The first offshore windfarm in US water was built in 2015:
http://motherboard.vice.com/read/first-us-offshore-wind-farm
Jack-up rigs can be converted for construction of offshore wind power: If they want to stay in business, companies like Seadrill must upgrade their ships to support offshore wind / tidal / solar power installation:
http://newatlas.com/meygen-tidal-energy-scotland/45396/?li_source=LI&li_medium=default-widget
In a long shot, those ships could serve as launch platforms for space exploration because moving platforms closer to the equator reduces the amount of rocket fuel needed to reach orbit.
If used in fuel cells instead of engines or turbines, crude oil, natural gas and methane hydrate will remain viable sources of energy in the the future.
https://worldoceanreview.com/wp-content/downloads/wor3/WOR3_de_Kapitel_1.pdf
https://worldoceanreview.com/wp-content/downloads/wor3/WOR3_de_Kapitel_2.pdf
https://worldoceanreview.com/wp-content/downloads/wor3/WOR3_de_Kapitel_3.pdf
https://worldoceanreview.com/wp-content/downloads/wor3/WOR3_de_Kapitel_4.pdf
With the beginning of the Russian invasion of Ukraine, there has been a scramble among European countries to secure enough new LNG supplies to counteract the dwindling Russian deliveries of natural gas through pipelines such as NordStream 1.
As LNG requires the prior existence of LNG-capable terminals onshore, the lack thereof creates major hurdles when it comes to severing the ties with Russia in the energy domain. Luckily, there are special ships called FSRU (Floating Storage Regasification Unit) which are capable of turning the liquid natural gas back into gaseous form which can then be injected into the existing European pipeline network.
LNG carrier ships should be designed to also allow the transport of ammonia to facilitate a hydrogen economy. Built as FPSO ( Floating Production Storage and Offloading Unit), they could make use of surplus wind energy and produce ammonia. The first of those ships is named P2XFloater.