The main Energy sources

Geothermal Energy

Geothermal energy is the process of using the heat from the Earth to produce steam and generate electricity in the process. Geothermal resources range from shallow ground to hot water and rock several miles below the Earth's surface, and even further down to the extremely hot molten rock called magma. Wells over a mile deep can be drilled into underground reservoirs to tap steam and very hot water that can be brought to the surface for use in a variety of applications.

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At present, geothermal energy is only used in areas where it is easy to have access to the steam such as in volcanic active places. As of 2008, geothermal power supplies less than 1% of the world's energy
However, new developments in drilling technologies will soon enable drilling deeper into the ground and access to such resources in almost any places around the world. Geothermal has the potential to provide unlimited clean energy for generations to come

Solar Energy: Photovoltaic

There are two ways in which solar energy (radiation from the sun) can be utilized as Energy sources:
Photovoltaic Energy: which is the process of converting solar radiation into electricity through solar panels. Photovoltaic production has been doubling every two years, increasing by an average of 48 % each year since 2002, making it the world’s fastest-growing energy technology. World solar photovoltaic (PV) market installations reached a record high of 2.8 gigawatts peak (GWp) in 2007.
Although the selling price of modules is still too high to compete with grid electricity in most places, the rapid production growth is expected to substantially cut down the price, which will make photovoltaic energy competitive within a few years.

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Currently average Sun power's cells have a conversion ratio of 23.4 %. However, advances past this efficiency mark are being innovated and efficiencies of 42% have been achieved. New technologies of photovoltaic cells are expected to hit the market soon: Fine layer cells and dye cells which will make solar cells much easier to integrate into buildings. New research are under way to capture solar energy directly from space and to transfer it down to earth via micro waves. Concentrating solar energy into new generation high temperature resistant solar cells is also under way and already experimented in Australia. Such technology has great potential. Solar photovoltaic energy is one of the most promising renewable energy sources which may well end up powering cities of the future

Solar Energy: Thermal

Solar thermal energy (STE) is a technology for harnessing solar energy for thermal energy (heat).
Low temperature collectors are flat plates generally used to heat swimming pools. Medium-temperature collectors are also usually flat plates but are used for heating water for residential and commercial use.
High temperature collectors concentrate sunlight using mirrors or lenses and are generally used for electric power production. This is different from solar photovoltaic s, which convert solar energy directly into electricity. Exposure)

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The principal behind high temperature collectors is to concentrate the heat in order to produce, which powers turbines and generates electricity. This process is quite efficient in countries which have large surface areas and appropriate weather conditions (sun exposure)

Wind Energy

Wind power is the conversion of wind energy into electricity, using wind turbines. At the end of 2007, the worldwide capacity of wind-powered generators was 94.1 gigawatts. Although wind produces only about 1% of world-wide electricity use, it is growing rapidly, increasing more than five-fold globally between 2000 and 2007. Large scale wind farms are typically connected to the local electric power transmission network, with smaller turbines being used to provide electricity to isolated locations. Smaller turbines can be used to provide electricity to isolated locations.

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Wind energy as a power source is a viable alternative to fossil fuels, as it is plentiful, renewable, widely distributed, clean, and produces lower greenhouse gas emissions. New research is underway to capture altitude wind which is more constant and would provide a continuous unlimited supply of clean energy.

Hydroelectric Energy

Hydroelectricity is electricity generated by hydro power, the production of power through use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy
Once a hydroelectric complex is constructed, the project produces no direct waste, and has a considerably different output level of the greenhouse gas carbon dioxide (CO2) than fossil fuel powered energy plants (significant amounts of GHG are release during the construction when forests are flooded and gas such as methane emitted during the decay of organic matter).

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Worldwide, hydroelectricity supplied an estimated 715,000 MW in 2005. This was approximately 19% of the world's electricity (up from 16% in 2003), and accounted for over 63% of electricity from renewable sources. Hydroelectric plants however have significant impacts on biodiversity and are therefore considered my many environmentalists not to be Eco-friendly.

Nuclear Fusion

Nuclear fusion is the process by which multiple like-charged atomic nuclei join together to form a heavier nucleus. It is accompanied by the release or absorption of energy. Nuclear fusion occurs naturally in stars. Artificial fusion in human enterprises has also been achieved, although not yet completely controlled. Fusion, the reaction that produces the sun's energy, is thought to have enormous potential for future power generation because fusion plant operation produces no emissions, fuel sources are potentially abundant, and it produces relatively little (and short-lived) radioactive waste (as opposed to nuclear fission which is the nuclear power currently harnessed).
High-power reactors such as the ITER (International Thermonuclear Experimental Reactor) are now under construction in France and other countries. Physicists estimate that exploitable fusion reactors might be operational within 50 years. The main issue remaining to be resolved concerns the storage and movement of the very hot plasma within the reactor and to make the reaction durable (for now the reaction can only be kept running for about 30 seconds due to the extreme heat generated).

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Nuclear fusion is a very promising, clean and sustainable technology which has the potential to power the entire planet by the end of the century. However, for now this technology is not operational. Until it is, other sustainable alternatives must be considered until it is improved.

Coal

This technology involves the removal of a significant part of the CO2 from the coal through chemical and physical means before it is combusted. By doing so, there is much less carbon dioxide released into the atmosphere (up to 80% reduction in emissions). The CO2 removed is stored and then injected back into the Earth’s crust. This technology is debatable as it relies on one of the most polluting fossil fuel energy sources.



 

The idea behind such technology is to try to clean as much as possible the coal burning process which is used by hundreds of thousands of power plants worldwide, while more sustainable alternatives are put into place. This technology should only be used as a temporary solution, as continuing to rely on fossil fuels is a step in the wrong direction. In order to fight climate change, we must completely cease our reliance on fossil fuels and start relying heavily on sustainable energies instead.

Oceans Thermal Energy

If this extraction could be made cost effective on a large scale, it could provide a source of renewable energy needed to deal with energy shortages, and other energy problems. The total energy available is one or two orders of magnitude higher than other ocean energy options such as wave power, but the small magnitude of the temperature difference makes energy extraction comparatively difficult and expensive, due to low thermal efficiency. Earlier OTEC systems had an overall efficiency of only 1 to 3% (the theoretical maximum efficiency lies between 6 and 7%). Current designs under review will operate closer to the theoretical maximum efficiency. There is a lot of potential in the utilization of thermal energy from the oceans. There is an important temperature difference between the bottom of the deep sea and surface temperatures. The Earth's oceans are continually heated by the sun, and cover nearly 70% of the Earth’s surface. This temperature difference contains a vast amount of solar energy which can potentially be harnessed for human use. Ocean thermal energy conversion (OTEC) is a method of generating electricity which uses the temperature difference that exists between deep and shallow waters to run a heat engine. As with any heat engine, the greatest efficiency and power is produced with the largest temperature difference. This temperature difference generally increases with decreasing latitude, i.e. near the equator.