holds the permanent records for roughly 30 million electricity supply points across Great Britain. It acts as the single source of truth for the energy industry. Every time a property is built, a new meter is installed, or a household changes supplier, the details are updated on this central network.

While the software platform is still commonly referred to as ECOES, the service is now formally known in industry regulations as the Electricity Enquiry Service (EES). Whether you call it ECOES or EES, its purpose remains the same: it ensures energy companies have the correct technical data to take over your supply without mixing up your address with a neighbour's, keeping the competitive energy market running smoothly.

What information does ECOES hold?

To protect consumer privacy, ECOES does not hold your personal financial information. It does not store your name, your bank details, or your credit history. Instead, it holds the technical and geographical data relating to the physical electricity connection at your property.

The most important piece of data stored on the system is your Meter Point Administration Number (MPAN). This is a unique 13-digit reference number assigned to your specific electricity supply line. Even if you change your supplier, change your physical meter, or move to a smart meter, your MPAN remains exactly the same. It is permanently tied to the property, not to the meter box or the person living there.

Alongside the MPAN, the database tracks the full postal address of the property, the identity of the current energy supplier, and the specific type of meter installed. It also records the local Distribution Network Operator (DNO) responsible for the cables leading to the house.

By holding this information centrally, ECOES prevents a common industry problem known as an erroneous transfer. This happens when a supplier accidentally takes over the wrong property, usually because of a mix-up with flat numbers or similar street names. Before a switch can go ahead, the new supplier must check ECOES to confirm that the address provided by the customer perfectly matches the MPAN on record. If the details do not align, the system flags the error so it can be corrected before the wrong household receives a final bill.

How ECOES speeds up energy switching

Historically, switching energy suppliers was a slow process. It routinely took between 17 and 21 days for suppliers to exchange data, verify meter details, and agree on a handover date. If any data was missing or incorrect, the delay could stretch even longer.

This changed significantly with the introduction of Ofgem's Faster Switching Programme in mid-2022. Under the current rules, a standard domestic energy switch must be completed within five working days. To achieve this, a new system called the Central Switching Service (CSS) was built by the Data Communications Company (DCC). The CSS works directly alongside the ECOES database to process transfers rapidly. Since its launch, the Central Switching Service has successfully processed over 27.5 million rapid switches.

When you switch, you normally do not need to contact your old supplier. Your new supplier manages the process through the Central Switching Service, while EES provides electricity supply-point data to help check the details. Your old supplier is notified as part of the switching process. They then generate your final bill based on the handover meter reading.

The 14-day cooling-off period trade-off

The shift to a five-working-day switch introduces a practical choice for consumers regarding their statutory rights. By law, you have a 14-day cooling-off period when you sign up for a new energy tariff. During this window, you can cancel the contract without giving a reason and without paying any exit fees.

Because switches now happen in five days, your new energy supply will usually start before your 14-day cooling-off period has finished. This is a deliberate design that allows you to access cheaper rates faster, rather than waiting weeks for the legal window to close before the new supplier can take over.

However, this creates a trade-off. You still retain the right to cancel the switch up until the 14th day. If you choose to cancel on day 12, the switch will be reversed and you will be returned to your old supplier. But because the new supplier actually provided your home with electricity between day 5 and day 12, you will have to pay them for the energy you used during that specific week. They will send you a short bill covering those days, charged at the rates you originally agreed to when you signed up.

Who has access to the ECOES database?

Most domestic household consumers cannot log into EES to check their own meter details or MPAN. Access is restricted to authorised users, although eligible non-domestic consumers can be given access to a portfolio of their own metering points.^[1]

Access is tightly controlled through a Data Access Matrix. Only authorised industry parties are granted login credentials. This includes energy suppliers, Distribution Network Operators (DNOs), and accredited third-party intermediaries (such as price comparison websites and metering equipment managers). Government bodies and law enforcement agencies, such as the police, can also request access for specific investigations, such as tracking electricity theft linked to illegal activities.

Who runs and manages the system?

The rules governing how energy companies use ECOES have undergone a major overhaul in recent years to reflect the modern energy market. Previously, the system was governed by the Master Registration Agreement (MRA) and administered by a company called MRASCo. These structures were abolished during Ofgem's Retail Code Consolidation project in late 2021.

Today, ECOES (or the Electricity Enquiry Service) is strictly governed by the Retail Energy Code (REC). This is a comprehensive regulatory framework designed to ensure all energy companies use consistent, accurate data to keep the market fair. The management and contractual responsibility for the database now sits with the Retail Energy Code Company (RECCo).

While RECCo sets the rules, the actual software and IT infrastructure for ECOES were designed and built by the C&C Group, who remain the contracted IT service provider.

The data that feeds into ECOES comes from regional network companies. Across Great Britain, the physical cables and wires are managed by regional Distribution Network Operators. Each DNO runs its own Meter Point Administration Service (MPAS). When a new house is built, the local MPAS assigns a new MPAN to the property and immediately feeds that information up into the central ECOES database so suppliers can see it.

Recent upgrades and the future of ECOES

The energy market is changing rapidly as the UK moves towards a grid powered by renewable sources like wind and solar. To support this, the ECOES portal and its background systems have been heavily updated to handle more complex information.

One of the biggest recent changes is the integration with the Market-wide Half Hourly Settlement (MHHS) programme. In the past, the energy industry settled its accounts based on broad estimates of when people used electricity. Now, the systems are being upgraded to handle granular data in 30-minute chunks, primarily gathered from smart meters.

EES is being updated to display and exchange the registration and metering data needed for MHHS. The wider MHHS arrangements use half-hourly meter data for settlement and can support dynamic, time-of-use tariffs. These tariffs may offer lower rates at particular times, so households can benefit by moving flexible use, such as EV charging, to those periods.

Following an Ofgem decision in December 2024, the Centralised Registration Service, which includes the Central Switching Service, will remain with the Data Communications Company (DCC). The service manages registrations for both electricity and gas, rather than relying entirely on EES data.