El Hierro, or “Isla del Meridiano”, is the smallest, most isolated body of land of those which comprise the Canary Islands. It has a population of approximately 10,162, and this month met 100% of its citizens’ energy needs for four hours straight by using an innovative renewable resource called the Gorona del Viento plant. The Gorona del Viento was implemented at the end of June, and by July and August, it was able to provide approximately half of the island’s energy needs. Indeed, El Hierro is officially no longer completely reliant on diesel supplies from Tenerife, a larger Canary Island that lies 200 km away.
The plant cost €82 million (£58.2m). Its system is unique because the wind and water components work in tandem. It consists of five wind turbines with a total capacity of 11.5MW and two water reservoirs. One lies 700m above sea level, the other is located by the coast, at sea level. The two reservoirs are connected by two 3km-long pipes. Water runs down to the lower reservoir from the upper reservoir and necessarily passes through a series of water turbines, thereby generating electricity. The Gorona del Viento uses fresh water rather than sea water in order to make sure that the aquifers are not contaminated in case of leaks. It is said that the facility is expected to reduce 18,700 tones of carbon emissions per year.
Juan Gil, Gorona del Viento’s chief engineer, explained: “When we get enough wind from the wind farm, we produce electricity and distribute it through the grid. Whatever is left, we use it to pump water from the lower reservoir to the higher one, and then, when the wind drops, we let that water fall through a set of hydraulic turbines and we generate electricity again for the population.”
It is windy 80% of the time on the island, but wind power supply ultimately cannot be taken for granted. However, the system seems to be overcoming this issue, because the water in the upper reservoir can be released “within milliseconds” when the wind isn’t very strong. The system is said to continuously switch between releasing water from the upper reservoir and pumping water back upwards, depending on how strong the wind is, and whether more electricity is needed.
Juan Pedro Sanchez, an industrial engineer who advises on the Gorona del Viento project, claims that the amount of time that the plant will be able to be used at a time will steadily increase. He believes that soon, it will be possible to leverage the plant for weeks on end to supply 100% of the island’s electricity needs. He added: “I think that in a year or so, the plant could supply all the electricity the island needs for about 200, 250 days.”
Thomas Padron, one of the project’s founders, has pointed out that this very well may be possible, but first, the capacity of the water reservoirs needs to be increased so that more backup hydro energy is available when there is no wind. Indeed, the length of time that Gorona del Viento can generate power is proportional to the amount of water in the lower reservoir at any given time. As soon as the lower reservoir is full, the plant operations must cease for a time, because fresh water is already in short supply.
The length of time Gorona del Viento can continue generating hydro power is determined by the volume of the sea-level reservoir. As soon as the lower reservoir is full, hydro generation has to stop. This is because fresh water, which is in short supply on El Hierro, cannot simply be released into the sea.
El Hierro’s current council president, Belen Allende, has estimated that the island will save the central Spanish government about €80M over the next 20 years. Allende added that the Spanish government will most likely give the island €5-7M per year.
Of course, there will always be dissenting opinions around any issue. Some argue that the cost of building the facility – already €82M – reflects the fact that electricity is ultimately very expensive, and that long-term costs won’t be mitigated. Others feel that the money spent on developing the plant could have been used to invest in the island’s tourism industry, which is currently non-existent.
However, most of the islanders approve of the plant, because they remember how the island was almost completely neglected by Spanish authorities in the 1970’s. Indeed, it suffered many power outages, especially when conditions at sea were bad. Droughts have also been an issue, because there are no bodies of fresh water on the island. Padron commented accordingly: “El Hierro suffered many droughts and people were forced to emigrate to the bigger neighbouring islands, and to Cuba, Argentina and Venezuela.” Currently, there are three desalination plants in operation on the island that pump fresh water to villages at higher altitudes, and use up half of the island’s electricity in the process. Padron concluded that if the island were able to completely control its own electricity supply, it would increasingly be able to control its own water supply as well.
The island may be isolated and windy, but these factors contribute to its undeniably rugged charm, as does the night sky which is said to be completely free of light pollution. Indeed, El Hierro seems to be a perfect location for those who enjoy peacefulness and solitude. Moreover, it is an incredibly safe island, and it is said that people even leave the keys in their car ignitions.