Solar Energy : Living Solution to Energy Crisis

Despite the energy crisis and soaring Oil prices, a considearable attention is not going to be diverted to the utiliztion of easy to use Solar energy. Lets have a look to the basic concepts in this regard and after that discuss some possible technologies to utilize this enegry.
Solar Energy is the heat and light radiated from the Sun that drives Earth's climate and supports life. Solar technologies make controlled and efficient utilization of this energy resource. Some of the common solar technologies include photovoltaics which converts solar energy into electrical energy, concentrating solar thermal devices or various experimental technologies.
Before going into details of any of the solar technologies, let us have a brief overview of the significance of solar energy and also how vital is it for our common life.
Earth continuously receives 174×1015 Watts of incoming solar radiation at the upper atmosphere. Approximately 30% is reflected back to space while the rest is absorbed by the atmosphere, oceans and land masses. After passing through the atmosphere, the insolation spectrum is mostly split between the visible and infrared ranges with a small part in the ultraviolet. The total solar energy absorbed by Earth's atmosphere, oceans and land masses is approximately 3,850 x 1021 Joules per year. The point to be noted here is the worldwide electricity consumption was approximately 567 x 1017 Joules in 2005.
Solar power technologies convert sunlight into electricity using photo voltaic, concentrating solar thermal devices, or various experimental technologies. PV has mainly been used to generate power for small and medium-sized applications, from the calculator powered by a single solar cell, the solar powered watch to off-grid homes powered by a photovoltaic array. For large-scale generation, multi-megawatt PV plants are becoming more common. Completed in 2007, the 14 MW power station in Clark County, Nevada and the 20 MW site in Beneixama, Spain are characteristic of the trend toward larger photovoltaic power stations in the US and Europe.
A solar cell which is also called photo voltaic (PV) cell is a device that converts light into direct current using the photoelectric effect. The first solar cell was constructed by Charles Fritts in the 1880s. Although the prototype selenium cells converted less than 1% of incident light into electricity, both Ernst Werner von Siemens and James Clerk Maxwell recognized the importance of this discovery. Following the fundamental work of Russell Ohl in the 1940s, researchers Gerald Pearson, Calvin Fuller and Daryl Chapin created the silicon solar cell in 1954. These early solar cells cost 286 USD/watt and reached efficiencies of 4.5-6%.
The high cost of solar cells limited terrestrial uses throughout the 1960s. This changed in the early 1970s when prices reached levels that made PV generation competitive in remote areas without grid access. Early terrestrial uses included powering telecommunication stations, off-shore oil rigs, navigational buoys and railroad crossings. These and other off-grid applications have proven very successful and accounted for over half of worldwide installed capacity until 2004.
Germany has become the leading PV market worldwide since revising its Feed-in tariff system. Installed PV capacity has risen from 100 MW in 2000 to approximately 4,150 MW at the end of 2007. Spain has become the third largest PV market after adopting a similar feed-in tariff structure in 2004, while France, Italy, South Korea and the US have also seen rapid growth recently due to various incentive programs and local market conditions.
Storage is an important issue in the development of solar energy because modern energy systems usually assume continuous availability of energy. Solar energy is not available at night, and the performance of solar power systems is affected by unpredictable weather patterns; therefore, storage media or back-up power systems must be used.