Connection Charges and Security

Charges for generator or demand customers as part of a connection agreement.

Connection Agreements

When a generator or demand customer executes a Connection Agreement with EirGrid, we require specific security cover. A number of charges also apply to the generator or demand customer under the agreement. These include the following:

Connection Charges and Bonds

Connection Charges Bond

A Connection Charges Bond is one form of security demand customers and generators must provide. It is calculated using the shallow costs of the connection. 

The bond is due prior to the Consents Issue Date. It covers the balance of the connection charges yet to be paid.

Generator Connection Maximum Export Capacity (MEC) Bond

A generator capacity bond is often referred to as the MEC Bond. There are two MEC Bond Regimes. 

Bond Regime 1 which is applicable to:

  • Generators who were issued offers before 25 August 2009 (CER/09/138)
  • Non-renewable generators who were issued offers before 1 July 2013

Bond Regime 2 which is applicable to:

  • Renewable and non-renewable generators connecting to the distribution system who were issued offers after 25 August 2009
  • All non-renewable transmission connecting generators who were issued offers after 1 July 2013 (CER/13/145)

Non-Renewable Transmission connecting generators who received offers between 25 August 2009 and 1 July 2013 can choose between Bond Regime 1 or 2.

More Bond Regime details are covered in “Clause 24– Security under the Connection Agreement” of the General Conditions (CER/13/145)

Demand Connection - Maximum Import Capacity (MIC) Bond

A demand customer capacity bond is often referred to as the MIC Bond. It's used when customers fail to construct their facility in the specified time frame (within reason). It is put in place prior to Offer Execution.

The bond amount is calculated at the network capacity charge x 18 (months) x MIC (MW).

Least Cost Chargeable (LCC)

A connection charge is levied on the works for connecting a demand or generation customer to the system. We will identify the least cost way of connecting to the transmission system, known as the Least Cost Chargeable (LCC). 

For system reasons, we may choose an alternative connection method. If this is the case, the customer will only be charged for the LCC connection. Customers may request a connection method other than the LCC. 

For customer preferred methods, the customer will be liable for 100% of the costs of that connection method, including any additional deep reinforcements.

For Generation Customers

If the LCC is being built, the generator must pay 100% of the LCC. Any deep reinforcements to facilitate the connection are typically not charged to the generator.

For Demand Connections

If the LCC is being built, the demand customer must pay 50% of the LCC. Any deep reinforcements to facilitate the connection are typically not charged to the customer.


Transmission generator and demand customers are entitled to build or procure large elements of their own shallow connections. However, we still carry out works such as design approval, supervision, commissioning and final connection. Connection charges are payable for these works.

Connection Security

Pre-Energisation Data

Connection applications usually happen at an early stage of a project. As such, many applications are based on assumed data. Before a generator is connected, we usually need extra technical information. Typically, this includes:

  • The final choice of wind turbines or generator parameters
  • Information about dynamic modelling and harmonics

We need the information 12 months before connection. That allows us time to perform pre-connection technical studies, such as voltage, short circuit and dynamics. These studies ensure that the connection will not cause technical or safety issues.

The Information Note below sets out the PED process.

Dynamic Modelling

We monitor the quality of the power delivered on our power system. This is to make sure we supply high-quality electricity.

Dynamic modelling assesses the behaviour of new generators before they're installed on the network. You can see more details of our approach to power system quality simulation models on the page linked below.