El Hierro August 2016 performance update


During August the hybrid wind-hydro Gorona del Viento (GdV) plant achieved 55.6% renewables generation, higher than the 47.9% achieved in August 2015 but lower than the 65.9% achieved in July. The decrease relative to July was a caused by wind lulls and the increase relative to 2015 was a result of two periods of 100% renewables generation totalling 79 hours. Total renewables generation since full operations began at GdV in June 2015 is now 38.7%, up from 37.8% at the beginning of the month. Data on GdV plant layout, operation and capacities are given in the September update. Previous posts on GdV are accessible through the El Hierro Portal.


Figure 1 shows daily mean percent renewables generation since June 27, 2015 (data from Red Eléctrica de España (REE))::

Figure 1: Daily mean GdV percent renewables generation since June 27, 2015.

The Table below updates the GdV monthly grid statistics:

Figure 2 shows the REE 10-minute generation data for the month:

Figure 2: 10-minute REE grid data for GdV, August 2016

Figure 3 shows 3-hour wind speed readings at El Hierro airport 3km north of GdV:

Figure 3: Wind speeds at El Hierro airport, August 2016

And Figure 4 is an XY plot comparing airport wind speeds with gross GdV wind generation during August. Overall the class averages show the plot behaving as one would expect it to, but the scatter is extreme. It suggests that wind speed is only one of the variables affecting GdV wind output.

Figure 4: XY plot comparing airport wind speeds with gross GdV wind generation, August 2016

As for what other factors might be, suspicion has to fall on turbulence. GdV’s turbines are located on a ridgetop in an area of high relief where topography could cause gusting and abrupt changes in wind direction. The image below gives some idea of how irregular the topography in the area is:

Figure 5: Topography around the GdV wind park (image credit Thomasnet)

Finally, Figure 6 zeroes in on the interesting period during August 5 and 6. Beginning around 3am on the August 5 gross wind generation (including pumping) was briefly cut from 6MW to zero, broadly coinciding with a decrease in airport wind speed from 10 to 6m/s over the next three hours. We have no wind records for GdV so this is speculation, but there would seem to be no reason other than turbulence to cut wind generation to zero – 6m/s is enough to generate 4MW of wind power on average (Figure 4). Following this there were only minor squirts of wind even though wind speeds briefly recovered around 3am on August 6 and after 3pm on August 6. Wind generation in fact did not return to “normal” high wind levels until airport winds stabilized at 8m/s after 9pm on August 6:

Figure 6: GdV Generation during August 5 and 6, 2016

Equally interesting is the performance of hydro over this period. Hydro replaced wind after the wind shutoff at 3am on August 5 and was used for load-following with no increase in diesel generation. But around 2pm diesel generation was abruptly increased from 1.6 to 3.2MW, about an hour later to 4.3MW and about three hours after that to as much as 5.5MW. Because hydro generation is, or at least should be, synchronous, there is no reason to replace it with diesel to maintain grid stability. So why was this done? Speculating once again, I suspect the reason was that GdV was rapidly depleting its reservoir storage. So after 7pm on August 5 hydro generation was reduced to a trickle until the wind increased to the point where uphill pumping could begin the recharging process late on August 6. And how much hydro was sent to the grid over these two days? About 66MWh, roughly a quarter of the reservoirs’ design capacity. This may in fact represent all of the power the hydro system is capable of generating under current conditions.

If history repeats itself September 2016 will inaugurate an extended period of low-wind conditions during which GdV’s renewables output will fall drastically (Figure 1). It will be interesting to see whether it does, so stay tuned.

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80 Responses to El Hierro August 2016 performance update

  1. Euan Mearns says:

    Roger, thanks for interesting update. We will indeed be interested to see how the wind blows in September. We are hopefully heading for the Canaries in about 6 weeks. Our favourite Island is Fuerta Ventura which has a proper wind park which I will photograph and film.

    The poor correlation between airport wind and power generation is a puzzle. It could be turbulence, but I’m not sure I buy that story. As we should all know, wind should blow more strongly and more regularly at altitude. The upper left and lower right quadrants are being well behaved. It is the 4, 5, 6, 7 and 8 ms-1 classes that are aberrant where you can have wind at airport but near zero power output. Its very strange! Is there any information on wind direction?

    Another possibility is the presence of a local wind at the airport. For example sea breezes. Is there any correlation between the 4 to 8 ms-1 anomalies and month?

    • Euan: During August the wind was almost always blowing from between NW and NE. Wind speeds were usually lowest during the daytime, suggesting that sea breezes were not a factor.

      Here are a couple of images that might be helpful. First the airport weather station (the stone building in the foreground) looking northeast. It won’t make WMO class 1 but it should give representative wind measurements:

      Second the location of the airport weather station relative to the GdV wind park:

      I’m going to take a quick look at whether there is any difference between NE, N and NW winds. Stand by.

    • Kees van der Pool says:

      Hi Euan,

      You wrote:’The poor correlation between airport wind and power generation is a puzzle. It could be turbulence, but I’m not sure I buy that story. As we should all know, wind should blow more strongly and more regularly at altitude’.

