With 276 km² and more than 10000 inhabitants, El Hierro is the
smallest island of the Canary archipelago ( Spain ). The island has its own electricity grid; it is totally isolated as the significant sea depths make any interconnection impossible. Till a little time ago , the electricity demand,
which accounts for about 65% of the internal energy consumption, was
mainly covered by a conventional thermal power station (10MW diesel-fired system). The contribution of renewable energies to the electricity grid was
less than 5% and came from two wind turbines installed close to the main town (100 kW and 180 kW).

The island has a large Renewable Energy potential, mainly wind, and decided to implement a 100% RES project for its energy supply. The latter is a key issue of the “Sustainable Development Plan” defined in 1997 by the Island Government of El Hierro and has became even more relevant since El Hierro was declared a “World Wide Reserve of Biosphere” by UNESCO in January 2000.

> Objectives

The bet on a strategy aiming at the attainment of a 100% RES island already appears within the Sustainable Development Plan of the island, supported
by UNESCO, which defends an advanced concept of Biosphere Reserve as an insular development model and laboratory. The Reserve is characterised by
a high degree of participation of the local population in the strategic decisions affecting development, where energy options are linked to the productive model, to the integral exploitation of endogenous resources, and to population's quality of life.

In the continuity of this approach for sustainable development, the main objective of the El Hierro project is to meet the energy demand of the island using a 100% RES strategy.

Other objectives were also identified and consist of:

- Demonstrating that RES integration is a way of providing 100%
of the energy supply on isolated islands

- Demonstrating that the synergies between different RES can contribute greatly to increasing RE penetration into weak grids in isolated areas

- Demonstrating that the storage of energy in water form is the most
economic way to store energy

- Optimising the available potential of RES by using them together in integrated systems for local power supply

- Demonstrating and widely disseminating the benefits of innovative and integrated renewable energy solutions for islands