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Duplicate of Connecting generation to the electricity networks

This page is for those looking to connect generation to the electricity networks.

Generating electricity from renewable and energy-efficient sources is a key part of the government’s strategy to tackle climate change.

We believe that having the correct commercial and regulatory framework is the single most important factor in how network operators can support the government’s target for renewable and energy-efficient generation.

Compliance and requirements for generators

In April 2016 the EU Commission published 2016/631 The EU Network Code “Requirements for Generators” (RfG) which was incorporated into UK law and led to the development of two ENA documents:

  • EREC G98 “Requirements for the connection of Fully Type Tested Micro-generators (up to and including 16 A per phase) in parallel with public Low Voltage Distribution Networks on or after 27 April 2019”
  • EREC G99 “Requirements for the connection of generation equipment in parallel with public distribution networks on or after 27 April 2019”

While other factors will influence which requirements a connection application should be made, fundamentally if the connection is:

  • A generator with a capacity less than 3.68kW/phase then EREC G98 applies.
  • A generator with a capacity greater than 3.68kW/phase then EREC G99 applies.

Both documents have a set of application forms to use, which can be downloaded from the links below:

Both EREC G98 and EREC G99 contribute to supporting the Distribution Network Operators (DNOs) in meeting their Licence obligations and customers must be able to demonstrate compliance with the requirements in the relevant document when generation is commissioned.

Compliance is the responsibility of the customer who is quite often, but not always, the owner of the generation. Owners are required to make sure that generation equipment they purchase and install on their premises complies with the law.

Ensure generation equipment is compliant

In order to help determine what equipment is compliant, we provide a repository, the ENA Type Test Register, where equipment manufacturers can submit information about their products and make their own declarations of compliance with EREC G98 or EREC G99. The ENA Type Test Register enables all visitors to view the verification information for generation products designed to be installed in GB. Please note that it is not mandatory for manufacturers of generation products with a capacity greater than 3.68kW/phase to use this register to declare compliance information about their generation products there.

We review the information submitted and where the information is found to be correct and complete the entry will be marked “compliant”, all other submissions whether they are yet to be reviewed or have not yet provided all of the necessary correct information are detailed appropriately.

The onus is on manufacturers to produce equipment that is compliant with the legal requirements, and upon request (from owners, installers, developers, and DNOs) be able to demonstrate compliance supported by appropriate evidence. We urge manufacturers to ensure that their generation equipment is demonstrably compliant as this is in the interests of all their customers, from the supply chain to final owners.

EREC G98, which applies to generation equipment rated less than 3.68kW/phase, requires that manufacturers must always lodge their declarations of full compliance in the ENA Type Test Register.

Distributed generation connection guides

In order to help support a customer through the connections process we have produced the Distributed Generation Connection Guides, each with a corresponding ‘Summary’ guide. The sumary guides provide the most useful information in a condensed format.

Each ‘full’ guide has a flowchart that guides you to the most relevant connection guide for the distributed generation you are planning to install. The guides are intended to help you, as an owner of generation equipment or developer of generation projects, to connect your generating equipment to GB's electricity distribution networks. They are:

  • G98 Distributed Generation Connection Guide (Single Premises)
  • G98 Distributed Generation Connection Guide (Multiple Premises)
  • G98 Connecting Domestic-Scale Type Tested Generation Summary Guide (Single Premises)
  • G98 Connecting Domestic-Scale Type Tested Generation Summary Guide (Multiple Premises)
  • G99 Type A summary (Connection of generation >3.68kW)
  • G99 Connecting Type A Power Generating Modules Guide
  • G99 Types B-D summary (Connection of generation >3.68kW)
  • G99 Connecting Type B - D Power Generating Modules Guide


A full set of the guides for each document is available to be downloaded from the links below:

Application, compliance and decommissioning forms

In order to support the development of generation projects consistency in the connection application and assessment process we have produced forms which are available in our Resource library.

We don’t process these forms so please send your completed forms to the local network operator where your generation is to be connected.

Fast-track application process for small scale generation and storage

The electricity industry is experiencing a significant upturn in low voltage connection applications for small scale generation and energy storage schemes. Network operators, in conjunction with the government and Ofgem, have considered that some application and on-site testing requirements can be a barrier in terms of application timescales for small scale generation and storage schemes.

The revised fast track procedures for small scale generation (found in EREC G99) were implemented 9th November 2022, and are summarised below:

  1. The power generating modules are in a single installation.
  2. There are three possible small generation installation procedures, dependant on the number and size of generation devices.
  3. The total aggregate capacity of the generating units (including electricity storage devices) does not exceed 32 A per phase or 60 A per phase, dependant on the application procedure chosen.
  4. All of the generating units (including electricity storage devices) are connected via fully type tested inverters.
  5. The generating units will not operate when there is a loss of mains situation.
  6. Where required an EREC G100 compliant export limitation scheme is present that limits the export from the customer’s Installation to the Distribution Network. Engineering Recommendation G100 (2022) – "Technical Guidance for Customers' Export and Import Limitation Schemes" provides guidance on the connection of customer export or import limitation schemes (ELS) that operate in parallel with the Distribution Systems of licensed DNOs. You can find EREC G100 and its supporting EREC G100 appendices in our Resource library.

Fast-track application conditions

Only if all the conditions in EREC G99 are satisfied should the customer complete an application in a format as shown in G99 Form A1-2.

The planned commissioning date stated on the application form shall be between 10 working days and three months from the date that the application is submitted to the DNO. Confirmation of the commissioning of each power generating module shall be made no later than 28 days after commissioning (where commissioning tests and checks are not witnessed).

Confirmation shall be provided in a format as shown in G99 Form A3-2.

In addition, an EREC G100 Export Limitation Scheme Installation and Commissioning Tests form shall be submitted to the DNO to confirm that the export limitation scheme meets the requirements set out in EREC G100. Confirmation shall be provided in a format as shown in ENA EREC G100 Appendix B.