The world’s first offshore wind project was decommissioned last year, after producing 243 GWh of electricity over 25 years. Commissioned in 1991 in Denmark, the Vindeby installation consisted of 11 x 450 kW wind turbine generators manufactured by Bonus Energy, now Siemens. Sceptics thought it was a crazy idea and only two other offshore wind projects were installed in the 1990s: Tunø Knob in Denmark and Bockstigen in Sweden.
From these humble beginnings, the offshore wind sector has now started to spin. According to WindEurope, in 2017 Europe alone had more than 4,000 wind turbine generators representing almost 16 GW of capacity. The technology has three key benefits over onshore wind: reduced permitting challenges, the ability to deploy at scale, and higher and more consistent wind.
Large wind projects often suffer permitting challenges due to their visual impact, whereas large offshore wind projects may even be invisible from the shore. Moreover, the low-friction surface of the sea increases wind speeds, leading to enhanced generation. These advantages make offshore wind interesting to governments looking to make carbon reductions while avoiding controversy. The largest project currently under construction is Hornsea Project One, in the North Sea off the east coast of Britain. The 1.2 GW development will be equivalent to a large thermal power station, with the ability to generate electricity for more than a million homes.
Until 2015-16, offshore wind costs were typically around €/£140 for each MWh of energy produced. That’s more than three times the cost of thermal power in the UK. Costs have now fallen dramatically, with some projects even proposing to deliver energy without needing subsidies. Technological advances have helped to reduce costs, for example turbine rotor diameters have increased from 100–120 m to 150–160 m, and generator capacities have more than doubled in recent years. Supply chain pressure and reduced financing costs have also helped. Of course, nothing is certain – most low-cost projects have yet to be built. However, given the benefits of offshore wind, lower costs could lead to a dramatic expansion in the sector.
Offshore wind has traditionally been a European business, but new markets have emerged in recent years. The USA finished construction of its first offshore wind project, Block Island Wind Farm off the coast of Rhode Island, in 2016. Growing offshore wind markets in Asia include Japan, Taiwan and India.
Realising the potential benefits of offshore wind generation requires smart solutions that consider a project’s entire lifecycle and are based on multidisciplinary expertise. RINA experts have worked on major offshore wind projects across Europe, providing geotechnical and electrical design work, inspections, technical advisory services, due diligence, energy yield and marine warranty surveyor work.