Sunday, February 23, 2014

Solar energy potential, current issues and future role

Solar energy is form of renewable energy that receives the lion share of media coverage. There are several reasons for this with most obvious being that Sun is free and practically unlimited source of energy, for at least next five billion years. Solar technologies are constantly developing and are vastly improving its cost-effectiveness ratio as compared to other energy sources though it also has to be said that solar energy is still some way off from achieving cost parity with traditional sources of energy (fossil fuels). Solar energy technologies are usually divided on active and passive solar energy technologies. Active solar energy technologies include photovoltaics and solar thermal collectors to harness the energy from the Sun while passive solar technologies include methods such as orienting a building towards the Sun or selecting materials with favorable light dispersing properties.

Many energy experts agree that clean solar energy offers our civilization huge long-term benefits. These not only include positive impact on climate change and less pollution but also limitless source of free energy that is the most abundant of all other energy sources on our planet. Fossil fuels, as many of you already know, are finite energy sources, meaning they will eventually become exhausted, and once this starts to make toll world needs to have adequate alternatives ready, so why not give solar energy a change it most definitely deserves?

What exactly is energy from the Sun?

Sun radiates enormous amounts of energy. It has been said that our planet receives 174 petawatts (PW) of incoming solar radiation at the upper atmosphere, with 70% of this gigantic amount being absorbed by clouds, oceans and land masses. It has been estimated that the total solar energy absorbed by Earth's atmosphere, oceans and land masses is approximately 3,850,000 exajoules (EJ) per year. Energy from the Sun is essential for all life on our planet, and our planet is heavily dependent on this energy. Without solar energy there also wouldn't be photosynthesis, a base for the entire food chain on our planet. Harnessing solar energy to power our entire industry and society in general is currently a dream but in years to come this dream could well become a reality, after all this is pretty logical conclusion when you consider the total amount of available solar energy and the miniscule amount of this total number we need to power our world.

Sun radiates enormous amounts of energy.
Solar energy development – The challenges that need to be overcome

Solar energy industry is still fairly young in terms of development, and therefore still lacks the "proven technology" mark that other energy sources, most notable fossil fuels, have. The lack of maturity of solar energy sector means that efficiency is still inadequate and that the total costs are still too high, meaning that solar energy industry still has a mountain to climb in order to become cost-competitive with fossil fuels.

The prices of solar energy technologies are still relatively high but the good news is that they are also constantly declining though still not enough to compete with the costs of fossil fuels without the subsidies. High costs, lack of maturity in development, and the lack of tradition are top reasons why solar energy is still couple of decades away before achieving cost-parity with fossil fuels. Solar energy storage issue is also one of the challenges for young solar energy industry. Sun doesn't shine at night or when it is cloudy or raining so what the industry needs is an adequate solar energy storage technique that would do the job in these situations by providing reliable supply. The scientists from all over the world are currently working on solar energy storage issue and the world still eagerly awaits effective solution to this issue.

What exactly are photovoltaics?

Photovoltaic is term with which we are often bombarded with by solar energy industry. The best way to define photovoltaics would be to say that these are devices that convert sunlight into electricity by using the photoelectric effect. Solar cells are also often referred to as photovoltaic cells, and they aren't exactly the brand new technology as some people think they are. The creation of first photovoltaic cell is more than one century old as the first one was constructed by Charles Fritts in the 1880s. It also has to be said that the first significant application where solar cells showed their potential and worth was as a back-up power source to the Vanguard I satellite in 1958.

Photovoltaic cells are made of semi-conducting materials very similar to those used in computer chips. There are several different types of photovoltaic cells and it is still early to tell which one will win the commerciality race; among those that are currently mostly used are thin film, monocrystalline silicon, polycrystalline silicon, and amorphous cells.

Concentrating photovoltaics is also well known term used by global solar energy industry. Photovoltaic cells that are designed to operate with concentrated sunlight are built into concentrating collectors that use lenses to focus the sunlight onto the cells. It is fair to say that this may not be an ideal solution because the lenses must be pointed at the sun so the efficient use of concentrating collectors is really limited to location with the highest solar insolation values. However, concentrating photovoltaics are advantageous in terms of costs because they use very little expensive semi-conducting materials.

An average photovoltaic cell has an efficiency of 15%, which means that less than one-sixth of the sunlight striking the cell actually generates electricity which means that efficiency levels are in need of massive improvement in order for photovoltaics to rule the global energy market and achieve cost-parity with fossil fuels.

Current usage and conclusion

Solar energy can provide us with over 1000 times more energy than this world currently needs but despite of this enormous potential solar power is yet to reach tiny 0.03% of the world's total energy supply.

There are several answers to the question why the world isn't using more solar energy to satisfy its huge energy demand. As already said above solar energy technologies are still in the very early phase of development, which gives us an answer as to why solar power still fails to achieve efficiency comparable with fossil fuels. An average solar panel has an efficiency of around 15 percent, which means that large amount of solar energy gets wasted, and ends up like a heat instead being turned into some form of useful energy. The intermittency is also one of the burning issues that solar energy sector will have to find the solution for in the form of adequate solar energy storage method. In fact, making solar energy panels lot more effective and far cheaper is what global solar energy industry needs to dominate. The science will have to play its part, and so will the politics because without politics science cannot obtain the necessary funds needed for further research and important new discoveries. Luckily, many of the world countries favor solar energy and the sector has become well subsidized in the recent years which resulted in many favorable policies for future solar energy development in much of the world. It 's no doubt that solar energy industry will continue to develop and further improve, and if all goes according to the plan, in one moment of the time, solar energy will become the dominant form of energy on our planet. It's difficult to predict when exactly will this moment come, but there are very few of those who doubt future leading role on solar energy industry on global energy market.

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