      Not really a puzzle.You are right as far as the ‘more strongly at altitude’ is concerned so poor correlation because the airport is at sea level and the windpark at about 500m. However, the windpark is on a ridge and more ore less in the lee of a thousand meter high cindercone so the ‘more regularly at altitude’ is out of the window. In published ‘windpower in the mountains’ studies, the term ‘three dimensional wind’ is used as opposed to a well-behaved laminar flow.
      This causes the overall load on the blades of the windmills to be uneven and shortens bearing life, among other things.
      This is probably the reason for the curtailment of the power output, which is wasted anyway during the windy months. Enercon equipped the E-70 blades with (non standard) strain gauges to keep an eye on things and shut the park down if necessary.
      If the operational judgement is between wasting power by pumping water around and a shortened lifespan, the choice is clear.

      Best,
      Kees.

  2. Simon Cove says:

    Hi Roger

    I find this site interesting. I sit as a concerned person worried about climate change but unsure whether I should be very worried – is certainly warm this year but the models appear to have slowed – in fairness to all scientists involved is a very tough subject. I’m all in favour of looking after our single planet – money spent researching that is well spent. Impossible to know the ideal route. Incidentally, I’m certainly worried about species extinction and people astro-turfing their gardens.

    Anyway, onto energy matters. El Hierro appears less of a disaster this month and original posts although I suppose that is wind dependant? I’d have thought that if they can’t make renewables work here then nowhere. Have they much solar? – certainly Tenerife has a lot of hot water solar which has its own storage.

    Would (as Euan implies) El Hierro work significantly better with a ‘proper’ windpark ie better placed and more capacity? Perhaps coupled with some solar? I’m a bit worried about all the renewable investment to be honest although If they can make solar panels with 30 micron silicon wafers (instead of 200 microns and thus reducing embedded energy to half) at 30% efficiency then they may go well southern France onwards although mass storage obviously an issue.

    A small molten salt reactor would probably sort el Hierro out but that seems far off as well!

    • Joe Public says:

      ” sit as a concerned person worried about climate change but unsure whether I should be very worried”

      https://postimg.org/image/6240a4r03/

    • I would charge at least a dollar for that service 🙂

      Seriously though, I think the evidence is building that climate change is not the potential catastrophe that the media tell us it is. As you note, the models on which all future disaster scenarios are based show too much warming and there’s evidence to suggest that a couple of degrees of warming may in fact be beneficial. And as far as species extinction is concerned we have now had, according to some sources, over 180 years of global warming and still there is no single species which can be conclusively proven to have been driven extinct by its impacts.

      Expanding the size of the GdV wind farm would have two impacts – more curtailment of wind generation during high wind periods and no significant increase in wind generation during wind lulls (zero times two still equals zero). Adding solar would also not help. The problem is that there is nowhere near enough capacity in the reservoirs to store surplus energy for re-use during extended periods when the wind doesn’t blow and/or the sun doesn’t shine. And as discussed in previous posts there never will be.

      A small molten salt reactor would indeed sort El Hierro’s problems out but I would look into geothermal potential first.

      • Simon Cove says:

        Yes, ref extinction. I think the current rate is that it is running at the highest rate since the dinosaurs went extinct. No evidence of a single species extinction due to climate change that I know of, but masses due to habitat destruction and generally lots of humans. Most of our bread is made from wheat from only a few different strains. One bad virus/bacteria and we could be in a lot of trouble. Thankfully, Kew Gardens and other suppositories (with much sensible foresight) are storing tens of thousands of differing crop seeds. Hopefully, we won’t need them.

      • Simon Cove says:

        Meant to say good points otherwise ref the capacity. Sorry to be a pain but I assume the costs of this are far more than diesel alone and if carbon reductions are relevant which is complicated to say the least, does this save diesel or not? There may be other posts elsewhere I am missing so apologies if this is retreading old ground

        • Yes, indeed it does save diesel – according to the El Hierro Island Council it saved about 5,000 tonnes of it, valued at about $US 2.3 million on the current spot market, during 2015. But to generate this saving GdV was paid 12 million euros – over five times what the diesel saved was worth – under its power sales contract with the Spanish Government.

          You can also look at it in terms of emissions reductions. In its first year of full operation renewable energy from GdV lowered the island’s CO2 emissions by approximately 12,000 tonnes, but at a cost of around €1,000/ton.

          • Kees van der Pool says:

            Plus the cost of about 120,000m^3 of desalinized water.

          • gweberbv says:

            Roger,

            do we know for how many years GDV will get its 12 million euros paycheck? If I remember correctly, the construction costs were something like 80 millions. Even with huge O&M costs, the investment will be recovered after 10 years. What then? Will GDV generate profits of roughly 1000 Euro per El Hierro citizen ad infinitum?

    • Euan Mearns says:

      Simon, a good starting point is to consider the situation on El Hierro. Population of a few thousand. Power generation for decades provided by diesel generators. Why change this? It makes absolutely no difference whatsoever to global CO2 emissions to attempt to replace diesel with wind and pumped hydro on this island.

      The other argument is to save on the cost of diesel. But this argument is totally negated by the gigantic cost of the GdV scheme.

      From an engineering perspective, GdV NEVER had any prospect of providing 100% renewables for 100% of the time. They are currently running at 38% and now have two instead of one power generation systems – where is the environmental sense in that? And GdV and others still maintain this is a 100% renewable system even though it is demonstrably not. If you want to worry about something it should be fraudulent claims made by the pedlars of renewable energy. Those making claims are only interested in lining their own pockets. They don’t care about the welfare of society or the environment as a whole. It is a gigantic scam.

      The Canaries of course have a decent solar resource – almost in the tropics. Solar hot water sounds a much better idea to me since this is easily stored until you want to use it.

