Solar power drives everything on this planet, from ocean currents to the trade winds, all of which could be used to generate electricity for the increasing power demands of human civilization.
Ocean currents can be harvested for their energy, but the equipment to do so has often been expensive and limited in scope. Previous generations of ocean current turbines could only be used in shallow waters because they were practically impossible to retrieve for maintenance. Working at depth is much more difficult than at height, so bringing ocean current generators to the surface is the only easy way to do it.
In order to fix some of these problems, a new prototype has been developed, looking something like a 1950s cartoon rocket ship, with three pontoons and a central fuselage. The pontoons lend stability and make it easy to maneuver into place for power generation. The central fuselage contains the generator and gearing, while the only exposed piece is the turbine itself.
The design was specifically meant for deep water applications, where more ocean currents can be located out of the way of shipping lanes. At the same time, because of its weight and manueverability, the new generator can easily be surfaced. I’m speculating here, but it seems that perhaps the pontoons could be filled with air to facilitate surfacing for maintenance?
The smaller prototype has been fairly successful. Future versions could see larger and more efficient systems. The 1MW prototype is about 1/10th the size of a traditional ocean current turbine, and should be cheap enough that “a medium-sized shipyard” could afford it, according to researchers at Polytechnic University of Madrid.