Wind + pumped hydro on El Hierro a failed experiment 

The island of El Hierro, situated in Spain’s Canary Islands off the northwestern coast of Africa, has unwittingly become the pilot project for renewable power. But this pilot project hasn’t come close to achieving its aims. Any other communities looking to shift their energy grid to wind power should critically study what happened in El Hierro and take it as a failed experiment that should never be repeated.

El Hierro, the smallest of the Canary Islands, is only 12 miles wide and has long sought to become self-sufficient. Beginning on June 27, 2014, the island introduced a hydro-wind facility, Gorona del Viento (“wind power plant”), to provide about half of the island’s electricity needs. The facility’s five wind turbines produce 11.5 MW (megawatts) of power, able to supply, part of the time, electricity for the island’s 11,700 residents, additional tourists, and three water desalination facilities.

When wind power is insufficient—for instance, when the wind speed is too low or too high (at which time, the blades must be feathered or they will break)—a hybrid system is used so that hydro power can generate electricity by water flowing from an upper to a lower reservoir and turning hydraulic turbines. Thus, the system constantly switches between wind and hydro power depending on the strength of the wind and electricity demands.

Back in 2014, anticipation was high for the project to supply all of the island’s power. Juan Pedro Sanchez, an industrial engineer who works as an adviser to Gorona del Viento, said that “I think that in a year or so, the plant could supply all the electricity the island needs for about 200, 250 days.” However, the facility has never been able to provide even half the island’s electricity overall, and the longest period during which the hydro-wind facility has been able to fully power the island has been only 28 consecutive days. And as can be seen on the plant’s official website, their hours of 100% renewable energy provided by the hydro-wind system has been decreasing, with 1,328 hours provided in 2021 (there are 8,760 hours in a year, or 8,784 in a leap year), 1,008 hours in 2022, and 413 hours in 2023 (more recent data was not provided). The amount of diesel not consumed as a result of the power plant has shown a similar decrease, with 6,040 tons in 2021, 5,981 tons in 2022, and 4,509 tons in 2023.

Francis Menton, retired commercial litigation lawyer and the author of the Manhattan Contrarian blog, has written several articles on El Hierro. In 2015, he had determined that the project was already failing in its attempt to provide 100% hydro-wind electricity for the island. He wrote that “since only about one-quarter of El Hierro’s final energy consumption is electricity, the project has replaced barely 10% of El Hierro’s fossil fuel consumption.”

Moreover, diesel plants constantly need to be kept online as backup in emergency situations or when the hydro-wind facility is insufficient for the island’s electricity needs. He said that in order to get rid of diesel backup, “El Hierro would need a pumped-storage reservoir some 40 times the size of the one it had built,” which is not at all feasible. The island plans to build a solar power plant to increase green energy capacity to supposedly reach 100% of demand in the next 14 years. But solar works poorly on cloudy days, and not at all at night, so this will only partially solve the pumped-storage reservoir problem.

This issue is compounded by the fact that the lower reservoir is currently less than 40% the size of the upper reservoir, which further limits the effective capacity of the water storage system. If the lower reservoir were enlarged to match the upper reservoir’s size, we would see a slight increase in the fraction of electricity able to be generated by the hydro-wind system, but it would still be hopelessly insufficient.

Yet, El Hierro is a near-perfect site for a pumped-storage hydro facility, with a steep, extinct volcano containing a large crater at the top where water can be stored. But despite this, it is nowhere near adequate to provide the entire island’s power. About 58% of the island is a protected national area, and the total population of the island is only about 1% that of a major American city. This is a humbling consideration when looking at our own society: if it can’t work for such a small island, what hope is there for a similar system to power cities or even countries of hundreds of millions of people with much higher electricity demands?

In engineer Roger Andrews’ article on El Hierro, he wrote that, although Gorona del Viento is cutting El Hierro’s imported diesel bill approximately in half, saving them about a million euros a year, the cost of the hydro-wind facility is 64.7 million euros (as estimated by Gorona del Viento) and up to 82 million euros (as estimated by other sources). This means that the capital costs would amount to 5,600-7,000 euros per installed kW, which is about the same costs for a nuclear plant that operates at a far higher capacity factor. The capacity factor is a measure of how often a power plant operates at its maximum potential output over a given time period. As a comparison, the typical capacity factor of a nuclear plant is around 82% worldwide, while, for the El Hierro plant, it is only 15%.

Andrews ultimately concludes that “Staying with fossil fuel generation would be simpler and cheaper.” Regardless, the time it would take to pay back the project would obviously then be 64.7 to 82 years, not accounting for plant operating costs. But long before then, the wind turbines would be too old to operate and so would have to be replaced, increasing the overall project cost even further.

Fortunately, fossil fuels are able to reliably provide our power at a reasonable cost, and, with modern technology, cleanly without toxic emissions as well. But climate activists want us to believe that we need to eliminate fossil fuel use to “fix” the climate by reducing CO₂ emissions. So, like so many of their other hairbrained energy schemes, the origin of El Hierro’s energy experiment is in itself misguided.

Let’s take El Hierro’s example as a costly mistake that should not be repeated, much less so in a society of millions that relies on consistent electricity rather than an isolated island focused almost exclusively on conservation.

[See also:  Eigg, Scotland, King Island, Tasmania]