      The other RE resource we have discussed here is geothermal. We’ve been told it can’t work on the Canaries that comprise several active volcanoes. I can’t recall the reasons but am suspicious that those in charge may be averse to geothermal because it might actually work. But now I’m sounding paranoid.

      There is no sense in worrying about climate change since there is absolutely nothing you can do to stop it. Those who are leading the endeavour to decarbonise OECD economies are vain fools. All that will be achieved is the bankruptcy of our economic system and that represents a real and much larger threat than 400 ppm CO2.

      Earth’s climate belts are in a state of continuous flux. If you happen to live near the edge of one of those belts then you may well be experiencing climate change today. Some of it may be due to Man but more likely its natural. Where I live in NE Scotland I am on the northern edge of the temperate belt. Periodically, the climate changes and we are thrust into the southern edge of the Arctic zone with a period of about 1200 years. I am far more concerned about moving back into Arctic conditions than I am about becoming more central to the temperate belt.

      If you live in S California then your ancestors may have migrated there while it was Mediterranean. It is now shifting back to desert. Los Angeles has been built on the wrong place. There is absolutely NOTHING anyone can do to stop this process. The only sane response would be to migrate northwards.

      • Euan Mearns says:

        PS – sorry about my initial flippant reply. But I also have house guests this weekend and my time is spread a bit thin.

      • 1saveenergy says:

        “Where I live in NE Scotland I am on the northern edge of the temperate belt. Periodically, the climate changes and we are thrust into the southern edge of the Arctic zone with a period of about 1200 years.
        I am far more concerned about moving back into Arctic conditions than I am about becoming more central to the temperate belt.”

        Will you be the first climate migrant ?

        • Roger Andrews says:

          Florida is already full of climate refugees, but they’re escaping from the cold, not the heat.

          • Thinkstoomuch says:

            Some people around here resemble that comment. 🙂

            Then again in summer I am a traveling US Vagrant. 😉

            T2M

        • Euan Mearns says:

          The weather here really does get us down. It seems like we never get any summer. But we have selective memories. I definitely recall long hot summers as a youth growing up. But when you check the data we find that UK climate is not really changing that much. But we could become climate migrants. I kind of fancy the southern Alps.

    • Hi Simon,

      I suspect some solar would help somewhat but at great expense. I would think that a SMR combined with some wind and diesel would be best for islands like this, assuming cost was not an issue. In the Galapagos they worry about fuel spills. In their case, a SMR, some wind, and natural gas for everything else would be best, but Ecuador is a poor country. A handful of Caterpillar diesel generators is the cheapest option.

      I think wind has decent potential to be used in smaller amounts to reduce fuel bills for gas or diesel generators (the dog wagging the tail). Problems arise when they try to make the tail wag the dog, i.e., instead of using wind in smaller amounts acting as fuel reduction devices, they try to make wind the main source of power using gas or storage to stabilize it. With nuclear as baseload, you could end up with a low emissions system where the dog wags the tail. But economics usually favor fossil fuels, so, without some kind of endless subsidy, I don’t see fossil fuels being defeated in an open market, for what it’s worth.

  3. gah789 says:

    The management of the wind & hydro resources is simply bizarre. My interpretation of Figures 2 & 6 is that there is a minimum level of diesel output – roughly 1.5 MW – required for grid stability except during periods when they are confident that wind output will be sufficient to cover grid demand with a spare margin – eg Aug 1st and Aug 15-16th. However, there are extended periods when wind output is being used to pump water while diesel output is above the minimum level. What this means is that diesel is being to pump water, which is economic folly for an electricity system.

    I haven’t followed all of the discussion of El Hierro. I can only make sense of the way in which it is being managed on the assumption that there are some severe constraints on either (a) the level of the reservoir – eg for use for water supply – or (b) the way in which the hydro is able to operate. If correct, this is a long way from a project that offering an efficient combination of balancing wind and hydro.

    • Kees van der Pool says:

      Hi gah789,

      You wrote:
      “My interpretation of Figures 2 & 6 is that there is a minimum level of diesel output – roughly 1.5 MW – required for grid stability”.
      The minimum level of diesel output for grid stability is zero if there is water in the upper reservoir. There is about 11 MW available from the hydro generators within 5-10 seconds.

      You are right about diesel being used to pump water on 8/5&6, as Roger wrote. I think his guess about replenishing the reservoirs is right. Evaporation accounts for a loss of about 120,000 m^3 per year so it would be logical to see ‘pumping with diesel’ occasionally to replenish the top reservoir to an acceptable minimum level.

      Best,
      Kees.

      • You are right about diesel being used to pump water on 8/5&6, as Roger wrote.

        C’mon Kees, I never wrote that. In fact I’ve never seen any evidence that diesel has ever been used to pump water uphill at GdV. REE denies it, and I believe them.

        • Kees van der Pool says:

          Of course not. Let me rephrase: if they increase diesel while there is adequate windpower, they increase the amount of water being pumped around by increasing diesel power. There might have been a good reason, e.g. replenishing the top reservoir.

  4. gweberbv says:

    In the table the month July is missing in the 2016 data. Probably, because it was renames as August (and August is renamed as September).

  5. Kees van der Pool has just sent me some details on the response curve for Enercon turbines which I’ve superimposed on the Figure 4 XY plot:

    I’ll let Kees explain what it means 😉

    • Kees van der Pool says:

      !

      Red curve: wind generation if the windpark would be located at the airport.
      Black dots: actual value.

