A small island in the Atlantic is showing how energy storage can be used to help run on 100% renewable energy.
To get to El Hierro, in the southwest tip of the Canary Islands, you first need to fly to the provincial capital of Santa Cruz, in Tenerife, halfway along the island chain. There, a surprising sight currently greets visitors.
Alongside the cargo boats and cruise ships in the town’s busy port lie three hulking drill rigs.
The massive structures await the start of an oil prospection project green-lighted by Spain’s Minister for Energy, Trade and Tourism, Jose Manuel Soria, in the waters between Morocco and Fuerteventura in the eastern Canaries.
Soria’s steamroller approval of the project, with an OK being granted in principle even before the closing date for objections, has angered Canary Islanders.
The potential for oil extraction
They see the potential for offshore oil extraction as a threat to tourism, the main source of income for the islands.
“They’re probably here because if they were in Fuerteventura people would set fire to them,” says Olivier Bello, who works at Tenerife’s La Laguna University, nodding towards the drill rigs.
The islanders have good reason to feel concerned. After all, in El Hierro, less than 30 minutes flight time by prop plane from Santa Cruz, they are showing how there could be another, more sustainable energy economy.
On June 27 the Herreños, as El Hierro’s locals are called, proudly inaugurated Gorona del Viento, a pioneering energy project that they hope will soon allow them to dispense with fossil fuels altogether.
The concept is simple: a wind farm near the capital, Valverde, powers the island and drives pumps that take fresh water from a reservoir just above sea level to another in a higher volcanic crater, connected via 530 metres of pipes.
When the wind dies, water from the top reservoir is allowed to flow back down to the lower one, driving hydro turbines that provide power instead.
But if the idea of combining wind power with pumped hydro storage is far from cutting edge, that is because the origins of Gorona del Viento go back to a time when there really was not much else in terms of renewable technology.
El Hierro has long been something of a special case within the Canaries. A lack of sandy beaches, along with limited flat land for airport construction, meant it was pretty much off limits when tourism arrived to the other Canary Islands in the 1980s.
Even today, El Hierro’s short airstrip, inaugurated a decade and a half ago, can only take the twin-prop craft operated by the local Canary Island airline Binter.
Cut off from the rest of the world, El Hierro remains relatively untainted by the get-rich-quick brand of speculation that has turned pristine natural enclaves into tacky tourism hotspots on many other Canary Islands.
Watching this transition, El Hierro’s residents became determined not to let go of what little natural value their island had to offer.
“El Hierro missed out on the tourism boom and we needed to look for other selling points, like sustainability,” explains Cristina Morales Clavijo, who handles communications for Gorona del Viento.
Ambitious environmental projects
That is why the island began a series of ambitious environmental projects back in the 1980s.
As well as designating 58% of the island’s landmass as protected areas, the Herreños created a marine reserve that extends across a good portion of the island’s southernmost tip, and today attracts divers from across Europe.
And then there was Gorona del Viento. The fact that wind resource is abundant on the island is clear from the minute you arrive. El Hierro’s emblem, in fact, is a juniper tree whose trunk is curved back to the ground from the force of the wind.
Before Gorona del Viento, however, little use had been made of this resource. The only wind turbine to have been installed prior to the project, an aging Vestas machine, now stands idle on a hillock above Valverde.
Instead, the island’s 10,100 or so inhabitants have relied on a diesel-based generating plant owned and operated by Endesa, the Enel subsidiary that is one of Spain’s big five electricity companies.
Growing energy needs
The plant, near the port of Puerto de La Estaca, has just about been able to keep pace with El Hierro’s slowly growing energy needs. Endesa added a new genset about two years ago, bringing the total capacity up to about 12MW.
Even so, blackouts are a fairly common occurrence and in some more remote locations the power is routinely cut off at night to save energy. Plus it is expensive. And that is a problem not just for energy consumers, but water users, too.
Although El Hierro gets more rainfall than the easterly Canary Island tourist destinations such as Fuerteventura and Lanzarote, it still relies on three desalination plants for its water supply.
And that water, produced at sea level, has to be pumped up considerable heights to be used for irrigation. Even though the island is has an area of less than 280 km2, at its highest point it rears 1.5 km above sea level.
Desalination and pumping together account for between 45% and 50% of total energy consumption on the island, says Morales. It was this tremendous cost that led Endesa to look at renewable energy alternatives.
In fact, Gorona del Viento was originally conceived mainly as a way to pump fresh water up to a high-altitude reservoir, from where it could be distributed across the island. It’s potential as a power supply came almost as an afterthought.
Even in the final plan, water distribution is still a primary concern. The uppermost reservoir, holding 380,000m3 of water, is oversized so that it will deliver irrigation when the lower pool is full.
