Chira-Soria – Another Flawed Renewables Project

To the east of the Canary island of El Hierro, where the Gorona del Viento wind-pumped hydro project has attracted international attention, the island of Gran Canaria is developing a wind-solar-pumped hydro project of its own that has so far attracted very little attention outside Gran Canaria. This is surprising because the project is many times larger than Gorona de Viento and has one distinguishing feature that so far as I know makes it unique. The €300 million pumped hydro storage plant is scheduled to be constructed first. The wind farms and PV panels will come later.

Why is the pumped hydro plant being built first?

According to Antonio Morales, President of the Gran Canaria Island Council, because A massive implantation of renewables is necessary to achieve energy sovereignty. Chira-Soria, whose dams will act as a battery that stores wind and solar energy and transforms it into a continuous and stable electricity supply, is the key.

According to the Red Eléctrica de España, because It represents essential infrastructure for integration of renewables on the island.

And according to a resolution recently passed by the Gran Canaria Island Council, because It will allow Gran Canaria to obtain up to 70% of its energy production from renewables.

This innovative approach looks good on paper but makes sense only if Chira-Soria has sufficient storage to handle a “massive implantation of renewables” and in particular up to 70% renewables generation, which in the case of Gran Canaria (population 840,000) works out to about 2.8 terawatt-hours a year. Here we look briefly into the question of whether it does.

First some details on the Chira-Soria pumped hydro plant. It will connect the existing Chira and Soria fresh water reservoirs as shown in the graphic below:

Figure 1: The Chira-Soria pumped hydro system

Plant specifics are:

  • Chira (upper reservoir): Volume 5.2 million cubic meters, maximum elevation 903.5 meters
  • Soria (lower reservoir): Volume 32.8 million cubic meters, maximum elevation 620m
  • Head at maximum elevation: 283.5 meters
  • Generation/pumping capacity: 200 megawatts
  • Efficiency after generation and pumping losses: 68%
  • Storage capacity: approximately 5,000 megawatt-hours (limited to the capacity of the smaller Chira reservoir).

5,000MWh of storage capacity will, however, be available only when Chira is at its full 5.2 million cubic meter capacity, and according to the graphic from this link reproduced below as Figure 2 it will rarely if ever be at that level (the brown curve shows reservoir volume before irrigation water extraction and the blue curve what’s left over). The link further concludes that only half of the total capacity of the Chira reservoir, i.e. 2.6 million cubic meters, could be used for pumped hydro because of irrigation extraction, evaporation losses and other constraints. If so then the effective storage capacity of the Chira-Soria plant decreases to 2,500MWh:

Figure 2: Predicted variations in water storage volume with time, Chira Reservoir

Next some details on Gran Canaria electricity supply and demand. Data for the year 2011 from the Local Energy Management Agency of Las Palmas of Gran Canaria are summarized in Table 1:

In 2011 Gran Canaria generated 93% of its electricity from thermal plants (a mixture of CCGTs, gas turbines, steam turbines and diesel units) and 7% from renewables, most of it wind. Renewables generation would therefore have to be scaled up by a factor of ten from 2011 levels to achieve the 70% penetration the Island Council expects.

Is Chira-Soria capable of supporting 70% renewables generation year-round ? I didn’t have the time to perform a full evaluation so I picked a single day at random (October 19, 2015, which was the last day for which complete data were available at the time I did the work. I believe this will qualify as a random selection). Figure 3 shows Gran Canaria’s demand curve for the day (data from Red Eléctrica de España) with the wind and solar generation curves plotted below. Solar contributed about what it would be expected to contribute but wind generation was at or close to zero for most of the day. This, however, is a common occurrence during September and October, which are typically low-wind months in the Canaries:

Figure 3: Gran Canaria demand, wind and solar generation, October 19, 2015.

Eyeball estimates indicate about 10,000MWh of total demand offset by about 100MWh of renewables generation, and factoring up renewables generation by ten to analog a 70% renewables scenario still leaves a deficit of about 9,000MWh. Clearly Chira-Soria is not large enough to supply Gran Canaria demand even for one windless day. And low-wind periods in the Canaries can go on for weeks at this time of the year.

