Finding energy in the sea currently relies on wind, with China making a big splash in producing electricity from offshore wind farms, but waves, tides and currents are possible future sources.
Currently, China and Europe concentrate most of the investments in wind energy offshore, which worldwide has multiplied by 10 in less than a decade. According to the 2021 report of the World Forum Offshore organization, which brings together companies in the sector, the installed power in offshore it was at 4.8 gigawatts but grew to 48.2 gigawatts.
China was responsible for an increase in installed power of 12.7 gigawatts in 2021 alone, with 43 new installations, with 40% of the world totalover 19 gigawattsand with the construction of more facilities, in a total of seven more gigawatts.
Of the 215 offshore wind installations registered last year, 110 were operational in Europe, 103 in Asia and two in the United States, although the US administration expects to have 30 gigawatts of wind production offshore until the end of the decade.
The United States auctioned in February six Atlantic parcels off New York of almost two thousand square kilometres, one of which was acquired by a consortium in which EDP participates.
At the end of the previous legislature, the Portuguese Government announced that will launch wind farm auctions offshore in the portuguese sea.
In the European space, the United Kingdom leads, with the largest number of installations and the largest wind farm offshore of the world, Hornsea 1, off the east coast of Great Britain and a power of 1.2 gigawatts.
In the The European energy objective is the production of 35% of the electrical energy of sources offshore until 2050.
The expansion of the sector has been accompanied by a decline in production prices: in 2021, a report by the US Department of Energy estimated the average cost of energy produced in fixed offshore wind farms to be less than 91 euros per megawatt/hour for projects started in 2020, with a price reduction between 28% and 51% between 2014 and 2020.
The US government provided in that document that by 2030 the average price will be 53 euros per megawatt/hour.
The first Portuguese offshore wind farm has been operating since 2020 in an area with a depth of 100 meters, about 18 kilometers from Viana do Castelo. spawns 25 megawatts of energy, brought to land through submarine cables, and places Portugal in 14th place in the world in taking advantage of the wind in the fields offshore.
At this depth it is not possible to have fixed towers, so the towers of the ‘Windfloat’ park are located on floating platforms anchored to the seabed. On the other hand, the farther away from land, the more constant wind and more ability to generation.
Off Scotland, Kincardine, the world’s largest floating wind farm, is now operational, capable of generating 50 megawatts of power.
Still in the pilot project phase, wave energy is another way of converting the ocean into energy for human consumption, using floating platforms that rise and fall with the movement of the waves and use this movement to activate turbines that produce electricity in its interior.
Portugal had an experience off Póvoa de Varzim in 2008, in what was called a “wave park”, but the project ended up lasting only a few months. A Swedish company is currently carrying out a new test project to convert wave energy into electricity.
In an even more experimental phase are projects to obtain energy from the movement of the tides, using the dam-type mechanism. The water rises during high tide and, as it descends, it passes through turbines whose movement generates energy.
France has the first tidal power plant in the world in the Rance estuary in Brittany and until 2011 the largest, when it was supplanted by another built in South Korea.
The other constant force in the oceans is currents, which in theory could drive underwater turbines similar to what the wind does in wind turbines.
Another experimental form of energy production uses the temperature difference between deep and surface water to create steam and drive a power generator, a process that can also be used to desalinate seawater.
Source: Observadora