The thought of combining water and energy management has been hatching for a long time in El Hierro. Unelco, a local utility later bought out by Endesa, came up with the idea in the 1980s.
In the 1990s the Instituto Tecnológico de Canarias (ITC, for Canary Island Technology Institute) came on board.
And Gorona del Viento, a joint venture between the island council or Cabildo (with a 60% share), Endesa (with 30%) and the ITC (with 10%), was not created until 2004.
Construction finally started in 2009, after the Institute for Energy Diversification and Savings (Instituto para la Diversificación y Ahorro Energético in Spanish) put a €35m grant towards the total project cost of €82m.
Even with funding in place, however, and community consensus on the location of the wind farm, with good wind resource not far from the existing Vestas machine, the original plan suffered a number of significant changes.
The pipes connecting the two reservoirs, for example, had to be routed underground for 530 metres to avoid a site of community interest highlighted as part of an exhaustive environmental impact assessment.
And to import the five 2.3MW E-70 Enercon turbines that make up the wind farm, the Spanish authorities had to set up a temporary customs office in El Hierro so the machines would not have to be routed via Tenerife.
Even then there were logistical problems to put the turbines in place. Because the direct route to the wind farm from Puerto de La Estaca winds through Valverde, the machines had to be transported right across the island.
Finally, the lower reservoir was downsized to 150,000m3 after engineers discovered the volcanic pumice stone substrate, which crunches like popcorn under the wheels of a car, lacked the strength to hold the larger volume first planned.
Best-of-breed engineering brands
Despite, or perhaps thanks to, its long gestation, Gorona del Viento today boasts a number of best-of-breed engineering brands.
Besides the Enercon machines, which are deliberately medium-sized to ensure the failure of one will not knock out too much generating capacity, Gorona del Viento uses Andritz Hydro water turbines and Flowserve pumping units.
The control systems, meanwhile, are proprietary. Touring the plant’s control centre, Morales cautions against photographing any screens until the software has been patented. It all works, though, she assures.
At its inauguration, the plant was completely operational.
Hydro generation kicks in within five seconds of a lull in the wind, but the system is highly dynamic, with each wind turbine being adjusted independently to maintain overall stability.
Not taking chances
Even so, the Spanish grid operator Red Eléctrica de España is not taking any chances. At the time of writing it was allowing Gorona del Viento to start feeding into the island grid in 100kW increments, testing each step of the way.
Morales could not say when the plant would be feeding into the grid at full capacity. At that point, though, the capacity of the lower reservoir should be enough to cover the island’s electricity needs for four days using hydro alone.
Taking into account wind patterns on the island, that should be enough to replace 80% of current diesel generation, representing a €80m saving over 20 years.
The saving will be split between Gorona del Viento’s shareholders, since the price of electricity, which is regulated by law in Spain, will stay the same to end users.
However, the Cabildo is planning to use the money for further energy and water-related projects. One of them is to try to get Gorona del Viento to cover fully 100% of the island’s energy needs.
How El Hierro will go fully renewable
Taking care of four-fifths of El Hierro’s total energy consumption with renewable energy is already a major achievement.
It will save 6,000 tons of diesel, equivalent to 40,000 barrels of oil that would have to be brought to the island by tanker, at a cost of €1.8m a year.
It will also avoid the equivalent of 18,700 tons of carbon dioxide in emissions, the same as planting a forest of up to 12,000 hectares or 20,000 football fields in size, not to mention 100 tons a year of sulphur dioxide and 400 tons of nitrous oxide.
But Gorona del Viento is convinced it can go even further, using a two-pronged strategy. The first part of the plan is to use renewable energy more intelligently when the wind is blowing.
Currently there is no demand response built into energy consumption on the island. Electricity use, including the heavy draw of irrigation pumps and desalination plants in El Tamaduste, El Golfo and La Restinga, is purely on demand.
Cutting demand in times of calm
However, Gorona del Viento’s backers are aware that cutting demand in times of calm, when the turbines are no longer spinning, could help the island’s hydro reserves last for longer.
That in turn means timing energy-intensive processes for times when there is plenty of surplus power, for example at night. On a smaller scale, it might also be possible to get islanders to participate in demand response programmes.
One of the things that could help is that the whole of Spain is currently going through a European Union-mandated smart grid upgrade programme that is seeing intelligent meters being installed across the country.
The exact level of ‘intelligence’ inherent in the meters is open to some debate. Observers have commented, for example, that many meters only read energy flows in one direction.
Useless for distributed energy integration
That effectively makes them useless for distributed renewable energy integration and net-balance self-consumption of power, which is not allowed in Spain anyway.
Nevertheless, with Endesa both controlling the rollout of smart meters in El Hierro and acting as a major shareholder in the Gorona del Viento project, there is still hope the two concepts could be linked in some way to help renewable generation go further.
