energy project showing the lower reservoir
and hydroelectric plant near the sea, and the
upper reservoir and wind farm higher up the hillside.
Located about 1500 km off the Spanish coast in the Atlantic ocean, El Hierro is the smallest and most remote of the Canary Islands, an archipelago of sun-drenched Spanish islands and one of Europe’s most popular tourist destinations.
Like many remote islands, El Hierro generates electricity with diesel oil transported from mainland terminals by oil tanker. The carbon impact is significant – in El Hierro’s case it amounts to 18 200 tons of CO2 per year in power generation emissions alone, an impact that the renewable energy project will eliminate.
The project consists of an 11,5 MW wind farm and an 11,3 MW hydroelectric pumped storage plant that will provide the island’s 11 000 inhabitants with 80% of their energy needs. The remaining 20% will be generated by solar thermal collectors and grid-connected photovoltaic systems.
ABB is playing a lead role in the project by providing a power and automation solution that will electrify and control the hydroelectric pumped storage plant, and integrate into the island grid the energy generated by wind and hydropower turbines.
Overview of the El Hierro renewable energy project showing the lower reservoir and hydroelectric plant near the sea, and the upper reservoir and wind farm higher up the hillside. The upper reservoir will have a capacity of 556 000 m3 of water, which can generate enough hydropower to meet the island’s electricity needs for seven days.
The solution 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 REF 670 intelligent protection system.
An important challenge 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.
At the two pumping stations, motors, variable speed drives and dry-type transformers will power the pumps at high levels of reliability and ensure that the entire process is smooth and efficient, consuming minimal levels of energy and reducing equipment wear and tear.
Scheduled for completion in 201l, the project is fast becoming a model for other communities striving to become self-sufficient in renewable energy.
The entire renewable energy project will be controlled by an distributed control system (DCS). Based on ABB’s System 800xA extended automation platform, the solution 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.
By communicating with the wind farm, the 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.
The Greek island of Icaria is already building a hydro-wind project modeled on El Hierro, and the power industry as a whole is following the project closely with an eye to larger scale implementation.
Contact Shivani Chetram, ABB, Tel 010 202-5000, shivani.chetram@za.abb.com
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