      Amplification due to altitude and location – with a price to pay due to turbulence, causing a huge dynamic range of power outputs as indicated by the spread and dots below the red curve.

  6. For what they are worth, here are some results from a brief review of airport wind measurements during August:

    During August wind directions were between WNW and ENE, with NNW being the dominant direction. Wind speeds increase gradually from 5m/s with the wind blowing from the ENE to over 7m/s with the wind blowing from the NW and WNW.

    I ran some XY plots of GdV wind generation against airport wind speeds for different wind directions but all of them still showed a large amount of scatter.

    • OpenSourceElectricity says:

      I can say, that these two wind turbines here: (Enercon 66, 1800kW) http://ais.badische-zeitung.de/piece/01/bf/e9/ec/29354476.jpg did not suffer any problems with turbulences in the last 13 years although they are in a similar topographic situation. So I do not yet see any cause to assume that turbulences are the cause for lower power generation than expectable from Airport windspeed in el Hierro.
      My guess is they are still unsing the whole system for academic test operation of various kinds. And they still don’t like to use the hydro-system for the tasks for which it was built. So far it’S a wind-diesel hybrid system, and not a wind – hydro-diesel Hybrid system, beside a few days of testing.

      • sod says:

        I fully agree with your analysis.

        This data obviously shows a hydro test, as the hydro test starts before the wind is lost:

        https://s15.postimg.io/nc7m8unob/temp.png

        If turbulences were a problem, we would see more of this. But it happens rarely and simply always looks like a test.

      • Kees van der Pool says:

        Open Source, you wrote: “So I do not yet see any cause to assume that turbulences are the cause for lower power generation than expectable from Airport windspeed in el Hierro”.

        I suggest you look a lot harder before making gratuitous, “off the wall” statements like that.

        According to Eric Breckwoldt, ENERCON Sales Director for Spain & Portugal:

        “In day-to-day operation, however, the WECs run at limited capacity because the variable power output triggers fluctuations of frequency and voltage in the grid that need to be compensated constantly.

        The island location presented some special logistical challenges – all components had to be shipped to the island harbour – and the wind conditions at the site also created problems for the project planners.

        In summer, the winds along the west coast of El Hierro are extremely strong, often with heavy turbulence. So the planners opted for the E-70 wind turbine on a 64-metre tubular steel tower. “This sturdy wind turbine is the ideal solution for this type of site,“ says Eric Breckwoldt. In addition, the E-70 wind turbines were equipped with a blade load control system that has been used successfully in the E-82 model”.

        BTW, “a similar topographic situation” in Baden-Württemberg? You are joking, right?

  7. My
    Modelling of wind and pumped-storage power
    https://scottishscientist.wordpress.com/2015/04/03/scientific-computer-modelling-of-wind-pumped-storage-hydro/

    recommends

    store energy = 1.11 days x peak demand power
    annual maximum wind power = 5.5 x peak demand power

    Assuming El Hierro peak demand is 7.6MW
    http://euanmearns.com/el-hierro-renewable-energy-project-september-2015-performance-review/

    Put the 7.6MW peak demand into my recommendation equations

    store energy = 1.11 days x 7.6MW = 8.436 MW-days = 202.5 MWh = 729 gigajoules

    Assuming the head between the 2 reservoirs to be 655 metres, the volume of reservoir required is

    volume = mass / density
    volume = energy / (g x head x density)
    volume = 729,000,000,000 / (9.81 x 655 x 1000)
    volume = 113,500 m3

    So the GdV reservoirs seem to be big enough and no change to the reservoirs is required.

    Now let”s find the recommended annual maximum wind power

    annual maximum wind power = 5.5 x 7.6MW = 41.8MW

    whereas only 11.5 MW of nameplate capacity is installed

    I’m not sure what the annual peak wind power is now (8MW is the maximum MW plotted in figure 4) so let’s assume that 8MW is the annual peak wind power now.

    Now – needed — factor increase compared to existing
    8MW – 41.8MW – 41.8/8 = 5.2 times more wind power needs to be installed, to a total nameplate capacity of 5.2 x 11.5 = 59.8GW

    Executive conclusion.

    The El Hierro GdV wind turbines are under-powered by a factor of 5 compared to what will be needed for a successful system design to achieve 24/7/52 100% renewable on demand power.

    The recommendation is that additional wind turbines be installed to a total capacity of 60GW.

    • Kees van der Pool says:

      Scottish: by your numbers, the upper reservoir @ 115,000m^3 would be filled in about four hours, of course after upgrading the pumps to roughly 50MW. The pumps will then be needed full time to waste wind energy for the balance of the windy months. And when the wind stops. . . . . . .

      I think you may want to look at your model a bit more.

      • @Kees van der Pool

        Actually, my number

        “volume = 113,500 m3”

        was NOT a number that dictated, suggested or implied any change WHATSOVER to the power of the pumps at El Hierro GdV.

        So, no! “upgrading the pumps to roughly 50MW” is a ridiculous suggestion!

        The modelling I had done in 2015 assumed that the power of the pumps was equal to the peak demand power.

        Although the pumps at El Hierro GdV are only 6MW

        http://euanmearns.com/el-hierro-renewable-energy-project-september-2015-performance-review/

        which is less than the peak demand of 7.6MW, this smaller pumping power than I had modelled is not so much smaller to be very significant.

        The very significant design problem at El Hierro GdV is with the wind power which is a factor of 5.2 too small.

