Use of ocean currents to generate electricity is technically the best new form of power generation. Unlike wind and solar power, ocean currents can produce power 24 hours a day 365 days a year. There is also a tremendous ocean current capacity available. The Gulf Stream off the coast of Florida could produce 400,000 megawatts of power if fully utilized. This is 10 times the power currently being generated in the entire state of Florida.
Ocean current power is also the most environmentally friendly of all existing power generating methods. Like dams and wind power, there are no pollutants or heat generated. However ocean power has the additional advantage of not requiring large tracts of land like dams and wind farms. There also would be no wild life disturbed as dams and windmills have in the past. The ocean turbines are guarded so marine life can not be harmed by the rotating blades.
With all these advantages, why hasn't this source of power been tapped in the past? Cost! There are several companies world wide working on harnessing ocean currents to produce electricity. Some have even built working prototypes. The reason that tidal power has not been exploited more is due to the high capital costs, high maintenance costs and low up time of the existing designs. The existing designs have an electrical generator attached to a turbine rotor submerged in 100 feet of water. This design requires the generator to be enclosed in an air tight capsule. There must be complicated systems to keep the capsule from flooding. Corrosion is another major issue.
Potential capacity is another issue with existing projects. All of the existing designs can only produce power in currents less than 200 feet deep. This means the potential capacity of these systems is limited. The Hills system is practical in depth of 2000 feet so the more plentiful deep ocean currents can be used.
The Hills' water turbine (figure 1) is cost completive with fossil fuels because it uses a maintenance free, totally water proof submersible component that can be operated at depth of up to 2000'. The turbine drives a high pressure water pump instead of an electrical generator. The submerged sea water pump is a simple multiple rubber bellows type piston design that requires almost no maintenance. It is expected that the units can operate for 10 years before requiring any servicing, and then only for barnacle removal and check valve replacement. This key feature allows the unit to be completely waterproof, maintenance free and have a high depth limit. The high pressure water drives a hydraulic motor/ generator unit on shore.