Our supplies of solar, water and wind energy are more than humanity would ever use should we harvest it all. Yet renewables share at least one glaring problem: consistency. Despite the vast flows of sunlight, wind, and water across the Earth, their irregularity (or intermittency) make them difficult to tap as baseload power which utilities must supply around the clock. This has helped keep coal and gas-fired turbines humming as the choice for baseload power, and fueled the argument that renewables will not truly supplant fossil fuels for all our energy needs (although several studies suggest it’s possible by 2050).
One solution has been to combine two complementary renewable energy sources into a single reliable generating unit. Solar and wind are one such duo. These hybrid power generators (along with batteries) are being used for off-grid applications, and cited as candidates to replace conventional energy generation. But a 2010 review in Applied Energy found that while such hybrid generators are feasible, the "design, control, and optimization" (PDF) of the systems pose an expensive challenge.
Now wind and water are getting a turn.
Off the shore of Japan, the oil and gas engineering firm Mitsui Ocean Development & Engineering Company is floating a new type of power plant this fall. Combining turbines for wind and ocean currents, the platform will support vertical wind turbines spinning 154 feet (47 meters) above the sea surface, while a cylindrical turbine 49 feet (15 meters) across turns just below the waves, reports CBS via Japan’s NHK News. The clever omnidirectional turbines—a three-bladed Darrieus turbine for the wind, and bucket scoops of a Savonius current turbine—allows the platform to serve as the hub for both turbines regardless of wind or current direction. If it becomes operational, the prototype should generate enough power for 300 homes.
Turning a prototype into a utility-scale reality, however, can take years and billions of dollars. With $224 billion flowing into renewable energy investments annually, reports Bloomberg, such schemes now have a shot at success.