        I am not proposing any change whatsoever to the pumping power at this stage. First things first and the priority change must be to install 60MW of nameplate wind turbine capacity.

        Instead of
        “1. An 11.5MW wind farm with five 2.3MW Enercon E-70 wind turbines.”
        the design perhaps could have specified

        “1. A 59.8 MW wind farm with twenty-six 2.3MW Enercon E-70 wind turbines.”

        So the system is suffering a performance disappointment because it is missing 26 – 5 = 21 wind wind turbines of the same size.

        Certainly in the windy months, with such a modified system there will plenty of surplus wind energy available.

        The choice for the system designer then is either to curtail surplus generation or perhaps to consider installing power-to-gas equipment to use the surplus wind power to generate hydrogen gas via electrolysis of water.

        A more complicated model (which I have not had the time to model) would calculate the expectations of using such a power-to-gas options to fill a 2nd tier (inexpensive but inefficient) energy store (a store of hydrogen gas) to use to generate electricity from when the 1st tier pumped-storage hydro store is empty.

        If you want to look at a more complicated model – on you go – I do not have enough time, sorry.

        • Kees van der Pool says:

          Fair enough, Scottish, we’ll keep it simple.

          you wrote: “First things first and the priority change must be to install 60MW of nameplate wind turbine capacity”

          and

          “So, no! “upgrading the pumps to roughly 50MW” is a ridiculous suggestion!”

          Would you agree that in that case the newly planted windfarm’s 60GW output would have to be curtailed to say 8MW? This all the current pumping capacity can handle.

          • OK keep considering the simple system with no use of surplus wind power for power-to-gas etc and so curtailment must be used.

            No I would not agree to your “8MW” figure.

            The wind farm must be able to serve El Hierro customer demand AND the GvD pumps at the same time.

            Curtailment kicks in once those 2 requirements for power are satisfied and how much those 2 total at any instant depends on how much demand there is and whether the pumps are needing power or not.

            Peak El Hierro customer demand is 7.6MW
            GvD pumps maximum is 6MW

            So the wind farm should be capable of powering as much as 7.6+6 = 13.6MW

            60GW is the total nameplate capacity of the wind turbines only. That number is of most use when specifying how many wind turbines to install.

            41.8MW is the annual maximum wind power which would not supplied for the simple system we are considering because curtailment would have to kick in.

            I’ve really got no idea where you get “8MW” from?

            It might help you to have a look at the line graphs of power grid and energy store timeline on my blog post –

            “Modelling of wind and pumped-storage power”
            https://scottishscientist.wordpress.com/2015/04/03/scientific-computer-modelling-of-wind-pumped-storage-hydro/

          • Correction GdV not “GvD”!

          • Kees van der Pool says:

            Scottish, you wrote:
            “So the wind farm should be capable of powering as much as 7.6+6 = 13.6MW”

            Which is a far cry from your 60 MW. You would still be in trouble, though, when demand drops to the nighttime value of 4.5MW (sometimes as low as 2.5MW, as happened on 7/20). This means an excess of 3MW that cannot be dissipated. The line voltage would go up and circuit breakers would kick in all over the island: blackout.

            The current windfarm has a nameplate capacity of 11.5MW. For operational reasons (turbulence) Enercon curtailed the output to 8MW.
            Even at that rating, the upper reservoir (capacity 350,000m^3) would have been filled up about three times over in July. There is not nearly that much water in the system so it is being pumped around most of the time.
            Increasing windpower would simply increase the volume of water being pumped around without doing any useful work.

            Best,
            Kees.

          • I “would still be in trouble”?

            I think not.

            Firstly, I am sticking to my guns.

            My recommendation is for 60MW nameplate wind turbine capacity and for not one MW less!

            If anyone is in trouble it is GdV who are in trouble with environmentalists campaigning for countries to ditch fossil fuels because of all the bad publicity following GdV’s failure to meet the aims of the project because GdV have grossly under-powered their wind generation by a factor of 5!

            “Islands Trying To Use 100% Green Energy Failed, Went Back To Diesel”
            http://dailycaller.com/2016/03/18/islands-trying-to-use-100-green-energy-failed-went-back-to-diesel/

            A successful system design must use automatic signalling to control curtailment automatically.

            The pumps should NEVER be used to dissipate energy.

            The function of the pumps is to raise the level of water in the upper reservoir, to store energy – to do useful work only.

            When there is no need to raise the level of water in the upper reservoir to store energy, the pumps should be OFF.

            Therefore the minimum power requirement situation is with

            pumps off – 0MW
            minimum demand – 2.5MW
            in which case the power from the wind turbines must be curtailed to 0+2.5 = 2.5MW.

            And yes that’s a 60MW nameplate capacity wind farm that may have to be curtailed to 2.5MW automatically in a howling gale.

            Turbulence may be caused by too close spacing of turbines.

            15 rotor diameters should be spacing enough but the 5 turbines already installed look to be spaced closer than 15 rotor diameters.

            Also it is not a good idea to have all your turbines in one straight line – a great big circle is best.

            If the turbines are all in a line then when the wind blows in the direction of the line then power output will suffer a lot.

            Obviously there are a lot of smaller mistakes that GdV have made but next to their GIANT BLUNDER of not installing enough wind generation capacity, all their smaller mistakes pale into relative insignificance, though no mistake should ever be repeated ideally.

