Connecting Small Scale Generation

In general these generators are designed to switch off when the electricity network supply is disconnected.

This is a safety feature of the protection systems installed within these devices. This feature protects the generator itself and also ensures the generator does not create a potential hazard by making the external electricity network live in a fault situation.

It is however possible for certain generators to be installed in such a way that they can be operated when the electricity supply is disconnected. In order to do this the premises must be physically isolated from any connection to the external electricity network. This is a safety requirement under the NSAI Wiring Regulations and requires a changeover switch and other alterations to internal wiring within the premises in order to permit safe operation of such generation. More information on these generators, including what would be required to enable this in your own premises, can be obtained by contacting a registered Safe Electric electrician, a suitable generator installation company or by contacting a generator equipment manufacturer directly.

The cost of your bill may fall because you may not be drawing as much power from the electricity network as previously. However, there is no change to your standing charge which remains the same. 

Yes. You can connect a generator in parallel with ESB Networks provided the requirements in the document "Conditions Governing the Connection and Operation of Small Scale Generation" are met. To familiarise yourself with the process, please read this document at the following link (Download PDF | 582 KB).

There is an application fee of €1,223.85 (including VAT@23%) to apply for a Small Scale Generator connection. This fee covers a technical assessment of the Small Scale Generator on the electricity network. The technical assessment may determine that there are ESB Networks connection works required to connect the generator, the charge of which is to the customer. Any works required will be covered in the connection offer and a down payment request will issue with the connection offer. Payment of the down payment request is required in order to accept the connection offer and proceed with the connection of the generator.

Below is a non-exhaustive list of examples of ESB Networks connection works which may be required in order to connect a Small Scale Generator to the electricity network:

• Uprate of a transformer;

• Uprate of a section of overhead line or underground cable

Micro-Generation can be applied for using a simpler "inform and fit" process by submitting an NC6 Form (Download PDF | 99 KB) to ESB Networks. This application process can be used to connect a generator with a maximum export of 6kVA at single phase or 11kVA at three phase.

Mini-Generation enables the connection of inverter connected generators up to a maximum total of 17kVA at single phase or 50kVA at three phase. Applications in this range can be made by submitting an NC7 form (Download PDF | 532 KB) to ESB Networks and following the application process.

Small Scale Generation enables the connection of generators outside of those covered by the processes above and up to a maximum total of 200kVA. Inverter-connected generator applications in this range can be made by submitting an NC8 form (Download PDF | 97KB) to ESB Networks and following the application process. Note that for synchronous generator connections above the level covered under Micro-Generation and up to 200kVA, the NC5 form (Download PDF | 530 KB) is required to be submitted.

The largest generator which can be installed and applied for under the current Small Scale Generator Application Process is 200kVA.

It is possible to install a larger generator under alternative application processes. For further information, go to Connect a Renewable and Embedded Generator.

Under the Small Scale Generation application process, once the application process is complete and your installation has successfully completed an ESB Networks witness test we will update your MEC and notify your electricity supplier. As ESB Networks are not responsible for the purchase or sale of any electricity you will need to have an agreement with your Electricity Supplier to purchase the electricity exported.

For more information on how and when customers can expect to get paid for export, please see CRU’s website.

ESB Networks DAC are not responsible for the purchase or sale of any electricity. This is a matter for a customer and their electricity supplier.

For more information on how and when customers can expect to get paid for export, please visit  CRU's website.

For more information on Clean Export Tarriffs, please see Clean Export Tarriffs.

Eligibility criteria for payment for export to the grid are determined by CRU. For more information on the eligibility criteria, please see CRU's website.

For customers exporting between 50kVA and 200kVA your meter will be assessed to check its suitability to measure export. For the majority of customers in this range it is expected that the meter will be suitable to measure export and as such it will be configured to enable accurate readings to be taken by our team as part of the process and free of charge. For customers who have an installation which requires an alternative meter in order to measure export a quote will issue in advance for the work involved as this will be chargeable to the customer under the terms of the current regulated connection policy.

For customers under 50kVA, where a change of meter is required in order to measure export, the meter will be scheduled for replacement under the current phased Smart Metering Rollout Programme.

Currently the Smart Metering Rollout Programme is working to replace standard single phase domestic 24-hr meters (MCC01). Under the current rules announced by the CRU if you are eligible to receive a smart meter during this phase of the rollout, then you will need a smart meter to be paid for export. Where customers are eligible to have a smart meter installed, ESB Networks will endeavour to install a smart meter within four months of the completion of  the relevant application process. ESB Networks will be in contact in advance of your smart meter exchange. For more information please see the Smart Metering Rollout Programme page.. 

For customers up to 50kVA, if you are not currently eligible to receive a smart meter during this phase of the rollout, then CRU has outlined that you may be paid based on a deemed export calculation until such time as a suitable smart meter is available for your connection type and installed as part of the phased Smart Metering Rollout Programme. For more information on this, please see  CRU’s website.

