Accelerated Loss of Mains Change Programme


ALoMCP - Coronavirus Pandemic Response (updated 17th July 2020)

The ALoMCP is considered necessary by the Government1 and industry2 coronavirus pandemic guidance for the short to medium term security of supply and ensuring network resilience. Therefore, the Programme continues with the following additional guidance:

  • Applications approved in Windows 1 & 2 that had a Latest Valid LoM Change Date before or within September 2020, but had yet to complete the required works, have had their deadline extended by 3 months. A further extension to 4 August 2020 has been granted to any application that had an initial deadline of 24 March 2020.
  • Distribution Network Operators (DNOs)/Independent Distribution Network Operators (IDNOs) requirements to witness certain works and complete Sample Site Visits are unchanged. Where DNOs/IDNOs are unable to attend sites in person, they have agreed to complete witness testing and Sample Site Visits virtually.  Contractors should engage with the relevant DNO/IDNO for details of how to do this.
  • Payments due to applicants who have already completed their work, and had a Sample Site Visit conducted where applicable, will be processed as soon as is practicable under current working arrangements.
  • The Programme portal remains open for applications. We ask that the lead time provided in new applications accommodates any estimated delay due to Covid-19 conditions.

During these extraordinary COVID-19 conditions we understand that you may be unwilling or unable to progress your ALoMCP works within the allotted timeframe. The 3-month extension should mean that no applicant is penalised if they are unable to work within the Government guidance, or decides that the risk of undertaking works is too great.

The ALoMCP will update this response in line with Government advice.

1. Where reference is made to government guidance we take this to be the guidance published at;

2. The Ofgem open letter to Network Companies is published at;


What is the Accelerated Loss of Mains Change Programme (ALoMCP)?

This is a project led by National Grid Electricity System Operator (NGESO), Distribution Network Operators (DNOs) and Independent Distribution Network Operators (IDNOs). The objective of the project is to accelerate compliance with new requirements in the Distribution Code EREC G59. Owners of generation sites must make these changes by 31 August 2022.  After this date, owners who have not made the changes may be the subject of an enforcement programme.

Owners of sites who make the settings changes in the ALoMCP will be paid by the DNOs/IDNOs they are connected to. Payment is made based on the degree of work involved.  More details of the payment and the selection process can be found here.

Note: this Programme does not apply to domestic and similar generation that has been connected under EREC G83.  It only applies to generation connected before 01 February 2018 in accordance with EREC G59.

Why is the ALoMCP needed?

All generators that are connected to the distribution networks in Great Britain have loss of mains protection (LoM), one of the many protection requirements on the electricity system. This applies to generating plant within the scope of EREC G59, regardless of the type of generator e.g. wind or gas. LoM is designed to check if a generator is still connected to the main network. If a power line disconnects for a few seconds, the generator at the end of the line is temporarily disconnected from the wider network. This can be unsafe and lead to damage to the generator or anything the generator is powering, such as industrial equipment and even domestic appliances. Loss of Mains (LoM) protection is there to make sure generators shut down safely in these circumstances.

Updated Distribution Code requirements, which will make LoM less sensitive, must be implemented by generation owners by summer 2022. Where LoM is provided by vector shift, it must be removed and/or replaced with rate of change of frequency protection (RoCoF). The RoCoF setting requirement has been changed from 0.125 Hz/s to 1 Hz/s and now with a definite time delay of 500 milliseconds. It will mean NGESO will be able to operate the grid more efficiently.

Most of the costs incurred in managing the LoM risk on the electricity transmission system is to limit the RoCoF to below 0.125Hz/s. RoCoF is the rate at which frequency changes and is used to detect the absence of the connection to the system and disconnects the site if that RoCoF exceeds a specific value. Currently NGESO is limiting the RoCoF to below 0.125Hz/s so that generators with RoCoF protection are not inadvertently tripped. The costs are significant and are paid for by all of us through our electricity bills.