          • Kees van der Pool says:

            Scottish, you wrote:
            “And yes that’s a 60MW nameplate capacity wind farm that may have to be curtailed to 2.5MW automatically in a howling gale”

            According to the Enercon E-70/2.3MW power curve, 2.5MW (100KW/windmill) would be happening at between 4m/s and 5m/s windspeed at the windfarm. From Roger’s graph, this would translate to about 2m/s to 3m/s at the airport, hardly howling.

            Thanks for your interesting comments.
            Kees.

          • The Calculated power curve of the ENERCON E-70
            http://www.enercon.de/fileadmin/Redakteur/Produkte/e-70/LK_E-70_2300kW_en.png

            applies only WITHOUT ANY curtailment WHATSOEVER and this curve must NOT apply when curtailment is signalled.

            An automatic curtailment system should be designed to be able to change the power curve characteristics of a wind turbine dynamically, according to the curtailment signals.

            In which case, when the wind speed is 25m/s and the grid’s automatic curtailment control is signalling to a wind turbine to curtail its power output to only say, 100kW, then absolutely not 1kW more than 100kW should be supplied to the grid and certainly not the “2,300kW” which is plotted for 25m/s in the linked to power curve which I repeat, should only apply when there is no curtailment.

          • Kees van der Pool says:

            Well, if that curve does not apply, what do you think the output of a windfarm with 26ea Enercon E-70/2.3MW windmills would be at 4-5m/s windspeed?

          • The curve you linked to applies if there is no curtailment.

            When there is a wind farm which has a satisfactory system for automatic curtailment then the curve you linked to would still apply but in PART ONLY for the lower wind speeds, when the power output would anyway be less than the curtailment being demanded by the grid control system.

            Supposing there is curtailment in operation and 100kW was the curtailment level that was signalled to a wind turbine then for wind speeds lower than 4 to 5 m/s, there would be not any difference in power output, but for higher wind speeds the output would be curtailed to only 100kW.

            I have created an image, modifying the power curve diagram to show 2 new example power curves, which should apply dynamically whenever the combined wind turbine with curtailment receives the appropriate signal, for example

            Signal 1. to curtail power output to no more than 100kW
            Signal 2. to curtail power output to no more than 1600kW.

            https://scottishscientist.wordpress.com/wind-turbine_curtailed/

            You can see from my power curves that the new lines only change the power curve characteristics for the higher wind speeds where otherwise the power output would normally, without curtailment, be higher than the curtailment power limit that was being signalled by the grid system control.

            This reference mentions signalling of curtailment so someone out there is familiar with the concept.

            http://www.nrel.gov/docs/fy14osti/60983.pdf
            “4.2.1 Signaling of Curtailment”

          • Kees van der Pool says:

            Scottish, you wrote:
            “to curtail power output to no more than 1600kW.”
            Where do you think the rest of the power goes if the wind picks up?

          • The power output of a wind turbine can be CONTROLLED – in particular is easily REDUCED by the turbine’s control system varying the pitch of the rotor blades to make the rotors less efficient at generating power from the wind.

            https://en.wikipedia.org/wiki/Blade_pitch#Wind_turbines
            http://xn--drmstrre-64ad.dk/wp-content/wind/miller/windpower%20web/en/tour/wtrb/powerreg.htm

            So then “if the wind picks up” and the turbine’s power output is thus moderated, the “rest of the power” remains in the wind.

            So that’s the advantage of being able to signal curtailment automatically. Since there is never any excess power generated from the wind in the first place, there is never any need to dissipate power.

            Simple.

          • Kees van der Pool says:

            Simple indeed!
            You wrote earlier:”So the wind farm should be capable of powering as much as 7.6+6 = 13.6MW”. Which means that for the 60MW windfarm you suggested, the “rest of the power” remains in the wind.
            I don’t think GdV will haul another 20 Enercons uphill any time soon.

          • Greg Kaan says:

            They’ll need to extend the ridge to form a circle too.

            Could also make another reservoir from that if the ridge was to loop back to close an existing point.

          • Kees van der Pool says:

            🙂

      • Euan Mearns says:

        But I thought we had decided the upper reservoir was broken?

    • gweberbv says:

      60 MW wind farm? When already the production of the existing 10-plus-something MW wind farm is often curtailed? Are you kidding?

      What about a 15 MW of PV instead? Cheaper to build than the existing wind farm, much chepaer to operate and much better utilization of the hydro storage. And less variations than wind. I hope the people in charge think about this option once they have to pay the first bills for bigger repairs of the wind turbines.

      • 60MW nameplate wind farm yes and I have posted above in my comment the method above whereby I arrived at that “60MW” number which was derived from the general recommendation from my blog post –

        “Modelling of wind and pumped-storage power”
        https://scottishscientist.wordpress.com/2015/04/03/scientific-computer-modelling-of-wind-pumped-storage-hydro/

        which speaks for itself, scientifically, with no kidding nor hand-waving statements.

        My recommendation is

        “store energy = 1.11 days x peak demand power
        annual maximum wind power = 5.5 x peak demand power”

        for a simple wind and pumped-storage power system.

        Admittedly, a more complex system mixing wind power and PV solar panels with pumped-storage hydro would be definitely worth thinking about (and modelling) for somewhere sunny like the Canary Islands – and yes it may indeed work out cheaper than installing another 21 x 2.3MW wind turbines.

        • Greg Kaan says:

          I’m puzzled by your “annual maximum wind power” requirement. Is this level of overbuild to cater for marginal wind conditions so that non-generation (no wind doesn’t care how many turbines are installed) periods are minimal?