Yes, it is acceptable to have a Total Installed Inverter Capacity (TIIC) greater than the site MEC in certain circumstances by using a suitable Export Limiting Scheme (ELS). When the Total Installed Inverter Capacity is greater than the MEC, you are required to provide a Manufacturer’s Export Limiting Scheme (ELS) Product Declaration Form – you can find the template here. This needs to be completed and signed by the Manufacturer. Following submission of the application, the level of MEC available on the existing network, or an outline of the reinforcement work required to enable a specific MEC, will only be determined by a specific technical study on the local network which will be completed as part of the process. The results of these findings can be impacted by variables such as distance from the transformer, available capacity, harmonics, potential imbalance, etc. As such we advise customers to await the completion of this study and receipt of their connection offer prior to fully committing to the final details of their installation.

Please note that for Mini-Generation and Small Scale Generation applications the Total Installed Inverter Capacity (TIIC) cannot be greater than Maximum Import Capacity (MIC).

Centralised G10 Protection Relays are required for all Small-Scale Generation Installations. These are not required for Microgeneration and Mini-Generation installations as the protection settings are within the Inverter. 

Yes, MV connections are eligible  under the Small-Scale Generation Scheme. For more details please read conditions-governing.

Yes, we can accommodate Small Scale Generation NC8/NC5 applications at the same time as an MIC change, once the MIC change application has also come in through the relevant application channel and is in process. Further information may be found at Changing Your Level of Supply.

The Small Scale Generation application will be on hold until such time that we are notified by the Client/Consultant, via email to dsominigeneration@esb.ie, that the MIC change has been finalised. Once confirmed we will move the application to the invoice stage if all details and supporting documents are in order.

Note: An MIC increase does not guarantee that you will the able to contract the full, requested MEC. This can only be determined by a specific technical study on the local network which will be completed as part of the process and will inform the MEC available, or an outline of reinforcement work which may be required to enable a specific MEC. The results of these findings can be impacted by variables such as distance from the transformer, available capacity, harmonics, potential imbalance etc. As such we advise customers to await the completion of this study and receipt of their connection offer prior to fully committing to the final details of their installation

If the generator either never parallels with the electricity network, or only parallels for 3 minutes when turning on/off and no more than 5 minutes a month, then they are just noted on the application form as existing Generation. The installed generation capacity associated with this generator is not included when assessing the overall level of generation installed on the site for the purpose of Mini-Gen, SSG or for assessment of Total Installed Generation. 

Limited Maximum Export Capacity (LMEC) is the term used for the Mini and Small Scale Generation connections which are available in  those areas of the electricity network which  have a high penetration of exporting generator connections already in place relative to the available electricity network capacity at higher voltage levels in that location. This means that at present there is limited capacity for further connection of generation export. 

For Inverter connected generators above 72A/phase (17kVA 1ph / 50kVA 3ph) a separate assessment of harmonics must be carried out. This involves taking the individual harmonics of the generator and assessing their individual and cumulative impact at the connection point. 

The harmonic values given in Amps (only format acceptable) up to a minimum of the 40th Harmonic will be available from the manufacturer or possibly from a Type Test Certificate provided by the manufacturer. 

For Synchronous Generators it is not expected at present that harmonics will be an issue so details are not currently being requested. 

In order to ensure continued grid safety, stability and reliability we need to offer this connection type in areas with limited electricity network capacity.  

The Limited Maximum Export Capacity (LMEC) restricts the amount of export available from new Mini and Small Scale Generation to no more than 6KVA (single phase), 11kVA (three phase), regardless of the size of the system installed. The limits on the size of the generator which can be installed will be determined by the technical characteristics of the local connection. In general, Limited Maximum Export Capacity (LMEC) connection offers will require the installation of an Export Limiting Scheme (ELS) to limit the system export to the permitted Maximum Export Capacity (MEC) to no more than 6KVA (single phase), 11kVA (Three Phase). More information on Export Limiting Scheme (ELS) can be found here.  

If your application falls into an Limited Maximum Export Capacity (LMEC) area an Export Limiting Scheme (ELS) will be mandatory. More information on  Export Limiting Scheme (ELS) can be found here. An  Export Limiting Scheme (ELS) scheme can be implemented using either a Reverse Power Relay or an  Export Limiting Scheme (ELS) control system. For an  Export Limiting Scheme (ELS) Control System you will be required to provide a Manufacturer’s Export Limiting Scheme Product Declaration Form – you can find the template here. This needs to be completed and signed by the Manufacturer. 

Currently Limited Maximum Export Capacity (LMEC) offers are only available to applicants' seeking connection under the Mini Generation and the Small-Scale Generation Schemes.  

This information can be found on the ESB Networks Availability Capacity Map webpage and with explanation of the map in the Capacity Map FAQ’s. 

Electrification will generally require the uprating of most substations and such uprated substations will have more capacity to accommodate generation export, both because the Transformers will be larger but also because of the increase in local load which will also absorb generation.  Planning and delivery of these projects will take a number of years to complete.

Additionally, dynamic management of load and generation will be a feature of future network operation and this is also likely to facilitate increased generation export.

The Generation Capacity Map on our website will be updated as and when available capacity changes throughout the country.