Water Renewable Energy

Hydropower


Renewable Energy in water can be harnessed and used as water is about 800 times denser than air. Even a slow flowing stream of water, or moderate sea swell, can yield considerable amounts of renewable energy.
There are many forms of water renewable energy:
• Hydroelectric renewable energy is a term usually reserved for large-scale hydroelectric dams. Examples are the Grand Coulee Dam in Washington State and the Akosombo Dam in Ghana.
• Micro hydro renewable energy systems are hydroelectric power installations that typically produce up to 100 kW of power.
• Dam less hydro systems derive kinetic renewable energy from rivers and oceans without using a dam.
• Ocean renewable energy describes all the technologies to harness energy from the ocean and the sea.
o Renewable energy in marine current power, uses the kinetic renewable energy of marine currents.
o Tidal power captures renewable energy from the tides. Two different principles for generating renewable energy from the tides are used at the moment:
Tidal motion in the vertical direction: Tides come in, raise water levels in a basin, and tides roll out. Around low tide, the water in the basin is discharged through a turbine, exploiting the stored potential renewable energy.
Tidal motion in the horizontal direction: Uses tidal stream generators, like wind turbines but then in a tidal stream. Due to the high density of water, about eight-hundred times the density of air, tidal currents can have a lot of kinetic renewable energy.
o Renewable energy in wave power uses the energy in waves. Wave power machines usually take the form of floating or neutrally buoyant structures, which move relative to one another or to a fixed point. Renewable energy wave has now reached commercialization.
• Renewable energy in deep lake water cooling is an interesting phenomenon, although not technically an energy generation method, can save a lot of energy in summer. It uses submerged pipes as a heat sink for climate control systems. Lake-bottom water is a year-round local constant of about 4 °C.
Water has a lot of potential for producing green clean renewable energy, Dams and barrages all over the world are producing huge amount of Electricity and has hardly any carbon emissions.

Wind renewable energy

Wind renewable energy in airflows can be used to run wind turbines. Modern wind energy turbines range from around 600 kW to 5 MW of rated power, although wind turbines with rated output of 1.5–3 MW have become the most common for commercial use. The power output of a wind turbine is a function of the cube of the wind speed, so as wind speed increases, power output of a wind turbine increases dramatically. Wind energy can be used in areas where winds are stronger and more constant, such as offshore and high altitude, are perfect wind energy farms.
Since wind speed is not constant, a wind farm's annual energy production of wind energy farms is never as much as the sum of the generator nameplate ratings multiplied by the total hours in a year. The ratio of actual wind energy farm productivity in a year to this theoretical maximum is called the capacity factor. Typical capacity factors of wind energy farms are 20-40%, with values at the upper end of the range in particularly favourable wind energy sites.
For example, a 1 megawatt wind energy turbine with a capacity factor of 35% will not produce 8,760 megawatt-hours of wind renewable electricity in a year, but only 0.35x24x365 = 3,066 MWh, averaging to 0.35 MW of wind energy.
Globally, the long-term technical potential of wind energy is believed to be five times total current global energy production, or 40 times current electricity demand. This could require large amounts of land for wind energy turbines, particularly in areas of higher wind resources. Offshore resources experience mean wind speeds of ~90% greater than that of land, so offshore resources could contribute substantially more renewable energy. This number could also increase with higher altitude ground-based or airborne wind energy turbines.
Wind energy is renewable and produces no greenhouse gases during operation, such as carbon dioxide and methane.