Man has been using a small percentage of the Earth’s water power for a number of years as many large hydroelectric dams have been constructed. But, this renewable energy resource is only a small fraction of the water power this planet has to offer.
More recently, researchers have been exploring tidal energy, ocean waves and running streams as sources of renewable energy. The Rance estuary in northern France holds the world’s largest tidal power station that generates electricity at regular intervals when the tide comes in or out.
Offshore underwater turbines are also being developed that capitalize on extracting electrical energy from the ocean’s currents. These devices may be setup where the underwater currents are the strongest and generate electricity, which may be stored in batteries or electrolyzed into hydrogen for storage (and run through a fuel cell later) or piped directly onshore, depending upon the distance from the turbines to land.
Companies like Marine Turbines, Swanturbines and Verdant Power are developing these devices. These devices may also be used in large rivers, bays (such as San Francisco Bay) and lakes (such as the Great Lakes).
There is another kind of ocean power device that is also making waves based upon buoys that bob up and down in the ocean and are tethered to underwater generators below. The generators then transmit electricity ashore through a power cable. The PowerBuoy wave generation system from Ocean Power Technologies is one example of this type of renewable energy delivery method.
There is another type of water power in development that harnesses the energy in small streams and rivers to generate electricity. Many large and small developing nations around the world are already using Micro Hydro to create electricity for homes and communities. Pakistan’s Sarfraz Ahmad Khan has come up with a novel approach for hydro electric power generation.
Of course, there is always geothermal energy, which combines heat and water (steam) to create renewable energy. Just north of San Francisco, near Santa Rosa is the Geysers, which is the largest geothermal field in the nation.
No matter what flavor you choose, water power is here to stay. In fact, many believe that water power offers at least as much hope if not more for a renewable energy future than both solar and wind energy.