Questions for EirGrid

electric shock

There has been intense speculation about EirGrid’s announcement on GridLink, and the miracle cure in the form of “series compensation”.


I am not an engineer or very technical-minded, and even when some engineering friends tried to explain it to me in what they regarded as simple terminology, I left with my head spinning.


Accordingly I decided to find out for myself, by researching other people’s work that was written in language that I think I understand. After reading a number of papers I found two sources which seem clearer than the rest.


Jawnsy’s Journal on Life, Software and Engineering:

“The main purpose of series compensation in power systems is to decrease the reactive impedance of the transmission line to reduce voltage drop over long distances and to reduce the Ferranti effect. By adding series capacitors to the line, engineers can compensate for the physical inductance inherent in the transmission line. The voltage drop across the line is reduced with more compensation, allowing more power to be received by the load for any given sending power. Two main types of series compensation are fixed series compensation, and thyristor controlled series compensation, each with their own advantages.”


As I understand it, the longer a transmission line is the greater the resistance is, and so the weaker the power is when it comes out on the other side. By inserting capacitors along the length of the line at fairly short intervals, this allows the line to be juiced up continuously so that it comes out as strong as it went in.

The obvious question here is how many capacitors are we talking about, and how big (and ugly) are they?


Series Capacitors for Increased Power Transmission Capability of a 500 kV Grid Intertie” Rolf Gruenbaum, Jon Rasmussen, Chun Li :

“As power demand increases in many parts of the world, power transmission needs to be developed, as well. The building of more power lines may not be the best way, however, as transmission lines cost a lot of money, take considerable time to construct, and are subject to severe environmental constraints.

With series compensation, the power transmission capability of existing, long lines can be increased considerably. Likewise, in green-field projects, the number of parallel lines can be kept to a minimum by using series compensation from the outset. This can be utilized to benefit when large amounts of power need to be transmitted over long distances to consumer areas.”

Sounds great, existing lines becoming stronger, no need to increase the number of lines on existing routes, therefore considerably cheaper than the GridLink option (which was going to bankrupt this country, again).

The question I have here is will it work on shorter lines? In comparison to big countries like Russia, the USA and Canada, Ireland is tiny. Added to that is the fact that we are not talking about lines traversing the entire country, but only on the GridLink route from Cork to Kildare – that is hardly a vast distance. Is series compensation stable on shorter lines or is it only suitable for very long lines in remote places?

The other question is health related. If the ordinary lines are going to carry considerably more current, will this not mean a much stronger electromagnetic field which is much closer to the ground? Does this not increase the emissions and therefore increase the health hazard?


As you can see, my reading has led me to have a lot of questions that need to be answered by Eirgrid:

– Does series compensation mean an increase in emissions and therefore greater danger to human health than that posed by the super pylons?
– This technology was originally developed to carry power over vast distances (in countries like Russia, USA and Canada) without having to increase the carrying capacity of the transmission lines. Is it suitable for use in a small country, near human populations, over short distances?
– What is meant by “voltage reversal” and will it destabilise a relatively small power grid like Ireland’s?
– What is a “current reversal” and is there a chance of power leaks, again very hazardous to human life?

So many questions, but radio silence from Eirgrid.


My greatest fear is that the postponement of GridLink and the mentioning (without details) of the “new technology” is a stunt to silence the anti-pylon community groups before the election and once the election is over, EirGrid will suddenly discover that series compensation is “unsuitable” or “not viable” and the pylon option will be back on the table.


We need to see the modelling data for series compensation so that it can be independently verified and confirmed that it is fit for purpose and suits the needs of the national energy grid. We also need to see the emissions data calculated for the series compensated lines as opposed to current emissions data on those same lines to determine its safety for human (and animal) populations.


EirGrid, you need to answer these questions now, or it is impossible to believe you.


If Minister Paudie Coffey’s claims to have been instrumental in halting GridLink are true, he must have considerable influence over EirGrid. I would call on the Minister, as an elected public representative, to direct EirGrid to deliver this information – modelling data and emissions data – so that the public can make up its own mind before the election.

About Neil van Dokkum

Neil van Dokkum (B. SocSc; LLB; LLM; PGC Con.Lit) Neil is a law lecturer and has been so since arriving in Ireland from South Africa in 2002. Prior to that Neil worked in a leading firm of solicitors from 1987-1992, before being admitted as an Advocate of the Supreme Court of South Africa (a barrister) in 1992. He published three books in South Africa on employment law and unfair dismissal, as well as being published in numerous national and international peer-reviewed journals. Neil currently specialises in employment law, medical negligence law, family law and child protection law. He dabbles in EU law (procurement and energy). Neil retired from full-time practice in 2002 to take up a lecturing post. He has published three books since then, “Nursing Law for Irish Students (2005); “Evidence” (2007); and “Nursing Law for Students in Ireland” (2011). His current interest is the area of disability as a politico-economic construct. Neil is very happily married to Fiona, and they have two sons, Rory and Ian.
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6 Responses to Questions for EirGrid

  1. Pat Swords says:

    Well those questions above are environmental information. You have rights of access to such environmental information, see below:

    So one of the groups should write a formal Access to Information on the Environment (AIE) Request to Eirgrid, as to the environmental information they hold as the basis for this technology solution and the environmental impacts associated it.

    It has already been established that Eirgrid is a public authority subject to the AIE regulations:

    • Neil van Dokkum says:


      Somebody else suggested that as well, but I would be concerned that EirGrid could hide behind Section 36 of the FOI Act: “commercially sensitive information”.

      It might be worth a try anyway.

  2. Pat Swords says:

    Worth more than a try, by people already having ‘pushed the boat out’; claiming it is ‘commercially sensitive information’ in order to restrict access, is now quite a difficult thing for the likes of Eirgrid to do:

  3. Pingback: Questions for EirGrid | Deise against Pylons

  4. fclauson says:

    I have a “commercially sensitive” Appeal in to the OCEI currently against ESB Networks – they are trying to propose the energy generated by a wind farm is “commercially sensitive” while I am saying that it has an effect on the environment (EMF etc ) and hence cannot be with held

    watch this space …….

    • Neil van Dokkum says:

      You are the FOI expert. Why don’t you put together an FOI request to EirGrid on series transmission and emissions data? I can have a look at it but I cannot claim to have any FOI expertise!

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