These costs could be reduced if RoCoF above 0.125Hz/s was allowed. To achieve this, we need to change the RoCoF settings at all sites where RoCoF protection has an existing setting of 0.2Hz/s or less.

Guidance about the Programme and timescales can be found on the registration portal. Click to read the contract terms and conditions.

The Fast Track Process

Since the ALoMCP launched in September 2019, LoM protection at 4,137 sites with a combined capacity of 7,914 MW has been updated by 30 June 2020 to meet the new code requirements. This is good progress but more changes need to be made rapidly to reduce increased LoM risks and costs resulting from the reduction in electricity demand from COVID-19 lockdown. The Fast Track Process has been introduced to help address this.

The Fast Track Process offers an additional payment of £5k to distributed generation sites that meet specific criteria and can commit to making required LoM protection changes quickly. The new process, which launched on 29 June 2020, will run in ‘schemes’. Each scheme will have its own qualifying criteria, cap, and additional payment. Sites that meet the following criteria are encouraged to apply on the registration portal:

  • minimum site capacity: 500 kW
  • maximum site capacity: less than 5,000 kW
  • type of LoM protection: RoCoF
  • pre-change RoCoF settings: up to and including 0.2 Hz/s.
  • lead time to completing the changes: less than or equal to 4 weeks.

For more information, please read the Payment Process Specification or contact your DNO/IDNO. To apply, please go to the registration portal.

Who is involved in the ALoMCP?

DNOs and IDNOs

Full contact details of all DNOs and IDNOs involved in the Programme can be found here. Owners with generation connected to any IDNO should register and the Programme team will ensure they are progressed with all the other applications.

The Programme Steering Group

This the key forum for stakeholders to make sure their views are considered in the overall management of the Programme, and its delivery by network licensees. It makes sure that the ALoMCP is run efficiently and for the benefit of stakeholders and consumers, recognising the importance of ensuring the changes to distributed generation protection are completed thoroughly and in a timely manner.

The Steering Group is comprised of representatives from Network licensees including:

  • National Grid ESO
  • the six UK Distribution Network Operators
  • a representative for participating independent Distribution Network Operators
  • up to three representatives of BSUoS payers
  • Up to three representatives of distributed generation owners
  • An observer appointed by Ofgem.

Additional information for participants

Contact information

If you have any questions regarding your application or the Programme in general, please contact us.

Generation Owners

Generation owners will complete the settings changes themselves using their own contractors or site management teams. To assist generators, the ENA has a directory of contractors who claim they have the capabilities to undertake this work. A generator is entitled to use any competent contractor to make the changes to their assets. 

Contractors listed on the directory of contractors are self-declared as competent but are not officially registered or formally approved by DNOs or the ENA.

A contractor does not have to be listed to participate in the Programme providing they can prove their competency to undertake the changes to the satisfaction of the generator.


Since the Programme launched in September 2019, LoM protection at 4,137 sites with a combined capacity of 7,914 MW has been updated by 30 June 2020. We want to make this process as easy as possible for you. But don’t just take our word for it; here are some testimonies from customers who have completed the process.

Oliver Leake, Earthmill Energy

“Our company manages a large fleet of wind turbines which required over 250 separate applications for ALoMCP funding. At first this seemed like a daunting task but the user-friendly registration portal made the process of submitting the applications very easy. Whenever I did have a question or if there was something I did not understand, the teams managing the process, at the DNOs and ENA, were friendly, helpful and guided me through the process. Applying for funding is a no brainer as this is likely to be a mandatory change later anyway but right now the works are paid for.”

Luke Andre, Director, Infer Energy Ltd

Aside from informing generator owners of impending grid compliance changes, the ALoCMP has proved to be a well organised transition scheme irrespective of the scale of generator. I encourage (qualifying) generation owners to take advantage while they can!!”

Document library

Window 1 Report

Window 2 Report

Window 3 Report

  • Meeting minutes from the Steering Group are listed by date and can be downloaded.

30 April 2020

8 April 2020

20 March 2020

28 January 2020

27 November 2019

The documents and information on this webpage will be updated as the ALoMCP progresses.