'Energy Island'

The vast ocean contains endless energy in the form of wind, waves and sunshine. All three can be gathered on the so-called Energy Island - a floating drilling rig 'drill for' renewable energy instead of oil and gas at sea.

Energy Island is the initiative of French inventor Dominic Michaelis. He was frustrated by ocean thermal energy conversion (OTEC), which he said was nothing new. Energy Island, designed by Michaelis and his son, has an OTEC factory and spreads over a 600 square meter area that allows installation of wind turbines and solar receivers.

And yet, ocean wave energy converters and turbines will draw energy from water around the island. According to Michaelis, a hexagonal energy island can generate 250 megawatts of electricity, enough for a small city. The power supply could be much more if the islands were combined into small islands, where greenhouses could be established, clean ports for anchoring boats and hotels for tourists.

The main reason for establishing Energy Island is to exploit OTEC. OTEC is the process of converting the energy generated by the temperature difference between warm water on the surface of the sea and the deep, cold ocean water into heat or other useful forms of energy. OTEC outperforms other marine energy technologies in that it generates electricity all year round. That's because the operation of OTEC is not dependent on the sun, wind or waves but is based on the temperature difference between the warm water on the sunlit sea surface and cold water in the dark deep sea. This difference is most noticeable in tropical waters, where water on the surface measures about 25 ⁰ C. This warm water will be pumped to the Energy Island and used to evaporate liquid, possibly seawater or ammonia gas. The collected steam will be used to run the generator turbine.

The first OTEC factory was built on the Cuban coast in 1930 and generated 22 kilowatts of electricity. Since then, the number of OTEC (both floating and land-based) plants has only been counted on the fingertips, of which the largest factory with a capacity of 250 kilowatt is located in Hawaii (USA). Currently, there are no factories still active.

The main drawback of OTEC is that the efficiency of converting heat into electricity is too low. Some previous OTEC factories use more energy than can be produced. An OTEC plant needs a lot of energy to circulate huge amounts of seawater. Energy Island, for example, estimates it will need more than 400 cubic meters of cold water to be pumped up every second. Because of this limitation, Michaelis has integrated other marine energy technologies to compensate for his OTEC system.

Clean power generated by Energy Island can be led to shore by undersea cable system. Or it could be used to produce hydrogen from water, and this hydrogen fuel is then brought to shore to produce electricity in fuel cells. According to calculations by Michaelis, an energy island will cost about $ 600 million (10.1 trillion). However, electricity is not the only thing obtained from artificial islands. If seawater is used as fuel for OTEC, it will be desalinated through evaporation and condensation. Every time a megawatt of electricity is generated, an OTEC plant can supply 1.1 million liters of fresh water, Michaelis said. Moreover, the source of cold water taken from the seabed is filled with nutrients that can be used in aquaculture.