Submarine power plant generates under pressure

You don’t need to travel 6.8 miles down into the Mariana Trench, like James Cameron did, to know that the deeper you dive under water, the more the water pressure increases. Heck, you probably found that out the first time you dove into the deep end of a swimming pool.
Now a group of Norwegian scientists from the SINTEF organization want to put that pressure to good use by building a power plant on the ocean floor. “Imagine opening a hatch in a submarine under water. The water will flow into the submarine with enormous force. It is precisely this energy potential we want to utilize,” Rainer Schramm, inventor and founder of the company Subhydro AS, explained in a press release. Schramm is working in conjunction with SINTEF to bring the concept to reality.
The proposal calls for turbines to be connected to large tanks at a depth of approximately 1,300 to 2,600 feet. When valves on the turbine are opened, water rushes in and turns the turbine. The mechanical energy creates electricity. When the water tanks are full, the turbines are run in reverse and function as a pump, sending the used water back up to the top, a method called pumped storage.
“A pumped storage power plant is a hydroelectric plant which can be ‘charged’ up again by pumping the water back to the upper reservoir once it has passed through a turbine,” Schramm said. “This type of power plant is used as a ‘battery,’ when connected to the power grid.”
Although this process sucks energy from the grid, Schramm says the degree of efficiency is just as high as that of conventional power plants.
“We envisage that this type of storage plant will function well in conjunction with, for example, wind farms,” he added. “At strong wind conditions, excess electricity is sent subsea to pump water out of the storage tanks. In periods with little wind, energy can be obtained from this underwater plant instead. The same applies to solar generation: the pumped storage power station can contribute to constant electricity production at night time when there is no sunshine to run a solar power plant.” A submarine power plant of average size is expected to produce roughly 300 megawatts over a period of seven to eight hours and be enough energy to supply over 200,000 British households with electricity.