It’ll be a nice problem to have when the time comes – what to do with the world’s thousands of obsolete oil tankers? Once the transition to clean public transport and electric vehicles is complete, there will be a lot of them going spare. They could be melted down of course, but a recent BBC Future article features a series of alternative uses. Here are three:
Renewable energy – one area of active research is to use tankers as movable power stations by catching wave power. This could be done by creating large ‘moon pool’ chambers in the bottom. As the water washes in and out it creates changes in air pressure, which can be tapped by a turbine at the top. A large tanker could potentially create as much as 30MW of renewable energy that way, according to researchers at Cranfield University and the company ShipEco Marine.
Buildings – an architect in the Netherlands has imagined what it might look like if you took a beached tanker and turned it into a huge public building. Their building includes performance, gallery and retail spaces in a huge steel shell that reminds me of the turbine hall at the Tate Modern’s in London. They imagine in it one of the Gulf states, as an iconic reminder of the oil age once it is gone.
Clean water – in the last couple of years a number of cities have experienced chronic water shortages, and climate change makes them more likely in future. Cape Town is the most famous, and narrowly averted ‘day zero’ when the taps run dry. But what if it cities could call in a huge mobile water treatment plant to support the city’s infrastructure in times of crisis? A Norwegian company called Environor has a range of proposals for repurposing tankers for wastewater treatment or for desalination.
Anything else? Well, you could put a water-cooled, wave-powered data server on one, suggest ShipEco Marine. They also wonder if you could turn a tanker into an enormous multi-storey car park, which is quite creative. I reckon you could design a vertical farm in a tanker too.
If all else fails, you can always take it apart and recycle the steel the old fashioned way.
The Earthbound Report 
So you use the renewable power generated by waves in the tanker to power the desalination plant or hydrogen gas generator…
I wonder if the wave power source would be sufficient to propell the tanker?
Interesting question. I presume the energy needed to move a tanker is enormous, and beyond the scope of this system. But if you had a certain amount of battery storage on board, I imagine it could work as a hybrid system.
These are all good ideas, but ask the US Navy about old ships.
The sea is brutal on ships and they need constant maintenance.
If these retro-fits could generate enough profit to put these ships in to dry dock every 10 years or so for hull cleaning and re-finishing, then maybe these are viable ideas.
Pearl Harbor has many ships in “moth ball” storage. Most will never go back into service. They should be scrapped before they are no longer sea worthy enough to be towed to a commercial ship yard.
A sea without oil tankers will be a beautiful sight.