In this video, we investigate the promise of offshore wind and its rapid growth. The largest attraction of offshore wind are high mean wind speeds, as shown in the graph to the right. We see that offshore winds have higher mean wind speeds, more frequent high speeds, and fewer periods of low speed compared to onshore winds with lower mean wind speeds, less frequent high wind speeds, and more frequent periods with low wind speeds. In a previous video, we discussed this list of desirable wind characteristics. When evaluating offshore wind against these characteristics, we find that offshore winds offer high wind speeds. When speed variability is weighted to higher wind speeds rather than periods with little wind, seas have little surface roughness leading to good wind shear characteristics and little turbulence. Wind directions tend to be stable in air density is good since offshore turbines are at sea level by definition. On these measures, offshore wind resources are very attractive. This map shows mean coastal offshore wind speeds around the world. We see that there are excellent wind resources along the coast of Europe, North America, the Northern Pacific coast of Asia, and the Southern shores of Africa, Australia, and South America. We also observed that offshore wind resources are less abundant in tropical latitudes. Another important consideration for offshore wind is the existence or absence of a continental shelf. This illustration shows how continental shelves are shallow water extensions of continental landmasses. Installation of offshore wind is much easier in shallow water than deep water, of course. This next map illustrates the presence of continental shelves around the world, shown in light green. Extensive continental shelving is found along the West Coast of Europe, the Northeast Coast of North America, Southeast Asia, and the southeast coast of South America. This next map shows population densities around the world. The highest densities are in Europe, India, Southeast Asia, Northeast North America, and on the East Coast to South America. Putting all of this information together, it's not surprising that most existing and planned offshore wind projects are in Europe, Northeast North America, and the Northeast Coast of Asia. These regions exhibit good wind resources, extensive continental shelving, and large population densities. Other regions with similar characteristics are shown by the white turbines. An outlier in this analysis is the west coast of Central America, where floating offshore turbines are planned. Offshore wind has many advantages. Offshore winds are excellent resources of energy with high mean wind speeds, and woodwind variability skewed to high wind speeds. Good offshore wind resources are often near major coastal population centers, and so do not require long distance transmission lines. Offshore wind do not interfere with other land uses. Very large wind turbines are feasible due to easy access to offshore wind sites using shapes, and often offshore wind sites can be located far from shore and out of sight. However, offshore wind has disadvantages relative to land based wind. Disadvantages includes construction of offshore facilities is more expensive than onshore due to the need for fixed and floating subsurface structures, and undersea electrical cabling to show is also expensive. Offshore wind turbines operate in a hostile marine environment with salt water and salt spray, which is corrosive to wind turbine structures and equipment. Plus violent storms and hurricanes can cause physical damage to offshore turbines. This hostile work environment makes ongoing operations and maintenance that much more costly than on land. Finally, environmental impacts of offshore wind are not yet well understood, including the impact of offshore wind structures on fisheries and oceans ecosystems. But despite these challenges, the advantages of offshore wind apparently outweigh its disadvantages. As interest in offshore wind energy is growing rapidly. Offshore winds provide abundant and accessible wind energy in resources. With attractive high wind speeds, with variability skewed to high wind speeds and with low turbulence. Offshore wind facilities can be often located near major metropolitan population centers, reducing transmission costs to energy hungry cities. Finally, we should note that offshore wind is in its early stages of development, so we can expect that challenges with implementation will be mitigated and costs will decline rapidly. So in summary, offshore wind is the next frontier of wind energy.
