Figure 4
![Figure 4](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2F2046-9063-10-8/MediaObjects/12999_2014_Article_60_Fig4_HTML.jpg)
Types of offshore wind turbine foundations (reproduced from ref. 102, source Principle Power). Monopile and tripod/jacket foundations are currently proven technologies. Floating structures have been using three main types of foundations, which are adapted from the oil and gas industry: the Tension Leg Platform (TLP), semi-submersible (Semi-sub), and Spar Buoy (Spar).