Where wind provides drinking water
The idea was essentially a simple one, like all good ideas. Greece’s islands might be short on fresh water, but not on wind or sunshine – or seawater, of course. Connecting all those factors, and combining them with knowledge and technology and a little imagination, financial backing and the will to succeed, is the stuff of miracles. All these factors came into play in the creation of the impressive structure now ready for launch at the Lamda Shipyards in Elefsina, south of Athens. It is hard to describe in one word. According to the scientists on the project’s coordinating committee, even the services they approached during the construction phase had difficulty fitting it into a category – was it a craft or a platform – as it was the first structure of its kind, the first floating wind generator in the world that converts seawater into fresh water in an environmentally friendly way. «Our idea was to find a way to use technology to solve the problem of drinking water shortages on the islands using renewable energy sources. We would use the wind, sun and sea to provide dry islands with sufficient, cheap, fresh water,» said electrical engineer Nasos Vatistas, one of the scientists on the design team. «At the same time, we had another challenge: The trend in wind generators shows that their future lies in their use at sea. In northern Europe, marine wind parks are becoming more popular. In Greece, they could play a major role in this area, as there are many islands, deep sea and very strong winds in the Aegean,» he explained. Under a consortium of 10 different groups (University of the Aegean, Renewable Energy Sources Center, Region of the Southern Aegean, Lamda Shipyards, Technava, Algosystems, Reflection, EPISEY, the Greek Shipping Register and I. Koumanis and Associates) and with funds of 2.8 million euros from the Competitiveness Business Program, the idea began to take shape. The design stage took three years, while the construction took just six months – a period that will be much reduced in constructing future units. The finished product can produce drinking water for a settlement of 300 people without resulting in any pollution whatsoever. With a small increase in the production cost, it can produce even more. News of the system has already spread throughout the islands which are all fighting to be the first to benefit. «The structure will be towed to one of the 19 Aegean Islands with the greatest water shortages,» said electrical engineer Christos Syrseloudis of the coordinating committee. «We hope to build more soon to meet all existing needs,» he added. Small miracle The system is innovative from several aspects. It consists of a floating platform especially designed to incorporate a wind generator even when exposed to bad weather. Many ships have desalination units but none of them are powered by energy from renewable sources. Most run on diesel engines, with everything that entails. Apart from the harnessing the wind, the unit collects solar energy via photovoltaic cells and uses the best and most environmentally friendly desalination process of reverse osmosis. This allows for a high standard of desalination without the use of chemicals. «The most important result of our research,» said Artemis Maglara, also an electrical engineer on the coordinating committee, «is the fact that all these can operate on variable power. Since the source of energy is wind alone, the amount of electrical energy produced is variable – not with steady voltage as in the home. The most innovative factor is that the desalination system is effective and dependable when the voltage is variable.» In short, not only does the variability not block the system, but because the wind generator is able to swing around to catch even the slightest breeze, it works according to the voltage it receives. Construction phase The structure is an imposing one, resembling a huge metal spider as tall as an apartment building. It is topped by the 30 KW wind generator. On land, its entire bulk is visible, but half of it will be under the surface of the sea after its launch. The main hull is on three levels, the first comprising the central control unit where computers monitor the process. Also on this level are the batteries for storing surplus energy. Another important characteristic is that the structure has automatic control systems for monitoring and operating it from a distance so it can operate independently and completely automatically. That is, operators do not need to be on board. Scientists can monitor the situation via the Internet and can intervene when necessary. In an emergency, they can be briefed by SMS on their mobile phones when they are away from their terminals. The second level contains the desalination plant and the third consists of the fresh water reservoir. Basically, the unit draws in saltwater, desalinates it and stores it in the 25-ton-capacity reservoir. Water can also be stored in four peripheral cylinders. It is rare for a pilot project to serve as a production unit, according to Theodoris Lilas, another electrical engineer on the team. «Usually it takes years for pilot projects, even successful ones, to pass into the production phase. This one can collect data that are of major experimental importance but also do the job it was designed for,» he added. (1) This article first appeared in the November 12 issue of K, Kathimerini’s color supplement.