          I would have thought that it would be better to install more turbines that have a lower cut in speed rather than more of the same E-70’s.

          • I might suggest studying the power grid & energy storage time line graphs on my blog post, such as this one.

            https://scottishscientist.files.wordpress.com/2015/04/windpumpedstorage_june.jpg

            In particular study the demand time curve (coloured red) in relation to the wind power time curve (coloured grey) and note the critical significance of when wind power is less than demand power because at those times the hydro turbine generation time curve (coloured green) is non-zero indicating that the turbines are generating power to make up the short fall in the wind power.

            You might be able to appreciate that with a smaller overbuild factor the grey line would be below the red line more often meaning the turbines would be asked to produce power more often, meaning that the store would run empty, causing a power shortage.

            So it’s not “non generation periods” (below cut-in wind speed) but rather LOW generation periods (just above the cut-in speed) that are critically improved by increasing the “overbuild” factor.

            Installing 21 more of the same E-70s would be possible and doing so would make the critical difference towards a successful system design.

            Therefore a firm recommendation for executive action on that basis can now be made.

            Whilst other options of wind turbines would be possible to consider, it would be wind turbines that offer SIGNIFICANTLY MORE POWER at wind speeds JUST ABOVE the E-70s cut-in speed which would offer improved performance as a substitute.

            (However, wind turbines that only offered a little power at a LOWER CUT-IN WIND SPEED compared to the E-70s cut-in wind speed but which did NOT offer significantly more power just above the E-70s cut-in wind speed would not really be much of an improvement, if any.)

            Possibly other wind turbines might work out better but that would really take a lot of research work first (that I don’t have time to do) before arriving at a firm recommendation for executive action.

            My recommendation of adding 21 x E-70s would fix GdV’s blunder, guaranteed.

            The system may not be perfect after +21 x E-70s but perfecting it from there will be trivial.

      • Kees van der Pool says:

        Hi gweberbv.

        Agreed. El Hierro’s latitude & weather is perfect for solar. Its predictable, easily scaleable and I think you wrote some months ago that all necessary parts can be FedExed. Much better than random wind and it would avoid the discussions/criticisms about the perceived performance of the windmills as a function of the windspeed at the airport.

        I guess Enercon did a better selling job than the PV people.

        Now, if a solution could be found for the hopelessly inadequate storage reservoirs. . . . . .

        Best,
        Kees.

    • REVISION

      My
      “Modelling of wind and pumped-storage power”
      https://scottishscientist.wordpress.com/2015/04/03/scientific-computer-modelling-of-wind-pumped-storage-hydro/

      has recently been revised after my previous recommendation was successfully challenged by modelling of very low wind conditions prevailing in September 2014.

      The revised recommendation is –

      • store energy = 1.5 days x peak demand power
      • annual maximum wind power = 7 x peak demand power

      Assuming El Hierro peak demand is 7.6MW
      http://euanmearns.com/el-hierro-renewable-energy-project-september-2015-performance-review/

      Put the 7.6MW peak demand into my recommendation equations

      store energy = 1.5 days x 7.6MW = 11.4 MW-days = 273.6 MWh = 985 gigajoules

      Assuming the head between the 2 reservoirs to be 655 metres, the volume of reservoir required is

      volume = mass / density
      volume = energy / (g x head x density)
      volume = 985,000,000,000 / (9.81 x 655 x 1000)
      volume = 153,300 m3

      So the GdV reservoirs, specified as “a useful capacity of 150,000 m3”, seem to be approximately at the recommended capacity.

      Now let’s find the recommended annual maximum wind power

      annual maximum wind power = 7 x 7.6MW = 53.2MW

      whereas only 11.5 MW of nameplate capacity is installed

      I’m not sure what the annual peak wind power is now (8MW is the maximum MW plotted in figure 4) so let’s assume that 8MW is the annual peak wind power now.

      Now – needed — factor increase compared to existing
      8MW – 53.2MW – 53.2/8 = 6.65 times more wind power needs to be installed, to a total nameplate capacity of 6.65 x 11.5 = 76.5MW

      Executive conclusion.

      The El Hierro GdV wind turbines are under-powered by a factor of about 7 compared to what will be needed for a successful system design to achieve 24/7/52 100% renewable on demand power.

      The recommendation is that additional wind turbines be installed to a total capacity of about 80GW.

      So instead of
      “1. An 11.5MW wind farm with five 2.3MW Enercon E-70 wind turbines.”

      the design perhaps could have specified

      “1. A 78.2 MW wind farm with thirty-four 2.3MW Enercon E-70 wind turbines.”

      So the system is suffering a performance disappointment because it is missing 34 – 5 = 29 wind wind turbines of the same size.

      This is not to recommend the 2.3MW Enercon E-70 for the required wind power upgrade but simply to give an indication of the factor by which the initial design was under-powered.

      • Edit
        “to a total capacity of about 80MW.”

          • My question for you is this Roger.

            Assuming the same “September 2015” winds which you modelled to produce figures 7, 8 and 9.

            Consider these options if you would please

            Storage as per the current design AND
            Wind farm capacity increased by certain multipliers, “M” several times greater than M = 2 or doubling – maybe M = 6, 7, 8, 9, …

            What is the minimum value of “M”, to the nearest whole number, for which the hydro does NOT run out during the September 2015 period modelled?

          • SS: Here are the numbers you requested.

