Offshore winds are stronger and less gusty, thus they allow to produce more wind energy than on land. There are large areas for the construction of power plants available offshore, and the growing shortage of land areas (especially near big cities consuming a lot of electricity) proved that the relocation of wind energy away from land is a very logical step. At the same time, already at a distance of 10-15 km off the shore, an offshore wind farm will not change seascapes.
The operational principle of offshore wind farms does not differ from the land ones. The essential difference lies in the conditions of installation and usage.
Offshore wind energy is considered to be a relatively new technology. Just recently some countries, in their desire to achieve maximum efficiency of wind power, have begun to build offshore wind farms. A pioneer in the sector of offshore wind energy is Denmark. It was there that the world's first offshore wind farm was established in 1991. It was called Vindeby, had the capacity of 5 MW and consisted of 11 wind turbines from Siemens (0.45 MW each).
Denmark today is still among the top three countries in terms of installed capacity of offshore wind farms, second only to the UK and Germany.
According to the Global Wind Energy Council (GWEC), 2015 was the first significant year for offshore wind energy. The added capacity of wind turbines accounted for about 3.4 GW, which led to a total installed offshore wind capacity of over 12 GW.
Based on the results of 2015, Europe has surpassed the mark of 11GW of installed offshore wind capacity. And more than 91% of offshore wind farms all over the world at present are set off the coast of Europe (with more than 60% of them located in the waters of the North Sea). Currently, the average capacity of offshore wind turbines in European waters is 4.2 MW, the average water depth – 27.1 m, the average distance from the shore – 43.3 km.
However, even given its obvious advantages, the development of offshore wind energy was much slower than that of the land one. This delay happened for various reasons, which can be attributed to the difficulty of conducting the work in a marine environment, and the high cost of offshore wind turbines, as well as the cost of connecting to the grid.
The construction of wind farms on water is expensive, and therefore only pays off if a wind farm produces the required amount of energy. Offshore wind energy does not cease to develop, steadily reducing the high capital costs. Today, there are already floating wind turbines that do not require the installation of the foundation.
The European Commission has repeatedly stated that offshore wind energy is recognized as the key technology in stimulating the EU economic systems. At the annual conference and exhibition of the European Wind Energy Association EWEA-2015 (held in Paris in November 2015), the Vice-President of the European Commission for Energy Union Maroš Šefčovič said, “Offshore wind energy, especially taking into account the energy networks of the North Sea, has great potential to spread a new wave of "green" energy.”
Offshore wind energy is an important component of achieving Europe's energy industry restructuring towards the production of energy from renewable sources. In addition, China has set a goal to reach 30 GW of installed capacity on their coast by 2020. And the United States, which has the potential of offshore wind 4 times exceeding the current energy consumption, has already launched the active development stage of offshore projects.
Since most of the world's largest cities are located near the shoreline, large-scale development of the global offshore wind energy seems very promising, which will make it even more efficient and competitive. And in the long term, offshore wind energy will become a truly global industry.