GlobalData’s latest report, Offshore vessels and cables market – market size, competitive landscape and key country analysis to 2020, forecasts annual global offshore wind power capacity to rise rapidly from 1.78 gigawatts this year to about 7.85GW by 2020.

GlobalData senior analyst for power Prasad Tanikella says offshore wind projects are more expensive than their onshore counterparts because the structures are larger, the logistics surrounding tower installation are more complex and costs associated with foundations, construction, installation and grid connection are higher.

However, despite the higher project costs, offshore winds were more powerful and consistent, producing higher energy yields, she said.

“Moreover, high offshore wind power potential and the unavailability of onshore wind power sites are forcing some countries to explore offshore options,” Tanikella said.

Europe is by far the biggest market for offshore wind power, estimated to account for over 90% of global turbine installation vessel revenue in 2013 and GlobalData expects this market to grow substantially into the future.

Despite the many projects currently planned or under construction in Europe, a limited number of offshore wind-specific installation vessels are operating at present, although this number is expected to increase from just two in 2005 to more than 40 by the end of 2014. New vessels are also making installations more efficient.

“Future vessels will allow developers to shorten installation times with increased vessel crane capacity and additional deck space, enabling them to carry more turbines and reduce the number of trips from the onshore port to the offshore site,” Tanikella said.

“The new-build vessels are also expected to reduce weather downtime, as their design will allow them to operate in harsher conditions.”