            I can fill demand during October 2015 with a 100MW wind farm, i.e. 8.7 times bigger than the existing 11.5MW installation, and with the existing 250MWh of reservoir storage. The 8.7 number is low because it ignores the low-wind periods that preceded and followed October. If I included these it could easily double.

            Here are the stats for October, a low-wind month, based on the wind times 8.7 scenario:

            Total wind generation: 6,127 MWh
            Wind generation used: 3,627 MWh
            Wind generation curtailed: 2,500 MWh
            Percent curtailment: 41%

            Now here are the stats for July 2016, a high-wind month:

            Total wind generation: 37,275 MWh
            Wind generation used: 3,623 MWh
            Wind generation curtailed: 33,653 MWh
            Percent curtailment: 90%

            I think these results speak for themselves.

          • “I can fill demand during October 2015 with a 100MW wind farm, i.e. 8.7 times bigger than the existing 11.5MW installation, and with the existing 250MWh of reservoir storage.”
            ____

            OK, thanks for those numbers Roger.

            I would note that “8.7” is within the range “maybe M = 6, 7, 8, 9, …” for “times bigger than the existing 11.5MW installation” which I had suggested.

            Now I have a follow up question for you please.

            Supposing you do model a longer time period, this time not ignoring but rather INCLUDING the low-wind periods that preceded and followed October.

            What then would be the resultant approximate numbers, in MW, in “times bigger”, required to fill demand?

          • Roger, I have a follow up question for you please.

            I am questioning your earlier assertion, on September 28, 2016 at 9:53 pm –

            “If I included these it could easily double.” – Roger Andrews

            – because I don’t think M could so easily double. I doubt that M= 2 x 8.7 = 17.4 is a good estimate for the minimum value of M required to fill demand but I am happy to be proved wrong by the numbers speaking for themselves.

            So instead of you guessing, I am asking you to do some more modelling and once again allow the numbers to speak for themselves, if you would please.

            Here’s my follow up question for you again …

            Supposing you DO ACTUALLY model a longer time period, this time NOT ignoring but rather INCLUDING the low-wind periods that preceded and followed October.

            What then would be the resultant approximate numbers, in MW, in “times bigger”, required to fill demand?

            If it is not convenient at this time or of interest to you to answer my follow up question, fair enough.

            I am not sure if you are ignoring my follow up question or if you didn’t notice that I had asked a follow up question?

          • SS. No, I’m not ignoring your question. It just involves a lot more work than I have time to do at the moment.

            I also don’t see the point of doing it. No one in his right mind is going to install 100MW – or 150MW or maybe even 200MW – of wind capacity to service a 7MW peak load. There’s also the question of where to put all the extra turbines. Check out Google Earth.

  8. Correction MW not “GW”!

    • Roger Andrews says:

      I think it’s time for me to put in my ten cents’ worth.

      The performance of the Enercon turbines is a side issue. At the risk of repeating myself, the big problem is that GdV’s reservoir storage capacity is about twenty times too small to allow the system to perform its intended function of storing surplus wind power generated during high-wind periods for re-use during low-wind periods, which is why there’s so much wind curtailment. This has been discussed in numerous previous posts, with graphical examples of the impacts provided in Figures 7, 8 and 9 of the January-February update, accessible through the El Hierro Portal.

  9. Rainer says:

    Please put this post also in the http://euanmearns.com/el-hierro-portal/
    Thank you

  10. Rainer says:

    REE only:
    Start: 2016-09-11 00:30
    Stop: 2016-09-12 00:30

    My calculation:
    REE only all together since 2015-08-01:
    493 h
    still under 5% working time …….

    Source REE calculacion by Roger:
    38,7% REE of electrcity demand all together
    65.9% REE in July 2016

    Press release of GDV 9 de agosto de 2016:
    http://www.goronadelviento.es/index.php?accion=articulo&IdArticulo=177&IdSeccion=89
    1:1 in local newspaper:
    http://elhierrobimbache.com/index.php?option=com_content&view=article&id=4324:la-central-hidroeolica-de-el-hierro-acelera-y-situa-a-las-renovables-a-la-cabeza&catid=9&Itemid=868

    Extracts of the press release:
    GDV calculation by Google translator:

    “Renewable were the largest source of electricity on the island of Meridiano during last July, with 67% coverage of demand, compared with 33% derived from diesel generation. The positive data from the Central hydro-wind developments are known today, August 9, coinciding with the first anniversary of the technical milestone that led to El Hierro to stay one hour only clean sources, on August 9, 2015.”

    “”It is the combination of two sources which allows the power supply provided by the Central hydro-wind is stable and with the same guarantees of safety and quality supply any diesel engine, so we could get to cover 100% of demand on numerous occasions, “says CEO Gorona wind, Juan Pedro Sanchez.”

    “100% of the whole year is still a long-term goal, but Gorona Wind, a company formed by the Cabildo (majority shareholder), Endesa, the Technological Institute of the Canary Islands and the Autonomous Government, will not stop working on it. “Meanwhile, the Central hydro-wind is a system that can cover between 70% and 80% of the annual electricity demand of El Hierro and the known data today point to a good evolution that soon we will reach that average, with significant results environmental, technical and economic “says Sanchez.”

    My comment:
    GDV still owns very interesting human “calcuradoras”.
    In public school it really will not be a 100 points by the teacher…..

  11. Rainer says:

    REE only
    2016-09-28 06:20

  12. Rainer says:

    Diesel on again:
    2016-09-29 06:50

Comments are closed.