The average size of offshore wind turbines installed at windfarms across Europe in 2014 was 3.4 MW. Progress in foundation design means that installation can be considered for a range of environments, from traditional hammer piling of monopile turbines into sandy sediments in shallow waters (< 40 metres water depth), concrete gravity bases for harder seabed types and jacket structures for deeper water depths, secured with smaller ‘pin piles’. Recent developments in floating wind use tensioning cables to install turbines in water over 100 metres deep (see Figure 3.1), extending the possibility of wind farm construction to deeper offshore areas.