An unexpected consequence of wind energy

As all ferry users across Argyll and the Isles today know well, the winds are blowing.

For Argyll’s main newsroom has a generator to protect internal systems from power supply problems. It cuts in automatically when there is a variation beyond the limits in the power coming in from the mains – and cuts out again, handing back to the mains supply when it has returned to normality.

We had only ever envisaged this as a protection against power cuts – but the experience of this morning has thrown up a different problem.

Our system switched to generator, then after an hour or so, switched briefly back to mains and almost immediately back to the generator.

No one else in the area had any power failures and Scottish Hydro had had none reported to it, so the problem was site specific.

It emerged that the generator protects the internal power system from both too low voltages and too high ones, taking over the supply in either case.

Since each of the blips and switchovers we had experienced had been accompanied by stronger swells of wind – heavy but not extreme, the wind farm in the hills was generating over capacity, creating ‘high volts’ voltages over the legal upper limit.

No one else in the vicinity had a problem because the over-limit voltages experienced in our system were modest enough not to create serious safety rick in well wired properties – whereas, with us, the generator is obviously set to respond to any variation outside the legal limits.

The setting of legal voltage limits is, of course, a necessary safety-first system – but will already have sensible tolerances built into it at the low and high ends of the allowed scale.

The question raised now is that there is an apparent disparity between the legal limits set to govern the supply to customers premises and the legal limits set to which wind turbines may generate before they are required to switch off for over production – and at which point another subsidy [for enforced non-production] kicks in. This requirement is not about an inability of the turbines to operate in strong winds but in the ability of our feeble power grid to cope with the additional power.

The legal voltage limits for the supply side and the demand side in this situation clearly ought, for the sake of safety, to marry. One is obviously currently incorrect. But which one?

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19 Responses to An unexpected consequence of wind energy

  1. For reasons of product liability the limits on your generator switchover are set according to national and local laws. If the wind turbines are generating voltages in excess of this limit then they must be fixed so that they do not. These limits are set to protect customer premises equipment and prevent electrical fires due to burnouts.

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    • We had to disconnect the generator in the afternoon, with repeated high voltages bringing it constantly into play – and then, without that protection and as you predict, we had a problem with a desktop computer hit by a power spike.
      From this experience, we suggest that everyone whose electricity supply receives local input from wind turbines should look at installing a spike protector on their core equipment.

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  2. “No one else in the area had any power failures and Scottish Hydro had had none reported to it, so the problem was site specific.”

    maybe you should have your equipment checked

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    • What we are reporting is information from the engineers who came out to check our fault.
      They read the high volts and testing the generator by deliberately switching it off and on again showed its response to that situation.
      Then the wind and the voltage dropped and the generator stayed off.
      The only other options was that, once activated by high volts, the generator – which, a replacement, is only months old had become unable to switch off when the mains returned to a voltage within the legal limits.
      But before the engineers came and after they had gone it had automatically switched off and handed back to the mains supply – which had obviously then returned to normal limits. So, on the evidence, this option was not a viable diagnosis.
      By the time the engineers left, the supply was just below the upper voltage limit and the generator stayed off. Later it cut in and then out a few times as the wind payed more games and with what will have been more high voltage surges.
      Voltage supplies higher than the legal limits reduce the life of properly rated electrical appliances by factors which cannot be accurately computed.

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  3. Your analysis of potential electrical engineering issues that might have found weakness in your system and nobody else’s is intriguing.

    When everyone else’s electrical systems are fine but yours is not, then this is highly suggestive that it is you that has a problem.

    But maybe you are right in your mererological observations of the bad wind creating out of phase, voltage irregular, spiked electricity that only affects you. Somehow I suspect not though.

    It was probably just a bad lump of coal in Longannet power station wot caused your system wobble.

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  4. And here is something else to ponder.

    Who provides the cleanest current. Scottish Hydro or Agyll’s main newsrooms back up generator.

    And do we think Argyll’s main newsrooms system protection can differentiate between electricity produced from coal, oil, gas, nuclear, hydro or wind. Seems that it can.

    And is it a diesel or petrol generator back up that we have and which one will provide the cleanest power. Serious questions to be sure, and questions that demand serious answers from serious folks capable of answering them.

    Mnnm?

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  5. Your generator switchover is too sensitive and could perhaps be adjusted a little(the legal limits are very conservative and most electrical goods will cope with quite large voltage variation), but you’re right; the grid is not up to the job of dealing with the windfarms that exist, never mind the ones proposed or in development. A battery-based UPS is probably your best bet to protect a PC from this kind of thing if adjusting your generator does not solve the problem or is not practicable.

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  6. The “renewables obligation” is, in simple terms, an obligation on the National Grid to buy all wind generated electricity whether they want it or not. The only way out is for the Grid to negotiate a price for the electricity not to be generated; rather a one-sided negotiation. The record price is over 50 p/kWh, more than three times the average RETAIL DOMESTIC price of electricity in the UK. A further point of interest is that when the backup generators sensing over-voltage kick in the load on the grid reduces so the voltage goes even higher… which will presumably set an even higher price per unit for wind not-generated electricity, and also trigger less sensitive backup generators, etc etc. A sort of chain reaction…and total insanity.

