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Accelerated Loss-of-Mains Change Programme (ALoMCP)

Accelerated Loss-of-Mains Change Programme

Accelerated Loss-of-Mains Change Programme

The way renewable energy generation sites are disconnected from the grid during grid disturbances is changing. Older generators installed before February 2018 with ‘G59’ relays must get them updated by September 2022. For those that act quickly, it should be possible to get the costs reimbursed by the Accelerated Loss-of-Mains Change Programme (ALoMCP).


Small scale electricity generators above 11 kW output (three-phase) have a ‘G59 relay’ which monitors the voltage, frequency and checks for power cuts and disturbances. If it detects an anomaly, it disconnects the generator from the grid. Historically the settings used have been very tight, which leads to renewable generators being disconnected in milliseconds if there is the slightest disturbance on the grid. When renewable energy generation only made up a tiny proportion of the overall generation, it wasn’t a problem if they all disconnected at the same time because of a grid disturbance. Now that renewables make up a significant proportion of the UK’s generation, if they all simultaneously disconnected because of a minor grid disturbance, the sudden loss of generation capacity could cause the grid frequency to suddenly fall and the grid to crash – clearly this would be a problem!

As part of the future plans to make the grid suitable for more decentralised renewable generators, the G59 rules have been updated to G99, which is a much smarter system that allows generators to ride-through minor faults without disconnecting and generally not cause significant amounts of generating capacity to disconnect all at the same time. As part of the process of introducing the new G99 rules, older generators connected under G59 are required to change some of the settings on their G59 relays to make them more tolerant of minor faults and prevent the mass-disconnection of generation capacity.

So what does it mean to you?

All owners of generation sites connected under the old G59 rules must update their G59 settings before September 2022, or potentially face enforcement action. Once this is done, your generator will be less susceptible to nuisance tripping and should operate for longer periods between grid disconnection events. If you act quickly, there is funding available to implement these changes.

If your site uses a configurable G59 relay, such as the ComAp MainsPro relay, the process is ‘relatively’ straightforward and the MainsPro relay can be updated with the new settings and re-tested and a new test certificate issued. In this case funding of up to £1,500 + VAT is available.

If your site has the G59 settings embedded inside the main controller hardware, such as in the older SCS hydro controllers, then the main control board may need replacing. In this case the new control board would be factory G59 tested and supplied with a new test certificate, then it could be installed at the site. In this case increased funding is available of up to £4,000 + VAT to cover the costs of the hardware.

For sites with multiple generators the additional generators may get a reduced amount – we can clarify this once we have more details of your site.

How can Renewables First help?

Renewables First can take care of everything and guide you through the process to get reimbursed for the costs incurred (though note we cannot guarantee your claim will be successful, but it should be if you act quickly). The order of works is:

  • Complete a form that we will send you to fill in with details of your generation site.
  • Compile supporting evidence required to make Energy Networks Association (ENA) application.
  • We will make the online application via the ENA Portal on your behalf.
  • You will receive an ‘offer’ to fund the proposed upgrade works.
  • Renewables First will visit site, make the required changes and complete a new G59 test and issue a certificate.
  • We will complete the ‘assurance activities’ and submit these via the ENA Portal.
  • In due course you should receive the payment for the works direct from the ENA.

The ENA has designated a number of ‘application process windows, as shown below:

ENA Application Process Windows
Window Start End Duration
Window 1 2nd Oct 2019 12th Nov 2019 6 Weeks
Window 2 13th Nov 2019 11th Feb 2020 3 Months
Window 3 12th Feb 2020 12th May 2020 3 Months
Window 4 13th May 2020 11th Aug 2020 3 Months

Note that there is no commitment from the ENA to have further ‘windows’ after these initial four, so there is no guarantee of funding to make the required changes after 11th August 2020.

What should you do now?

If you would like Renewables First to sort out the updates to your G59 settings, please either ask your contact to get things moving, or alternatively send us an enquiry then we will get in touch about the next steps.

Are you considering a low carbon renewable energy project?

Renewables First have considerable experience and full project capability, from initial feasibility studies through to system design and installation for hydro, wind and water source heat pump systems.

Read more about renewable energy in our Hydro Learning Centre and Wind Learning Centre. Alternatively, contact us about a feasibility study today.