Terms of reference for EirGrid review published

The panel asked to examine the EirGrid Grid West and Grid Link projects has concluded its deliberations and has now finalised and approved the Terms of Reference for the review.

The panel are set to conduct a comprehensive, route specific studies/reports of fully undergrounded and overhead options for each of the GW and GL projects, including assessments of potential environmental impacts, technical efficacy and cost factors. The studies/reports will be undertaken or commissioned by Eirgrid in accordance with those Terms of Reference set by the Panel who will also oversee EirGrid’s study/reporting process.


The Panel also considered issues in respect of the North South (N/S) Transmission Line project which the Minister had raised with the Chairperson, subsequent to the Government decision. The Minister had asked the Chairperson to consider what, if anything, the Panel could do with regard to the North South project (N/S).

While the N/S project is not covered by the Government’s decision, having discussed the Minister’s request, and in the light of the finalised Terms of Reference for the studies/reports of fully undergrounded and overhead options for each of the GW and GL projects, the Panel decided that it would provide an opinion to the Minister on the compatibility of the methodologies to be employed on the GW and GL projects with what has already been done (i.e. up to 2 May 2014, being the date that the Panel decided to examine the N/S project) on the North South Transmission Line project.

Terms of Reference

For each of the Grid West and Grid Link projects undergrounding and overhead options will be assessed and analysed in respect of Technical, Economic and Environmental characteristics. This will be done to comparable levels of detail for each option and set out in a manner that facilitates comparison between them. In respect of each network reinforcement option, the study/report should concern evaluation of the particular route most suited to use of that option. In each case, any significant assumptions made and the sources of data used should be clearly stated.

1. Technical
The technical analysis will include appraisal of the following:
a. Compliance with all relevant safety standards;
b. Compliance with system reliability and security standards;
c. The average failure rates during normal operation, average repair times and availabilities of the main elements of each option;
d. The expected impact on reliability of supply of unavailability of the development;
e. Implementation timelines, including procurement and availability of key equipment and resources;
f. The extent to which future reinforcement of, and/or connection to, the transmission network is facilitated;
g. The risk associated with use of any untried technology solution that would be required as part of a development option; and
h. Compliance with good utility practice.

2. Economic
The economic analysis will include appraisal of the following:
a. Project pre-engineering costs, including costs of evaluation of route, line technology and substation options;
b. Project implementation costs including:
•cost of procurement, installation and commissioning of overhead line and/or underground cable for the required continuous pre-fault, continuous post-fault and short-term post-fault ratings;
•costs of substations including procurement, installation and commissioning of required protection and control equipment and any equipment necessary for compliance with relevant technical standards;
•all relevant civil works for construction, including: for access to sites; for any necessary river/road/rail crossings or diversions, any tunnels necessary for any sections of underground cable, and for towers plus their foundations for sections of overhead line; and for post-construction restoration;
•Third Party Payments (wayleaves, community gain, rates etc);
•Interest During Construction; and
•the costs of any environmental monitoring deemed necessary to mitigate the impact of the development during construction or ongoing operation.
c. Project life cycle costs (including Losses, Operation & Maintenance, Decommissioning and the costs of retaining any necessary specialist repair teams);
d. The expected costs to operation of the Single Electricity Market arising from unavailability of the development; and
e. Estimates of the range of uncertainty attaching to all of the cost components under all options.

3. Environmental
The environmental analysis should be particular to each network reinforcement option and its associated route and substation locations with each option developed in accordance with best practice. The analysis will include:
a. The environmental impact of OHL and UGC options on the following:
•Biodiversity, flora and fauna;
•Water (surface, ground, estuarine and coastal);
• Soil;
•Landscape and Visual;
•Cultural Heritage (architectural and archaeological heritage);
•Climatic Factors;
•Material Assets;
•Tourism; and
•Traffic and noise.

1. A distinction should be made between the impact (the action being taken) and the effect (the change resulting from that action).
2. The type of effect should be identified (e.g. positive/beneficial, negative/adverse, direct, indirect, cumulative, short-, medium-, long-term, permanent, temporary).
3. The assessment should identify all likely significant environmental effects.

b. Identification of, and potential for impact and effect (e.g. positive/beneficial, negative/adverse, direct, indirect, cumulative, short-, medium-, long-term, permanent, temporary) upon, any Natura 2000 and/or other sites with environmental designations;
c. Potential impacts in the construction phase and during on-going operation, including in the event of any necessary repair to the installation;
d. Potential for imposing new limits on existing land use, both during the construction phase and during on-going operation; and
e. Proposed mitigation measures, their effectiveness and cost.


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