Monday, 12 October 2015

Analysis by Dr Fred Udo challenges accuracy of SEAI report

The reduction of CO2 emissions by Irish wind energy

Last year, SEAI issued a (revised) report on savings in the Irish system due to wind for 2012. I pointed out in a previous post that some of the assumptions they used resulted in greater CO2 savings than would have been the case in reality.

Dr Fred Udo has done an excellent analysis on this report, using more valid assumptions than the ones used in the SEAI report. He concludes that :

  1. SEAI admits there is increased fuel use due to the insertion of wind power in the grid.
  2. The authors try to minimize the efficiency losses by inflating the use of OCGT in the reference case.
  3. The CO2 calculation used in the PLEXOS model (used by both SEAI and Eirgrid) produces too low CO2 intensities, hence even the 30% loss found in the corrected calculation is too low.
  4. Corrected for self-energy (the energy required to build a new generation system around wind) we find a loss of 40% (from SEAI's calculated savings) for 15,3% wind penetration.

Dr Udo makes the distinction between a system with lots of hydro, like Denmark, and one without. Hydro is an efficient back up for wind as it can be turned on and off instantly, while gas generation loses its efficiency with increased amounts of intermittent wind. Yet, the Irish government continue to draw comparisons between Ireland and Denmark.

The full report can be read here :


  1. Many people judging this subject don't take into account the fact that the system must be kept alive and supplying demand for every single second of every day of every year, without as much as one eighth of a second break down. It's the same as the human heart. It is not the same as money in the pocket, where being broke for a day will not kill you. A better example might be a mountain climber having the special boots needed. Having only one boot is a serious inhibition, having two boots is just ideal but having three boots is a further inhibition. Any extra boots become a distraction, an extra weight to a point where he cannot climb at all and is extremely dangerous. Any extra generating capacity must replace existing capacity and wind cannot do that, Unfortunately policy makers refuse to hear this fact, the objective has nothing to do with out electricity supply and everything to do fooling their voters with this confidence trick.

    1. Thats true. When we hear claims that wind provided 25% of our electricity needs, this is an average figure of unreliable generation so its not the same as 25% supplied by dispatchable means such as gas. 50% wind is not much good if it was 0% at any point.