Although this is not to say that Chira-Soria is worthless. It does have the capacity to follow demand to the point where Gran Canaria’s thermal plants could have run continuously at around 410MW while maintaining the reservoirs in balance, as illustrated in Figure 4. (The pumping and generation cycles each represent about 1,000MWh). But this benefits only the thermal plants, which are ultimately scheduled to be replaced in their entirety by renewables. The benefits will also be at least partially offset by the 32% loss incurred in cycling power through the hydro plant:

Figure 4: Hydro pumping and generation needed to maintain thermal generation constant at 410MW, Gran Canaria, October 19, 2015

So how much storage is needed to balance 70% renewables generation on Gran Canaria? I have no specific estimates for Gran Canaria, but scaling up “windless period” estimates from the Gorona del Viento plant on El Hierro yields numbers in the hundreds of GWh range, two orders of magnitude larger than the storage capacity of Chira-Soria. There are other reservoirs on Gran Canaria with pumped hydro potential but there is no way anything like this amount of storage could ever be developed on the island.

In summary, Chira-Soria emerges as yet another example of an ambitious renewable energy project that has no realistic chance of working simply because no one involved in the planning process seems to have realized – or is willing to admit – that it’s impossible to install the huge amount of energy storage needed to make it work. Moreover, the project is still being justified by the alleged success of the €84 million Gorona del Viento wind-hydro plant on El Hierro, which as will be discussed in the October performance update is beginning to fray at the edges after only four months of operation.

With Chira-Soria Gran Canaria is heading down the same blind alley as El Hierro, although potentially a far more costly one. Up to €300 million is already allocated for the pumped hydro facility, and expanding existing wind and solar capacity by a factor of ten or more will raise costs to well over a billion – if wind and solar ever expand to that level, that is. Crunch time will come when Chira-Soria comes on line and its storage limitations become apparent. Will wind and solar construction grind to a halt at that point, or will it continue regardless? The only thing we can be certain of is that Gran Canaria’s fossil-fuel plants will be keeping the lights on for a long time yet.

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20 Responses to Chira-Soria – Another Flawed Renewables Project

  1. Willem Post says:


    Mark my words. Only a few of the thermal plants MAY be decommissioned after many years have gone by. What a colossal failure it will turn out to be.

    I bet some politically connected construction outfits will be making big money on it and saying, it is not our fault, as we built it according to the specs and drawings.

    Why not send your analysis to Red Eléctrica de España, etc.

    It reminds me of the boondoggle of Spain’s 50 MW CSP plants.

    • Roger Andrews says:

      Willem: I mark your words. But the chickens won’t come home to roost on this one for another five or ten years, and by then old guys like you and me may well have lost interest. And the young guys who are still around will probably have forgotten what the original purpose of the project was, human memories being as short as they are.

  2. Euan Mearns says:

    Are the Spanish engineers idiots? I doubt it. This therefore boils down to deception and perhaps corruption. But I wonder who is being deceived? Is EU money involved again Roger?

    • roberto says:


      you could ask the same question about the German, or Dutch, or UK, or Italian engineers…

      I’ve come up with my own answer to your question: it’s all about ideology… and when ideology is concerned even rational minds like scientists and engineers go bezerk.

      Only time will make things clear… but by then the green spin machine will have found some scapegoat to point to as the only responsible for the colossal failure that the whole green energy program will turn out to be.

      I take bets, no kidding.

      Cheers, and keep up with the good work… this blog is priceless.

      • I agree with Roberto that ideology can be powerful. Before my current job in the UK steel industry, I worked with ECN. There, we were scaling up a process for a particular compound.

        I discovered that the invention were were using was performing far better in a similar process where the product was the same family i.e. slightly longer chain. For us it made little difference on the size of market as our goal was to sell the technology rights over. So go for your best performance even if its market was smaller or even niche. First steps.

        However ideology got in the way, wanting a grand success. They are still trying.

    • Roger Andrews says:

      Euan: I don’t know what the financing arrangements are for C-S but the EU recently forked out 34 million euros to fund a semi-submersible offshore wind farm on Gran Canaria.

      Spain – FloCan5 – Wind power (EUR 34 Mln)

      The project is a floating offshore wind farm consisting of five 5 MW wind turbines with a total capacity of 25 MW with floating moored foundations, internal grid and grid connection to an onshore substation. The foundation is a semi-submersible concrete construction. The project is expected to be located at 1.5–3.7 km from the south-eastern coast off the island of Gran Canaria, in water depths of between 30 and 300 m.

      I agree that the Spanish engineers aren’t idiots. I can’t say what it boils down to but a lot of politicking went on before REE took the project over from Endesa.

  3. Hugh Sharman says:

    Roger, what is the MW capacity of the turbines? I searched the article very briefly (I fear) but could not find! Will get back with better considered thoughts later!

