Industry Market Trends

El Hierro -- How an Island Can Serve as a Model for Renewable Energy

Jul 18, 2011

El Hierro, the most remote of Spain's Canary Islands, is on track in 2011 to complete an important step in its transition to energy sustainability. The island's government expects to go live shortly with a combination wind and hydroelectric facility that will generate nearly all of the island's power from renewable sources. (Photo: Coastline, El Hierro. Credit: ezioman, CC BY 2.0)

The El Hierro effort illustrates the value of islands as test cases for the development of energy-self-sufficiency in communities, and as proving grounds for renewable-energy technologies.

Historically, the island has generated electricity with diesel fuel shipped in by tanker. Now wind and solar farms will generate the island's power, with excess power stored via a pumped-storage hydroelectric facility. The hydro plant will use excess electricity to pump water uphill into a 556,000-cubic-meter-capacity reservoir, where it can be released later to drive turbine generators. The reservoir is built in the crater of an extinct volcano.

Map showing Canaries and El Hierro

El Hierro, with land area of 276 square kilometers (107 square miles) and a population of about 11,000, attracts tourist trade drawn to its beautiful coastlines, mountains, and landscapes, along with archaeological sites and artifacts dating back to the pre-hispanic era. UNESCO has designated the island a Biosphere Reserve. The island's windy heights make it a good candidate for wind power generation, and its clear skies for solar energy. (Maps: El Hierro, Canary Islands shown off the coast of Africa. Credit: OpenStreetMap, CC-BY-SA)

Smart Technologies Integrate Wind and Hydro Power

Gorona del Viento El Hierro, a local company on the island, is handling the overall construction and engineering for the combined renewables project. The company has contracted the Spanish Elecnor Group to design and develop the hydro-wind turbine plant and bring it into service. Elecnor says that, as a result of the initiative,

... the island will no longer require its annual consumption of 6,000 tonnes of diesel (40,000 barrels of imported oil), and it will reduce its emissions of CO2 into the atmosphere by 18,700 tonnes every year.

Illustration of El Hierro's hydroelectric station

(Illustration: Combined wind-hydro power station. Courtesy of Gorona del Viento El Hierro. For access to a larger version of this image, click here.)

ABB Group, a Swiss-based power and automation systems firm hired in turn by Elecnor to build the electrification and control systems for the hydro plant, says El Hierro's 11.5 megawatt (MW) five-turbine wind farm and 11.3 MW hydro plant will provide 80 percent of the island's energy needs, with the remaining 20 percent generated through solar thermal collectors and grid-connected photovoltaic systems. (See ABB's announcement, "The world's first renewable energy island.")

ABB representative Antonio Ligi tells me that, after commissioning of the wind-hydro facility, El Hierro will continue to generate the remaining 20 percent of its energy needs with the existing diesel power station for an interim period while the solar systems are under development.

ABB says its contribution to the project "comprises a new interconnection substation, equipped with UniGear and UniMix medium voltage switchgear, which will receive the power generated by the five wind turbines and the hydropower turbines, and deliver it to the island's main substation via distributed transformers and a Relion REB 670 intelligent protection system."

El Hierro pumped-storage reservoirOne of the great challenges of integrating renewable energy sources into electric grids is managing their inherently uneven production of electricity -- the wind only blows when it blows, and the sun only shines when it shines, but the utility needs to be able to match generation fairly closely with demand, within certain tolerances. (Photo: Pumped-storage reservoir on El Hierro. Credit: Mataparda, CC BY 2.0)

ABB's announcement shows how the company's systems help mitigate that problem in the case of El Hierro:

An important challenge for ABB was the installation of Automatic Generation Control (AGC), which maintains stable plant frequency and voltage by sharing active and reactive power demand in the generators and tie-lines. This is done in a way that allows the working points of the generator sets to operate with as much margin as possible, so that the plant can withstand bigger disturbances.

A distributed control system (DCS) "will control the four hydropower turbines, the pumped storage process, the new interconnection substation and the existing substation, and communicate with the new wind farm." Describing how things work from a system perspective, ABB says,

By communicating with the wind farm, the ABB control solution will automatically start releasing water from the upper reservoir to generate power at the hydroelectric plant whenever the wind power generated is insufficient to meet demand. Conversely, excess wind power will be used to pump water to the upper reservoir, for use when wind power is low.

According to Andrés Cala, writing for the New York Times, Gorona del Viento El Hierro is a consortium 60 percent owned by the island's government, 30 percent by Spanish utility company Endesa, and 10 percent by the Canary Institute of Technology. The €65 million ($87 million) project is partly funded by a €35 million European Union government grant. El Hierro plans to reinvest the expected €4 million yearly in profits from the venture to develop solar heating and electric-vehicle systems.

Islands: Important Test Cases for Renewable Energy

Despite ABB's headline and other write-ups I found on the El Hierro project (e.g., "The world's first renewable energy island"), El Hierro is not the first island to position itself as all-renewable.

For example, the Danish island of Samsø, with a population of 4,000, began the conversion to all-renewables in 1998, and now generates all of its electricity from wind power and 75 percent of its heat from solar and biomass. (See Wind-Works' article "Samsø: Denmark's Renewable Energy Island" and Elizabeth Kolbert's 2008 New Yorker article, "The Island in the Wind.")

El Hierro wind farmOf course, El Hierro ups the ante in that its population is more than twice that of Samsø. In one other important respect, though, El Hierro appears distinctive. A study by Siti Fauziah says that unlike Samsø's, El Hierro's electric grid is independent and unconnected to any other system: "[The island] is totally isolated, as the significant sea depths make any interconnection impossible." She writes that diesel generators will remain in place on the island for emergencies. (Illustration: El Hierro Wind Farm. Courtesy of Gorona del Viento El Hierro)

The El Hierro initiative is serving as a model for renewable-energy projects in other isolated communities. ABB says that the Greek island of Icaria is modeling its own hydro-wind project on El Hierro's. According to a brochure from the Canary Institute of Technology, similar projects are under consideration on the islands of Crete and Madeira.

In a 2009 BBC program, Gonzalo Piernavieja, research and development director for the Canary Institute of Technology, maintains that

Islands can play a very important role as pioneers of the energy revolution... We think we are pioneering part of this coming energy revolution in the sense that islands are aiming at energy self-sufficiency. The model of having an island with a hundred percent -- or a high percentage of renewable energy penetration -- can be replicated in lots of islands worldwide...

The island as a whole can serve as an experiment not only for this particular energy combination, but also for other types of energy-related issues like mobility, like efficient transport solutions... Examples like El Hierro will prove technologically that this is possible.

Peter Sweatman, CEO of investment-consulting firm Climate Strategy, tells Cala of the New York Times that

El Hierro is an emblematic project. It's really a role model for other islands, and for non-islands it's a test case to fully develop the potential for pump storage.

Eduard Sala de Vedruna, research director for the Europe Wind Energy Advisory Group of IHS Emerging Energy Research (IHS EER), also believes El Hierro is an important test case. He tells Cala,

It's very positive to the power industry to have a renewable energy storage system running. El Hierro is going to be replicable in other islands first and as the system improves its application will expand to other systems. Many clichés about renewable energy will be broken once this is proven, as costs fall and large-scale application increases.

Pueblo of El Pinar on El Hierro

(Photo: Town of El Pinar on El Hierro. Credit: Mataparda, CC BY 2.0)