Notification of Industry Changes – Requirements for Generators

There are forthcoming changes to the Energy Networks Association’s (ENA) G83 and G59 engineering recommendation documents that are being implemented to comply with a change in European law.

From 27 April 2019, all generating equipment connected to any electricity distribution network, regardless of whether that network is owned by a Distribution Network Operator or by an Independent Distribution Network Operator (IDNO), must comply with the requirements of the ENA’s new engineering recommendation documents G98 and G99. Full details of these changes can be found at the following

Although these changes do not affect generating equipment that is already connected to the electricity distribution network, you may be affected by the change in the regulations if you either modify your existing equipment or you have projects that are yet to be connected to the distribution network.

For a project that is awaiting connection or modification the following rules apply:

Energisation Date prior to 27 April 2019:
If your connection will be energised prior to 27 April 2019, you may connect your generating plant either by:

a) Meeting the existing requirements of G83 or G59, as appropriate; or
b) Meeting the new requirements of G98 or G99, as appropriate.

Energisation Date on or after 27 April 2019:
If your connection will be energised on or after 27 April 2019, your generating plant must comply with the requirements of G98 or G99, as appropriate.

Alternatively, you may connect your generating plant under G83 or G59, as appropriate, but only if:

a) You had entered into a contract to buy your main generating plant prior to 17 May 2018; and
b) You provide the Network Operator you are connecting to with satisfactory documentary evidence that this was the case prior to 17 November 2018.

For example, the main generating plant would be defined as one or more of the principal items of equipment that are required to convert the primary source of energy into electricity such as the alternator or the generator transformer and which, once ordered, will determine the ability of the plant to meet the relevant technical requirements.

For any such projects looking to connect under G83 or G59 on or after 27 April 2019, you will need to have provided Network Operators with the following evidence, as a minimum:

I.     Documentation showing that you had contracted to purchase the main generating plant prior to 17
       May 2018, including evidence of the date of execution of that contract;
II.  The technical specification applicable to the main generating plant; and
III. The reference number provided on your quotation which will allow your network operator to cross-reference your evidence to the quotation you accepted.

Please note that, if you had not provided Network Operators with the necessary evidence prior to 17 November 2018, your generating plant will have to comply with the requirements of G98 or G99, as appropriate, if the connection is to be energised on or after 27 April 2019.

As the above changes are a legal requirement, if you fail to comply with the requirements of G98 or G99, as appropriate, on or after 27 April 2019, we will not be able to energise your connection until such a time as that non-compliance is rectified.

Modification of Generating Equipment:
You should also note that, if the criteria above do not apply to you but you significantly modify your generating equipment, you may also be required to comply with the new connection codes. Consequently, in accordance with the existing rules, you must discuss and agree any proposed modifications with your Network Operator in advance.

Compliance with the EU Network Code – Requirements for Generators

Briefing note for manufacturers, installers, developers and owners of new electricity generating equipment of all sizes.

The EU Network Code “Requirements for Generators” (RfG) became a legal requirement for all new generation equipment installed in Great Britain from 27 April 2019. These requirements have been translated into GB law via the Distribution Code (DCode) and DCode Annex 1 standards EREC G98 and EREC G99 (as well as National Grid ESO’s Grid Code).

The responsibility for compliance with the law (and hence with G98 or G99) is with the connection agreement holder who is generally the owner of the generation. Owners are required to make sure that generation equipment they purchase and install complies with the law.

When the RfG was initially drafted and passed into law by the European Commission, it was anticipated by legislators that 3rd party equipment certification bodies would provide the required confirmation of compliance to industry to ensure generation equipment connecting to electricity networks is compliant with the law. When the new requirements encompassed in G98 and G99 came into legal effect following the RfG implementation deadline on 27th April 2019, the industry in the UK did not at that time have any 3rd party equipment certification bodies offering these services to the market.

In the absence of a 3rd party equipment certification regime, ENA provides a repository, the ENA Type Test Register, where manufacturers can lodge their own declarations of compliance to G98 or G99 (  G98, which applies to domestic scale generation equipment rated at 16 amperes or less, requires that manufacturers must lodge their declarations of compliance in the ENA Type Test Register, but this is not mandatory under G99 for any generation equipment larger than 16 amperes.

Please note: ENA is not responsible for the accuracy or validity of the product information held in the register. ENA does not act as an equipment certification body and the presence of a manufacturer’s device on ENA’s Type Test Register does not indicate whether the device is compliant with the required specification or not.

With the increasing up-take in manufacturers registering their equipment on the Type Test Register, Distribution Network Operators (DNOs) and ENA have become aware that many of the declarations of compliance in the register are not complete or appear to have inconsistencies in the information that has been declared as meeting the requirements of G98 or G99.  As such, it is not possible to say if the generation equipment related to each incomplete declaration is compliant with the law.  In response to this observation, ENA has recently initiated a review of the completeness and sensibility of the records in the register.  Following the outcome of the review, ENA has flagged up obvious missing information to the relevant manufacturers requesting that they address these issues as a matter of urgency. ENA will be reviewing resubmitted data during July.  Please note that the scope of this review is not a review of the compliance of any generation equipment to G98 and G99.

Following on from this initial review, and in the absence of a 3rd party certification regime, DNOs and ENA remain concerned about the compliance of manufacturers’ equipment to the new G98 and G99.  In response to this concern ENA are now considering undertaking a more rigorous review of manufacturers’ submissions later in the summer.  The review would undertake an assessment on behalf of the DNOs to establish where compliance to G98 or G99 requirements may be of concern based on the evidence provided by manufacturers.  Currently there are over 400 entries in the ENA register and the process of reviewing these manufacturers’ submissions is a non-trivial task; ENA and DNOs are considering the most appropriate way of doing this.  This review is likely to continue until DNOs are satisfied that there are appropriate 3rd party certification bodies offering adequate service to the market.

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 this with appropriate evidence. ENA urge manufacturers to ensure that their generation equipment is demonstrably compliant, as it is in the interests of all their customers, including the supply chain of generation equipment to final owners.

ENA encourages all parties in the supply chain (owners, installers, developers and manufacturers) to maintain a dialogue seeking appropriate assurance and confirmation that generation equipment for the GB market is fully compliant with GB legal requirements.  To support a dialogue with stakeholders and DNOs around the connection of generation, ENA hold a Distributed Energy Resources (DER) Technical Forum.  This forum is open for all industry stakeholders to query the technical aspects of G99 and G99 with DNOs to garner a consistent understanding of the implementation by stakeholders and consistent application of the requirements by DNOs.  For more information on the DER Technical Forum please click here:

Where generation owners have already bought and installed generation equipment that might be found to be non-compliant, the relevant DNO can be expected to bring this to the attention of the owner in due course, along with any obvious possible mitigations.  However mitigations will be the responsibility of the owner and for the owner, installer and manufacturer to address in each case.


16 July 2019