Tuesday, 3 April 2018

Storms Linked to Power Station Trips

Eirgrid published this list of power station trips from the past few months:

I couldnt help but notice that most of these dates coincided with storms or very windy conditions:

5th october - Cyclone Xavier
12th october - Hurricane Ophelia
16th october - Hurricane Ophelia
21st october - Storm Brian
27th November - gale force winds
24th December - record wind penetration on the grid
3rd January - Storm Eleanor
17th January - Storm Fionn

It appears that as very high amounts of wind generation is allowed into the grid, the frequency can drop to a dangerously low level.

One of our key tasks is to maintain balance between electricity supply and electricity demand. Electrical frequency is the measure of balance between supply and demand. When supply and demand are balanced, the electrical frequency is at 50 Hz. We must maintain this balance on the system all day, every day. The normal operational frequency range is 49.8 Hz to 50.2 Hz [Eirgrid].

You can see from the above diagram that the frequency has dropped below 49.8Hz on a few occasions over this period.  As a result, the power station tripped and went offline. This then results in the frequency falling even further. At this stage, cutting demand is one of the few options open to the grid operator. This may explain some of the blackouts on these days.


  1. Here in the UK, the recent storms caused 3 gas power stations to go off line and high winds brought seaweed into a cooling reactor for a nuclear power station, which then had to be shut down for safety reasons. We also have long standing issues with damaged gas pipelines from europe which pushed the price of gas up to a record high. Thankfully the wind turbines were able to produce a record 30% of our energy mix during these storms and snow and when demand was high too. That's very impressive in my eyes.

    This is why this blog has zero credibility. it cherry picks data from one source of energy to paint a rose tinted picture. The authors refuse to give fossil fuels a bad name. They're scared of a renewable future and they don't believe in climate change. I bet they're all old men too.

    1. It seems to me that far from cherry-picking, the piece on the blog is fully focussed on under-frequency grid trips. This category of trip is a consequence of diminished mechanical inertia arising from a higher ratio of asynchronous to synchronous generation. The critique fails to identify the cause of the trips during recent storms that caused three gas power stations to go off line and which forced a loss of secondary cooling due to seaweed blockage at a nuclear power station.

      Credibility is scarcely dependent on "The authors refuse to give fossil fuels a bad name. They're scared of a renewable future and they don't believe in climate change". It is dependent on objective technical veracity, and it is no secret that in the engineering world of reality the grid frequency problem is becoming more and more expensive to manage with increasing asynchronous penetration. I would refer Anonymous to the many technical papers that have been published on this subject.

    2. During the Beast from the East, UK coal power was producing at full capacity. Coal was literally a life saver. So the UK has zero credibility as they want to shut down the remainder of the coal capacity. It is difficult to comprehend this level of stupidity. Ireland has much higher wind penetrations than 30% so the risk of a grid collapse is higher. Something the UK dont have to worry about, until they close all of their coal power. As Puzzled explained above, this is a highly technical subject but could have very real consequences for ordinary people, most of whom are unaware. Hence this blog.

  2. A "Trip" is term that denotes an electrical disconnect. In the case of a utility electrical generator trip, it is a disconnect of the generator (electricity source) from the national grid (electrical load). The disconnect may be initiated by a human (manual trip), an automatic generating plant protection element or an automatic electrical interface protection element.

    The normal electrical interface protection elements include (1) Over frequency >50.5Hz; (2) Under frequency <48Hz; (3) Over voltage >1.1pu; (4) Under voltage <0.9pu; (5) Rate of change of frequency >0.4 Hz/s; and (6) Vector shift >12°. It is not possible to define the cause of a trip without identifying the protection mode that initiated it and its magnitude.

    This would be useful in the case of the trips at the three gas-fired power stations cited by your correspondent.

  3. At 18 hours on 24/12/2017 MP39 at Moneypoint ceased generating electricity.Before it ceased it had generated 78.94 megawatts at 17.00 hours.. It recommenced generating on the 25/12/2017 at 7 hours producing 1.17 megawatts.From the 23/12/2017 to 25/12/2017 its output ranged from 1 megawatt to 150 megawatts in zig zag fashion. I doubt very much that seaweed caused this. May be the ESB or Eirgrid could elucidate further.

  4. How could a sea weed blockage impact on the Irish Grid when there are no Nuclear Power Stations on the Island of Ireland at all?

    What possible significance can climate change (true or false) have on a machine. The Electricity system in Ireland is a machine, same as a vacuum cleaner or a mouse trap.

  5. It all comes down to independent variables and their effect on the process (the electric grid). An independent variable will have an effect on the process, and there are two types of independent variables, feed forward and manipulated variables. A manipulated variable (MV) would be something like a power station base load rate. This base load rate may be from a gas plant, peat, coal, nuclear, it doesn't matter. Some guy adjusts an MV (gas rate flow setpoint, peat consumption rate etc) and poof, more 'lectricity. The problem is the feed forward input(s). A feed forward variable cannot be controlled, it must be accommodated. Wind is a feed forward variable, unless someone in the homeland has Borrum in a bag electrical production from wind cannot be controlled. As the percent of wind/solar into the grid increases, so will disturbances in grid stability. You will suffer, if you're OK with that so Gombeen men can make a buck off you, so be it. If you have a problem with people exploiting you however........

    1. Ireland has a massive housing crisis. There is no plan to deal with it. There is nothing on land management, no plan to acquire land, nothing. Government find it easier to take instructions from wind companies and vested interests like Eirgrid. The strange thing is they have no problem persuading landowners to give their land for wind farms, but these same farmers are reluctant to give it for housing.