  4. A C Osborn says:

    Isn’t it a sad state of affairs and a very poor reflection on human nature that if Roger actually sent this analysis to the Spanish Authority responsible, that it would make no difference even if they understood and believed it.
    It would be like sending the same kind of report to Swansea City about the up coming “Lagoon”, it is a total waste of money and will produce electricity costing 3 times as much as Gas & Coal.
    But the thing is it will put Swansea “on the map”, they are doing their bit to save the world.
    Swansea is known for little other than it’s Premiership Football Club, this will bring them to the World’s attention. The fact that in the future they will be a total laughing stock at having built one of the most expensive white elephants in the UK does not strike them at all.
    I fear it is the same with all these grand schemes, they are famous for a short time, they are doing their bit, the waste of Tax Payer’s money just doesn’t enter in to their thinking.
    It is religion.

    Ask youself why would the “Engineers” care they are getting paid, probably very well and will just move on to the next mad scheme once this one is finished.

  5. Hugh Sharman says:

    Thanks Roger!

    Mea culpa!

    It is not often that I even dare disagree with the main thrust of your argument. But in the case of Las Canarias, you do not seem at all to have taken into account the enormous vulnerability of these remote, highly populated islands, hundreds of km off the west coast of the Sahara Desert, all separated by deep water that makes inter-connection impossible, to the vagaries of imported liquid hydrocarbon prices and security of supply.

    Furthermore, the strong winds are more or less constant for 9 months of the year and sunshine is the main reason that they are so heavily populated.

    If ever there was a strong case for making use of the sun and wind to reduce hydrocarbon dependence, that case exists on Las Canarias!

    I am rushing out to a birthday breakfast right now but may expand on this these later!

    Toot toot!

  6. Günter Weber says:

    The hydro plant will make a lot of sense to shift a certain portion of the daily solar production to the evening/night. One should just forget about the wind for a moment and instead build something like 750 to 1000 MW of PV (will cost roughly 1 billion euro). On a sunny day, PV can then cover something like 60% of the demand of 24 hours.

    From the topography it looks like both reservoirs could be made much bigger. This might make the plant useful also for storing wind production.

    In any case I doubt that the 70% statement made by politicians (not stating, what kind of ‘energética’ is meant) has any close connection to technical specifications of the hydro plant.

  7. Certainly trade winds and a lot of sun make the case of Canary islands one of the best for the attempts to go to wind+solar options, if any. However, if this is for the reason of the huge dependency of Canary islands of the fossil fueled supplies, then what we would do is to change the dependency of fossil fuels from solar+wind dependency, which is not produced there neither and will never reach the autonomy to produce all the parts to integrate locally a wind generator or a solar PV plant.

    I have worked several years with Spanish institutions on these projects, specially in a similar attempt of El Hierro, that was analyzed in La Palma (85,000 inhabitants about ten times more than El Hierro) and 708 km2.

    The project in Gran Canaria, if done with the 100 MW of solar, as suggested by Günter Weber, would require a space occupation of about 30 km2 of well placed, well tilted, well oriented modules in an island with 1,560 Km2 (a 0.2% of the territory; not negligible now for an island with national parks and very populated)

    Wind projects could yield a lot of energy because the trade winds in that zone of hte Atlantic, but the ocean platform goes down very sharply. Floating turbines are not well developed and have extra costs and difficulties.

    Onshore platforms have a huge visual impact and there is a lot of opposition from people and organizations living from tourism (from 2.1 million inhabitants in the archipelago, about 400,000 live from tourism, where in the past, lived much more on their own with bananas, potatoes, tomatoes, cereals and local cattle). We all know that long range tourism (10.6 million tourist/year in long haul flights, with about one week stay in average) is absolutely unsustainable, but in all my conferences and presentations there, there were also fights among different kind of environmentalists: some supporting renewables at any cost (!?), some others supporting more natural spaces, but keeping tourism (!?). I have found the same contradiction between tourism and renewables when lecturing in the Baleares archipelago and explaining and warning on the limits of renewables and the problem of peak oil and the lack of sustainability of tourism as a source of income. Nobody wanted lo listen my words.

    The most impressive case is Lanzarote island, one of the most desertic ones closed to the Sahara (846 Km2 and 140,000 inhabitants. About fifty years ago, about 4,000 people lived there and all of them had cisterns or tanks to collect the few rainwater (61 mm/year). But they were quite sustainable, even they washed once a week with a washbowl. Had some cereal potatoes, and grapes well cared in holes practiced to concentrate moist and rain water.

