x Abu Dhabi, UAEMonday 24 July 2017

A blueprint for green

Feature Wind and water power is set to make the Atlantic island of El Hierro almost self-sufficient from renewable energy resources.

A power plant fuelled by the wind and generating electricity from water is set to make the Atlantic island of El Hierro almost self-sufficient from renewable energy resources. By Carlos Rubio
A tiny and remote Spanish island in the Atlantic Ocean, El Hierro, could hold the key to a clean energy future for hundreds of islands worldwide. The smallest of the Canary Islands, with an area of 278 square kilometres, half the size of Bahrain's main island, El Hierro was the last mass of land that Christopher Columbus saw before he reached the American continent in 1492. Today, its 10,000 residents are bracing for the construction of a wind-pumped hydro plant that will supply most of the island's energy needs from renewable sources.
After more than 12 years of drafting studies and environmental impact assessments, overcoming European, Spanish, regional and local bureaucratic hurdles, and securing a budget of ?64.5 million (Dh337.5 million), construction of the world's first wind-hydro power station is scheduled to begin next month and be completed by the end of next year or the start of 2011. It is the first time anywhere a wind-hydro station will attempt to provide about 80 per cent of the annual electricity demand of an isolated area (in the summer months of June, July and August it is hoped it will cover 100 per cent of the power demand). The rest of the island's electricity needs will be covered by the existing diesel power station and, in the near future, by a combination of other renewable energy sources.
Al Gore's cable television network, Current TV, refers to the island as "a blueprint for a sustainable future on planet Earth". Other places such as the Maldives or the Egyptian resort of Sharm el- Sheikh, with its "green tourism" initiative, are announcing sustainable development projects using clean energies, but none has gone beyond the planning or contracting stage. Samso Island in Denmark claims to have its full electricity needs supplied by the 11 wind turbines on the island, but given the unreliability of wind energy, the island is still connected to the continental power grid as a back-up system. Technologically, Samso's achievement does not represent a major breakthrough, since the grid provides power when there is not enough wind blowing and receives the excess power generated by the turbines when the wind is strong.
On a much smaller scale (6 sq km), work has begun on Abu Dhabi's Masdar City, the UAE's pioneering attempt to reduce the country's enormous carbon footprint - one of the highest per capita in the world because of our reliance on air conditioning, cars and energy-intensive desalination plants - which, it is hoped, will be a model for other cities in the region. The walled city, boasting narrow streets and pedestrian-friendly shaded walkways, will be the world's first zero-carbon, zero-waste, car-free city. Electricity will be generated by photovoltaic panels and a wind farm, while water will be provided by a solar-powered desalination plant. Crops grown outside the city and the landscaping within will be irrigated with grey (recycled household) water and treated wastewater.
The innovators behind Masdar and those behind the El Hierro project will be watching each other with interest. Gonzalo Piernavieja is the director of the Canary Islands Institute of Technology (ITC), the organisation behind the technical details of the El Hierro project, which is being administered by a government-funded company, Gorona del Viento. Piernavieja, a physics engineer by training, explains that the real technological challenge is to create a system based 100 per cent on renewable energies on an island disconnected from the main power grid. Renewable energy sources, most notably wind power, are intermittent and fluctuating, and as a consequence, need be stored in times of excess.
"When you are thinking about providing full power supply to an entire island," he says, "you have to create a massive energy storage system. Since small islands' power grids are by definition weak, you cannot just inject the excess energy into the grid as that would cause the system to collapse. So you need to modulate the flow of excessive renewable energy into the system by replicating more or less what hydroelectric power plants do, modulating the flow of energy into the system according to demand fluctuation."
Here is where El Hierro's Gorona wind-hydro station comes in. This is an innovative concept that combines two renewable energy sources: wind and hydro power, using water as energy storage. The system overcomes the usual problems of discontinuity and power fluctuations caused by the random character of the wind and, thanks to the potential energy storage (pumped water) and the controllable power output of hydro turbines, can establish a stable grid in terms of frequency and voltage.
Among the main components of the wind-hydro system is a wind farm (10-12 MW) which will supply energy to inject directly into the grid or to pump water from a lower to an upper reservoir. The wind farm will be set up on top of a cliff close to the upper reservoir, a waterproofed volcanic crater, located at nearly 700 metres above sea level, but perched only metres from the shoreline. This reservoir will have a capacity of 500,000 cubic metres of water, while the lower reservoir, located at sea level, next to the future mini-hydropower station, can store 150,000 cubic metres of desalinated water. Both reservoirs will be linked by nearly three kilometres of pipes that will distribute water between the two sites.
When wind is scarce and does not cover the demand, the water from the upper reservoir will be released through turbines to the lower one. If a long period without wind has exhausted the water in the upper reservoir, the system will transfer to the existing diesel power station. The capacity of the upper reservoir, half a million cubic metres, is sufficient to meet the energy demand of the island during five consecutive days without wind. It is rare, though, on this island to go more than two days without adequate winds. The system enables the electricity production to match the electricity demand. This adjustment can be achieved because the wind turbines will be able to operate between 10 and 100 per cent of their rated power (by changing the flow rate) with the same efficiency. The estimated yearly electricity production from the system in its initial stage is 36 GWh, of which 24 will come from the wind farm, and the remainder from the hydro station. At the moment, the island's electricity demand is 45 GWh.
