Water as an Energy Source
Water Energy
Water as an Energy Source
Water energy resources include hydroelectric power from lakes and rivers, ocean energy in its various forms, and energy technologies that take advantage of saline water.
Water energy
If you've ever stood in a fast–moving stream, under a waterfall, or on the ocean shore as waves come crashing in, then you've felt the power of the water. The energy from moving water can be used to create electricity in several different ways. For example:
- a hydroelectric dam
- wave power
- tidal power
A hydroelectric dam
A hydroelectric dam captures energy from the movement of a river. Dam operators control the flow of water and the amount of electricity produced. Dams create reservoirs (large bodies of calm water) behind them, which can be used for recreation, wildlife sanctuaries, and sources of drinking water.
- Flowing water turns a water wheel or turbine.
- A generator attached to the turbine produces electricity.
Wave power
Wave power captures energy from waves on the surface of the ocean using a special buoy or other floating device.
Tidal power
Tidal power, also called tidal energy, is a form of hydropower that converts the energy of tides into useful forms of power, mainly electricity.
Types of water energy
Hydroelectric power
Hydropower makes use of the kinetic energy water gains when it drops in elevation. Typically, water dammed in a lake or reservoir is released through turbines and generators to produce electricity, Hydropower has been a staple of electricity since the beginnings of the electric age. However, very little of this potential is currently slated for development. Significant legal and regulatory impediments, such as land acquisition and environmental protection, will be a part of any major hydro project. Additionally, reservoirs are typically built and managed as municipal water supply and flood control systems and secondarily for power production. This fact lowers the potential impact of hydro development on the energy picture.
Ocean Energy
Three distinct types of ocean resource are commonly mentioned as possible energy sources: tides, waves, and ocean temperature differentials (ocean thermal energy conversion, or OTEC). For example, tidal energy schemes capture water at high tide and release it at low tide. Wave energy generation devices fall into two general classifications, fixed and floating. In both cases, the oscillating motion of an incoming and outgoing wave is used to drive turbines that generate electricuty. Tide energy systems traps high tides in a reservoir. When the tide drops, the water behind the reservoir flows through a power turbine, generating electricity. Ocean thermal energy conversion uses the difference in temperature between warm surface water and cold deep ocean water to make electricity.
Saline Water
Saline and brackish water is common - normally it poses a problem for fresh water supplies. Several technologies, however, can take advantage of saline water for energy production. These include solar ponds and algae production. Solar ponds use the salt water in such a manner that heat from sunlight is effectively locked in the pool and can be used for a number of process heat applications or electricity production. The ability of the pond to store solar thermal energy is unique and overcomes the resource variability that is a drawback of traditional solar development. Salt water algaes grow prolifically under cultivated conditions and can be pressed to extract biodiesel feedstocks or dried and burned for power production. Although neither technology has been demonstrated beyond pilot levels, Texas is fortunate in that regions with saline water resources also tend to be very sunny. If coupled with ongoing fresh water chloride control efforts, exploitation of the saline water resource for energy production may be possible for modest additional investment.
Interesting facts
A natural wonder!
Did you know that one of the world's great natural wonders has been generating electricity for more than 100 years? Today, Niagara Falls is the biggest electricity producer in New York State, generating enough electricity to light 24 million 100–watt bulbs at once!
Leading the way
Hydropower is the leading renewable energy source used to generate electricity in the United States.
Wave of the future
The first commercial U.S. power station using ocean waves to generate electricity is in the works in Oregon. When finished, 10 “powerbuoys” in the ocean will generate enough electricity to power 1,000 homes.
Let’s Protect our Environment!
Hydropower is an environmental friendly and renewable energy source. 99% of all power production in Norway comes from hydropower. On a global basis 1/6 of the power produced comes from hydropower.