    Today, the 140,000 inhabitants of Lanzarote, plus the 1.82 million tourist visiting them (one week average stay, equivalent to 35,000 permanent inhabitants) demand plenty of fresh water. Authorities are proud of the tourist records every coming year. We talked with the authorities on the potential sustainability problems. today, there are plenty of hotels, with swimming pools saunas, showers, etc. Basically today 100% of water comes from a desalinated plant. This plant is electrically powered by a Generating plant. In its turn, the plant is served with fuel oil, brought in a tanker from the Tenerife refinery. If one day any of the links of this chain breaks, the whole island will collapse in a question of days.

    No easy way out for the archipelagos. No esay way out for most of us, living in a consumerist level.

    • Pedro: One thing I’ve never understood about the Canary Islands is why they are concentrating on wind and to a lesser extent solar. The islands are in a tectonic environment very similar to Iceland and the Azores and have active volcanoes, hot springs and anomalously high thermal gradients. So why aren’t they looking into geothermal?

    • Hugh Sharman says:

      Great posting Pedro!

      You are right! The economies of these islands are ludicrously unsustainable and oil dependent. As already mentioned, this is one more place in the world where from a strategic and logistical view point, RE makes ample sense!

      I am aware that there is a successful, dedicated wind to RO desalination plant on Gran Canaria. I will try and get the details and post them here.

      Why is that not being done, at scale, on all the islands?

    • Euan Mearns says:

      The Canaries are not really like Iceland that is a hot spot on a mid ocean ridge. They are more like Hawaii, hot spot on abyssal plain. The last big eruption was on Lanzarote, you can still see glowing rocks at the centre of the fissure. And Tiede on Tenerife is still active – puffs of steam coming out the top last time I was there 2 years ago.

      The whole business model is of course linked to oil. Should oil run scarce and get too expensive then CO2 emissions from leccy production will be the last of the island’s worries.

      But they will also need to be careful with deploying RE everywhere. Tourists go there to enjoy the wild natural beauty.

  8. We also talked on the geothermal potential during my stay in La Palma invited by El Cabildo (regional government), together with people form Unelco (the electric operator, quite opposed to renewables, because the difficulties of integrating intermittent, stocastic sources in a limited isolated network), the Ministry of Industry, professors of the Las Palmas university with a lot of experience in the area and some other experts. One of the things to show tourists in Lanzarote is how to make a bush spontaneously burn by introducing it into a hole of a couple of meter deep, in some areas. So, every one should think on the enormous potential, Iceland like, in the Canary Islands, due to this excellent temperature gradient, but to my surprise, the regional authorities told me that they have tried many times with experts from several countries (Germany among them) and they did not find them suitable. That’s why we were invited. (By the way, I would recommend this La Palma island, the most beautiful and less exploited one, with quite a lot of rainwater and forests and still some valuable agricultures in small farms).

    Euan is right, the marine platform is abyssal and offshore wind will be very costly. They have recently been touched by a couple of abnormal, tough small hurricanes from the Atlantic, that raised the issue of how corroded were the high and medium tension electric network steel columns.

    Solar has not spread, because there is little land to be taken to this purpose. Rooftop installations are generally speaking very poor in terms of efficiency, because the existing housings were not originally thought for solar and the roofs are not well oriented or tilted or receiving shadow form other buildings or trees, sometimes by the mountains around in sunrise and7or sunset. On the ground multimegawatt installations are usually lacking adequate space, which has not been taken by urban constructions, cultivated land or national parks. My environmentalist friends living there, were sad, because what it used to be a paradise, now has been sealed by a layer of concrete, asphalt, bricks, glass, iron, etc. from the shores to sometimes as high as 800 m. over the sea level in all island’s peripheries, for urban constructions, mostly devoted to tourism, thus covering what one day were the most fertile lands in the archipelago. I was invited by one of them who still breeds Canary cows, a special strong and well adapted species. He was very angry and protested because they were expropiating his lands for the extension of the Los Rodeos airport in Tenerife. This fighter was making demonstrations with his beautiful cows by plowing with them the rich lands close to the civil worlks extending the airport.

    The water problem is huge. They had since several centuries, aqueducts collecting water from the gorges in a very intelligent form and they even had a hige tunnel networking bringing underground water to the population and some fields. today, desalination is taking over and many of these water structures are absolutely stressed i most of the islands (exception of El Hierro and La Palma)

    There is a difficult, very difficult way back. In my opinion, they should start, as soon as they can, breaking up all the concret, asphalt and so and try to recover the fertile land and come back to the preindustrial stage. But of course, nobody wants even to hear about that and probably at this stage of civilization, they could hardly feed the 2.1 millions in the islands.

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