It is difficult to visualise this proposed engineering marvel visiting the site of the plant today, where there's only an old diesel power station. The Gorona site is on the north-east coast, just 10 km from Valverde, El Hierro's capital and a few kilometres from the airport. The landscape is quite dramatic, with volcanic mountain peaks falling straight into the sea more than 1,000 metres below. A combination of constant Atlantic trade winds, infinite seawater and abrupt relief makes El Hierro the perfect testing ground for this innovative system. Since its designation as a Biosphere Reserve in 2000, the island embarked on an overall sustainable development programme that includes the conversion of all the island's transport from fossil fuel-based to renewable energies. This will happen once the island's electricity needs are supplied fully from clean energies, some time in the next decade. For this tiny island, which despite its beauty, remains outside the mass tourism circuit of the Canary Islands, the impact of the wind-hydro plant is potentially enormous. "And it will be a very positive one," says Javier Morales, a local politician and businessman in charge of the island's sustainable development programme. He proudly claims to be the first in his family to have been born and raised on El Hierro (his parents and grandparents were born on the island but emigrated to Cuba and Venezuela). Since the mid-1990s Morales and a few other visionaries have been busy searching for "a great project" to bring development to the island but at the same time maintain and protect its unique culture and environment. He hopes that Gorona will be the beginning of a sustainable economic base, with existing agri-businesses such as fishing, wine-making, cheese-making and pineapple plantations moving into organic production. Most importantly, he hopes that the droughts and famines that caused his family to emigrate will become a thing of the past and that young people will return to the island to contribute to its sustainable development, the new buzzword in this part of the world. "It is perfectly possible to live in harmony with your cultural traditions and physical environment and generate development at the same time," Morales says. Another important benefit of the plant will be to reduce its dependence on oil. At the moment, El Hierro requires 26 oil tankers, each carrying 2,000 tonnes, to meet demand. The new system will reduce that to just six tankers per annum. The station will also help to reduce the amount of CO2 emissions - the main cause of the greenhouse effect - by 25,500 tonnes a year. Further down the line, transport on the island will become "clean", virtually eliminating the need for diesel (the island consumes 6,000 tonnes annually). Through the solar thermal programme, authorities expect most homes will switch to such systems for domestic hot-water production, reducing the total amount of electricity used and helping reduce peaks in demand. Finally, the biomass programme is looking at the potential of the island's forestry residues, estimated at 3,000 tonnes, which would allow for the establishment of a power supply system based on gasification of these residues. It was difficult during my visit to the island to find any voices critical of Gorona. From trade unions to political parties, to shop assistants and pedestrians on Valverde's main avenue, all had good things to say about the initiative. Most don't seem to fully understand what the project is about. Politicians say there have been information campaigns to explain to people the environmental and economic benefits of the wind-hydro plant, but they don't seem to have reached most of the people on the street. A journalist explained that most of the young people leave El Hierro to study on the bigger islands such as Tenerife or Gran Canaria, or even Madrid. As a result the population of the island is on average much older than in the rest of the Canary Islands or Spain. This makes it difficult to successfully execute public information campaigns in subjects such as the environment when, ideally, you need to engage people face to face. The only significant public criticism has come from a local cultural association, Ossinissa. Its declared aim is to protect and enhance the island's cultural heritage and unique environment. The association complains that there has not been enough public consultation, and that several flora and fauna species could be threatened by the construction of the plant and its associated equipment. You do wonder whether the ?64.5 million (Dh340m) price tag of the initiative, slightly bigger than the island's annual budget, could have been used in better ways to reach the same target, that of reducing oil dependence. This argument, though, misses the point of the potential positive impact that this test project could have for many other islands around the world should it succeed. This small-scale attempt at sustainable living could have global repercussions, says Tomás Padrón, the island's president. The system could be perfected here and then exported to other insular regions, he says. Islands can play an important role as pioneers of clean energy. They are a stand-alone energy system. In this sense, El Hierro provides a solution for that. Some 300 European islands that are not grid-connected could benefit from this project. Feasibility studies for similar systems to El Hierro's are under way in Crete and 10 other Greek islands, as well as in Madeira (Portugal). Further afield, Taiwan, Hawaii and the Galapagos have already approached Gorona for information on the project. Worldwide, more than 600 million people live on islands, and they could have El Hierro as a reference for what a green energy future would be like: an alternative to oil and other fossil combustibles, and a potentially better quality of life. El Hierro's innovative clean energy system embraces a simple technology: the one offered by nature itself.