    To misquote Lord Alton, power corrupts and subsidised power corrupts absolutely.

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  7. Easily settled. Send a reporter (-do newspapers still have those?) to look at the Scottish Hydro company records of the voltages in the grid and at your substation. If there are legal limits then they will be required to keep proof of compliance.

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  8. Never has the uselessness of wind turbines been proved more clearly – they require continuous back up – so we are paying twice ( and dearly ) for one continuous electricity supply.

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  9. Not sure exactly what folks are talking about here.

    Is it the anti wind gripe that wind is expensive. Or is it a technical gripe about some equipment abnormality that may or may not have had an external gestation

    The perception that one’s electrical equipment is malfunctioning because of a perceived rise and fall in the wind is quite a analysis to draw, and simplitically maybe misunderstands the electromagnetic nature of electricity. That said, if the newsroom experienced it, then something is’nt quite right.

    Electricity as we know is generated by, and used by, many different things. Thus in terms of generation it can come from coal, oil, gas, hydro, pump storage, nuclear, wind or biomass sources, which sources all feed into the grid system as demand rises and fall.

    And yes, in monetary terms there is a complicated market that shuffles money between the players contributing in our out as circumstances appertain.

    Demand for electricity is the other side of generation and demand is varies as businesses and homes switch on and off electrical appliances. Current draw also changes as thing start up our power down, and this too has effect on the system. Think initial cranking amps when starting your car, and then when running, and you get the gist.

    The complaint that the Newsroom makes is that they think surges have been sustained in their supply resulting in equipment malfunction. Now whilst these surges have been described as both high and low, the nature of power, and it’s potential iregularirlties are just a litle more complicated. As are the causes external, and maybe internal.

    Thinking of the power as a sinosoidal wave form best visualised on an ossiliscope, the IEE identify 7 main classes of fault. Sag, swell, interuption, wave form irregularity, transitory, overvoltage, undervoltage are I think some of the classes. It is not readily apparent which one or more the newsroom sustained.

    Even less apparent, is the cause and whether it was internal, internal, a combination of both.

    Indeed, as mentioned earlier demand and switching is occuring all the time all over the network, notwithstanding extraneous environmntal impacts such a weather, and by weather I don’t just mean wind.

    So, I do hope that the hypothesis that wind speed variability is the cause of the newsrooms woes is unfounded. Electricity is an essential part of everday life, and computer systems are an important part of that to. Generating power is only half the story.

    As for wind, well it will always be a villain for some.

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  10. Given the heavy involvement of Germany-based multinational energy companies in the Argyll windfarming industry at An Suidhe and elsewhere, this afternoon’s BBC R4 programme – ‘Costing the Earth – Berlin’s Big Gamble’ – should be very interesting.

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    • I like wind and i’m not impressed by the nimbys’ arguments. They say it is unsightly, but so are nuclear power stations and coal fired power stations. and a hell a lot more dangerous and polluting too.
      Wave and tidal power is the most interesting. However it is good to see that this impressive SNP government is powering away with its objective of 100% power from renewable sources by the year 2020. Excellent news and this will make one of the first countries on the planet to do so, so congratulations to Alex Salmond and Co.

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    • Listening to the Germans banging on about how superior their “disposition” is, one is reminded that they started two world wars and lost both of them so they are not as clever as they think they are.

      Professor RV Jones wrote a fascinating book on how blinkered a nation they were – he was referring to their science.

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  11. RW, I am sure it will be an interesting programme to listen to.

    As to BBC Radio 4′s programme title of Berlin’s Big Gamble, well the German manufacturing industry has ” gambolled” along very nicely over the years to become Europe’s top manufacturing and engineering economy.

    Thanks for noting. Will listen in on the i.player thing and hopefully the programme will be objective listening.

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  12. Ah Hans, so it’s the not so clever Germans that we want to attack now.

    Started two world wars did they now Mr Blix. And lost them both too I hear you say. My my my, we are a bit of a bovver boy.

    And what does Newsie say about this rampant loyalism.

    The filth of unionist thugs throwing petrol bombs into police cars in support of a their virulent unionism is difficult to understand But it is little different from your vile xenophobic and racist attack on our German neighbours.

    British unionism at it’s finest perchance?

    Clearly, Newsie by her predilections is happy with these sentiments. But why stop at the Germans. What about the Irish, or the Italians or the folks of Asian antecedents. Are they people that unionists should equally despise.

    Sour vile and offensive comments, right minded people will want to rid themselves of this rancid manifestation of Britishism because there is no place for such sentiment in a modern outward looking Scotland.

    As for the two world wars, I would have preferred if they had never been fought in the first place. The slaughter was a stain on humanity as anyone who lost loved ones will know, and there was no winner.

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