Even with some smart demand-response juggling, however, it is unlikely Gorona del Viento could get to cover El Hierro’s energy needs year-round. For that, the Gorona partners are hoping another form of energy storage might come into play.
Currently the number of electric cars on Spanish roads is microscopic. As in other countries, getting people to buy into electric vehicles is difficult for a variety of reasons.
One of them, undoubtedly, is the fear of running out of juice after a couple of hundred kilometres. But that’s hardly likely to happen in El Hierro.
Stocking up on power
The trip from Valverde in the northeast corner of the island to the Faro de Orchilla lighthouse on the southwest tip is a mere 46 kilometres.
And stocking up on power from Gorona del Viento’s wind power reserves is sure to be cheaper and easier than buying petrol from one of the island’s three service stations.
In fact, the distances on the island are so small that the average electric vehicle would probably carry plenty of excess power stored in its battery at any time.
So, the thinking goes, islanders might not mind some of this going back into the energy system when the wind drops.
Electric vehicle battery storage, the merits of which are so hotly debated in other renewable energy markets, might actually make a lot of sense in El Hierro. Seven electric vehicle recharging points are already planned for the island.
Converting vehicles to electric
There are hopes that up to 70% of the island’s vehicle fleet could be converted to electric in eight years.
Then, Enercon calculations show, the combination of wind, pumped hydro, demand response and battery storage could indeed cover 100% of El Hierro’s energy needs. Of course, there are a lot of big ‘ifs’ involved.
The potential for using consumer-owned electric vehicle battery storage is particularly shaky, given that other utilities have already turned their backs on the idea. But then again, the Herreños may have more than just a passing interest in playing ball.
It is no overstatement to say that Gorona del Viento is one of the biggest things that has ever happened to the island. The project has attracted worldwide attention and acclaim.
The Independent claims El Hierro “may soon be one of the most progressive places to live on the planet” thanks to the scheme. The Hungarian media billed it as “the greenest island in the world.”
Calling card for the world
Alpidio Armas, president of both Gorona del Viento and the island Cabildo, says: “The hydroelectric plant is one of our calling cards for the rest of the world.
“The interest that this project sparks in the media is just another example of the relevance of our project for the international community, which is working to reduce polluting gases and is evermore conscious of the importance of environmental care.”
The project has also snapped up a number of awards.
“These are all opportunities not just to add prestige to a project supported by the international scientific community, but also to promote the El Hierro brand as a world-leading sustainability lab,” trumpets Gorona del Viento in its press pack.
And the company is determined to make the most of this attention. The islanders backing the scheme have too long watched tourism’s bounty being shared out among the other Canary Island communities. Now their chance has come.
Commercialising skills elsewhere
Gorona del Viento may have been set up as construction business to get a single project off the ground, but having got this far the company is determined to commercialise its skills elsewhere.
It is already in conversations with other Canary Island councils, including neighbouring La Gomera, which has a similar mountainous terrain and small population.
There is also interest from other island groups, such as the Azores just a short flight away in the Atlantic and Indonesia almost half a world away, according to Gorona del Viento’s Cristina Morales.
The hope is that the work undertaken in El Hierro can be used as a template for similar projects elsewhere, giving work to a new generation of engineers and other skilled personnel growing up on the island.
It sounds ambitious, but perhaps no more so than the lengths Spain’s other renewable energy interests have had to go through recently.
Companies such as Abengoa and Gamesa have had to make their way abroad as the Government backed down on earlier promises of lavish support for renewable technology, leaving Spain’s renewable energy market bereft of potential.
A similar story
A similar story is now playing out on a smaller scale in the Canary Islands, with central government politicians paying lip service to renewables while doing all they can to sustain the carbon economy.
This month Soria, Spain’s Canary Island-born Trade and Energy Minister, touted increased support for the island’s renewable energy projects in the form of a 7.5% ‘reasonable return’ on investments.
But this is exactly the same level that was granted to mainland projects formerly eligible for much more generous feed-in tariffs. And there has been widespread condemnation of the way the return is calculated.
Meanwhile the same minister has lost no time in granting Canary Island oil prospection drilling rights to Repsol, a private company which has curiously shown a penchant for hiring former energy mandarins into top executive posts in the past.
Even Repsol was alarmed when Soria started claiming oil extraction could create up to €400m a year for the Canaries, however. The Minister more recently said some wealth would trickle down, but could not say how much.
Paulino Rivera, president of the Canary Islands, responds: “Look at Nigeria, look at Mexico, look at Venezuela, Argentina, Equatorial Guinea, and see if oil means wealth for the people or wealth for the few.”
He could have added: “Look at El Hierro. That’s the future.”
Written by Jason Deign