Alternative sources of energy are also known as renewable energy sources. Alternative energy sources are generated from natural resources like wind, rain, tides, Sunlight, etc which can be naturally replenished.
Some examples of alternative energy sources are:
• Solar power
• Wind power
• Tidal power
• Wave power
• Geothermal, etc
Solar power and solar energy are mostly used synonymous. Generally the term solar power is used to refer to the electricity that is generated from the Sun. Solar energy technologies can be used for day-lighting, hot water, active and passive solar buildings, for cooking, etc It can be used for various needs but mainly solar energy is used for generating electricity.
Approximately 174 petawatts of solar radiation at the upper atmosphere is received by the Earth. And approximately 30% is reflected back to the space. The rest is absorbed by oceans, land masses and clouds. Solar thermal technologies can be used for space heating, water heating, heat generating and space cooling. To heat water solar hot water systems are used. In geographically low latitudes 60-70 % of the domestic hot water can be provided by solar heating systems. The two most common types of solar hot water systems are glazed flat plate collectors and evacuated tube collectors. In the US, heating, ventilation and air conditioning (HVAC) systems totals to 30 % of the energy used in commercial building and 50 % in residential building. For utilizing solar energy, solar chimney is also used which is a passive solar ventilation system comprised of a vertical shaft which is connecting the interior and exterior of a building. Solar energy is also used for making saline or brackish water potable and this is called solar distillation.
Wind energy is synonymously used with wind power. Converting wind energy into some useful form such as electricity is known as Wind Power. Wind produces just 1 % of electricity in the world, this rate is ever increasing. Europe is ahead compared to other continents in development of offshore wind power turbine. Europe has shallow water in North Sea and the Baltic sea due to which wind turbines can be placed there.
There are two types of wind turbines separated by the axis in which they rotate. They are:
- Horizontal-axis wind turbines
- Vertical-axis wind turbines
Since wind speed is not constant, wind farms annual energy production cannot be calculated exactly. We could estimate but it depends on nature. There is also a danger to birds flying around wind turbines. Some advantages of wind power are that it requires no fuel for its operation and has no emission compared to electricity production.
Biomass is also a renewable energy source and it means any living or recently dead biological material which can be used as fuel or also for industrial production. In other words biomass means plant matter grown to generate electricity or produce Biofuel. Biodegradable wastes are also included in biomass. The largest biomass power plant is in North America named New Hope Power Partnership.
Biofuel is obtained from liquid, solid or gaseous fuel got from recently dead biological material. Biofuels are produced from any carbon source. Biofuels are mostly used for heating homes, cooking stoves, etc
Tidal power is also called as tidal energy. Tidal power means the power we get from the energy of tides and then converting it to electricity or something other. Tidal power is not widely used in the world but it can be very useful to us.
Wave power is the power we get from the transport of energy by ocean surface waves and then utilizing this energy for some good work. Wave power and tidal power are two different sources of power.
The energy which is generated from the heat stored in the Earth is called geothermal energy. It also means collection of absorbed heat got from underground. But today also geothermal power supplies are less than 1 % in the World. Geothermal power can be available 24 hours a day. The sources of geothermal are hot water, shallow ground, and even hot molten rock called magma. Deep wells are constructed in underground reservoirs for taping steam and hot water and then they can be used in a variety of applications.