Solar energy belongs to the class of renewable energy technologies.
Solar energy, radiant light and heat from the sun, is harnessed using a range of ever-evolving technologies such as solar heating, solar photovoltaics and solar thermal electricity.
The total solar energy absorbed by Earth’s atmosphere, oceans and land masses is approximately 3,850,000 exajoule per year.This is roughly more energy in one hour than the world uses in one year. Photosynthesis captures approximately 3,000 EJ per year in biomass.The technical potential available from biomass is from 100-300 EJ/year. The amount of solar energy reaching the surface of the planet is so vast that in one year it is about twice as much as will ever be obtained from all of the Earth’s non-renewable resources of coal, oil, natural gas, and mined uranium combined. Solar energy can be harnessed at different levels around the world, mostly depending on distance from the equator.
As can be seen fromthe above statistics Solar Energy has an almost unlimited potential to supply the world with energy.
Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Active solar techniques include the use of photovoltaic panels and solar thermal collectors to harness the energy. Passive solar techniques include orienting a building to the sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air.
In 2011, the IEA said that the development of affordable, inexhaustible and clean solar energy technologies will have huge longer-term benefits. It will increase countries’ energy security through reliance on an indigenous, inexhaustible and mostly import-independent resource, enhance sustainability, reduce pollution, lower the costs of mitigating climate change and keep fossil prices lower than otherwise.These advantages are global. Hence the additional costs of the incentives for early deployment should be considered learning investments; they must be wisely spent and need to be widely shared.
2. Solar Energy Share of Energy Market
The solar energy share of the total world energy market has been growing rapidly over the last ten years, although it still represents a relatively small part of the total world energy market (less than 1%). This is mainly due to the high cost of solar energy and the large government subsidies that are required to make solar energy commercially attractive.This situation has improved since the availablity of cheap solar panels made in China. Also, the techical development of solar energy technology does not stand still.
The diagram below indicates that Solar Energy accounts for about 6.5-7.0 % of the global market of renewable energy.
3. Solar Energy Environmental Impact
Solar panels are made from silicon wafers. To produce silicon that can be applied in the wafers a lot of energy is required. Many studies have been conducted to determine the grey energy of solar panels.The grey energy is the time that it takes a solar panel to produce the energy that it took to produce the Solar panel.
At this moment this grey energy is 2-4 years depending in the applied technology, location where the panel is installed and the type of application (solar heating or solar based electricity production. This is why the CO2 emission associated with the operation of solar panels is relatively high, in the range of 50-70 CO2 equivalents per KW production capacity.
3.Solar Energy Production Economics
As Solar panels are relatively inefficient and are expensive to produce the installed cost per KW is high.The capacity factor for solar panels is between 20 and 25 % depending on the location.
Where the climate is warm and counts many hours, the generation of solar energy is more efficient than in other less favorable locations.
The costs of installed capacity is in the range of 3000-4500 US$/KW.As the capacity factor is about 20-25%, the effective installed cost of solar energy is between 15000-18000 US$/KW.
Therefore Solar Energy is currently the most expensive way of of producing renewable energy. Also the grey energy is very high in comparison to other renewable sources of energy.
4. Solar Energy Summary and Conclusions
Energy produced from solar installations contribute about 1.0 % of the total global energy production.The future growth of solar energy will depend many factors.As the technology develops further it is expected that solar panels will becomoe more efficient, the grey energy will be reduced and the cost will decline.
So far the industry could grow very fast because of many government subsidies. In Germany solar and wind energy have been subsidised to a great extend by paying producers a very high feed-in- tarrif for excess electricity delivered to the electricity grid.
Due to this high feed-in-tarrif the wind and solar energy industries have ﬂorished in Germany over the least decade. It is conservatively estimated that Germany pays a subsidy of about 14 billion Euro per year. This is ubnsustainable in the long run.
The future of solar energy depends to a large extend on new technology development and on the development of other technologies which are currently in the development phase all around the world.