Technology

It was expected that construction of the wind farm would be completed – depending on any difficulties encountered precisely due to the wind – within a week. “It's an exciting time,” comments Alpidio Armas, President of the company. “The sight of wind turbines in situ shows that the island is about to make a qualitative leap.” The Hierro Hydrowind Project located in Valverde, will contribute to the island becoming energy self-sufficient through the synergistic use of two energy sources: wind and hydropower. The project takes advantage of two natural conditions on the island, a volcanic crater that is used as a reservoir and the winds that lash the island. Basically, the idea is to use wind power generated by wind turbines to pump water up to the crater of the extinct volcano, and then use falling water to generate power using hydroelectric turbines.

With the wind farm under construction (11.5 MW), one of the main elements of the plant is beginning to take shape, albeit almost two years late. The supplier of the five wind turbines is the German manufacturer Enercon. “This is the first multi-megawatt wind turbines in the Canaries, since the power rating of each one is 2.3 MW, while none in the archipelago have more than a megawatt of power,” Gorona del Viento explained in a statement. “The type of work and the significance of this project for the whole island have made this a moment of maximum expectation,” says the company, an entity established by the Canary Islands Government or Cabildo Insular (60%), Endesa (30%) and the Canary Islands Technology Institute (10%).

The system consists of two reservoirs: a lower one with a capacity of 225,000 cubic metres, and a higher one that takes advantage of the terrain, i.e. the natural volcanic crater, with a capacity of 500,000 cubic metres. The wind farm used to pump the water will have a capacity of 10 MW. Any excess energy remaining after pumping will be evacuated to the grid. The hydroelectric plant will also have a capacity of 10 MW, with a net head of 682 metres. Furthermore, the system is supported by an existing diesel engine plant, which would be used in emergencies if there is not water or wind to meet demand.

“The system was designed considering an electricity demand, based on the Canary Islands Energy Plan (Pecan 2006), of 48 gigawatt hours/year in 2015, while expected demand in 2030 has been taken into account when sizing the water pipes and reservoirs, as they are not scalable,” explains the Institute for Energy Diversification and Saving (IDAE), which has contributed to the project.

The hydrowind system “manages to turn an intermittent source of energy into a controlled and constant supply of electricity, thereby maximising the use of wind energy,” IDAE adds. Most of the energy fed into the distribution grid on the island will come from the hydropower plant, while most of the wind power will be used to drive the pumping system, allowing it be stored as potential energy in the upper reservoir and thereby guaranteeing distribution grid stability. Surplus wind power will be evacuated to the grid to provide power to El Hierro’s two water desalination plants.

The project will prevent the annual consumption of 6,000 tonnes of diesel, according to estimates by the developers. This represents a savings of more than 1.8 million per year in fossil-fuel imports. It will also prevent the emission into the atmosphere per annum of 18,700 tonnes of CO2, the main contributor to the greenhouse effect. This is equivalent to the CO2 that could be fixed by a 10,000 to 12,000 hectare forest – an area equivalent to 20,000 football fields. It will also prevent the emission into the atmosphere of 100 tonnes of sulphur dioxide and 400 tons of nitrous oxides, equivalent to the emissions of a coach covering 600 million kilometres.

For additional information:
www.goronadelviento.es
www.idae.es
www.iter.es