Home | Products | Green Energies | Fossil Fuels | Environment | Downloads | Links | About TFE | Log In |

Solar Energy - The Eternal Nuclear Fusion Reactors in the Sky

The are two different main technology streams that have been developed to trap solar energy. One is called solar themal, which uses reflectors and piped water to collect the heat energy. The other is using materials that show photo-electric properties such as silicon and other semiconductors which absorb solar energy as light and generate electricity. These are called photovoltaic and photo-electrochemical devices.

The technology to harness this energy in a form that can be adapted for the current day requirements will require further development before it becomes cost effective. The current day installations of the solar panels for buildings has an average life time of 25 years. So it can be cost effective in the regions of regular and abundant sunshine to have roof top installation of solar panels. As it stands there are relatively cheap solar panels that can produce electricity for limited and special requirements. It is not uncommon to see the Solar panel decorated homes with part dependence on Solar power for heating and lighting. These energy efficient homes are possible only in the developed countries where sufficient affordability is there for the initial cost of installation. However with greater public awareness and participation this can in fact be made more cost effective. In places of abundant Sunlight even simple traps such as solar light inlets and wind operated ventilators reduce the heating consumption from regular power supplies. These being cost effective, are increasingly used in modern buildings. 

In general the panels convert the light to electricity by a simple mechanism of electron excitation by the absorbed photon. The overall mechanism is as illustrated generation of free conduction electron at p-n junction, i.e. at the junction of p-type and n-type semiconductor. A semiconductor such as Si having a band-gap which corresponds to the available energy level of the visible light spectrum can be used effectively. It would be most efficient to use single crystal Si. However it is more cost effective to use polycrystalline Si which are cheaper to manufacture. At the p-n junction due charge migration i.e., electrons from n migrate to fill the holes on the p side of the junction. Because of this a region of charge depletion is created at the junction. This causes shift in energy levels causing an overall effect called schottky barrier. The shift in the energy of the top of the valence band and the bottom of the conduction band due to p and n type impurities is called the fermi level. This is seen to be approximately at the middle of the bang-gap in the middle of the depletion region. Electron excitation from the fermi level to the conduction band happens at this junction. These electrons result in the observed photovoltaic current.

Although solar powered cars have been regularly showcased, for it to be practicable, the energy efficiency of the panels have to be much more to reduce cost and surface area outlay. The current day reported efficiency of photovoltaic panels does not warrant its use to totally power motor vehicles. However modern day innovators have not lost the enthusiasm to try the panels for not just road travel, but also for air travel. Panels on extended wings of airplane have been showcased for fuel efficiency and improvement in reduction of emissions. The most effective use of solar panels is on artificial satellites for powering sub-orbital flight.

In places where the Sun light is abundant and is available all the year around, a simple trapping of the Solar energy as heat using simple heat transfer technology is used to generate steam which in turn is used to generate electricity by turning steam turbines. For instance, Siemens is providing steam turbines for Nevada Solar One, a solar-thermal plant whose collectors cover an area of one square kilometer. The collectors focus sunlight and reflect the concentrated energy onto steel pipes filled with heat-transfer oil, which is then used to heat water in a heat exchanger. The resulting steam drives a 64-MW Siemens turbine. When it goes on line this summer, the facility will supply about 40,000 households with electricity. 

Another way to trap sunlight is to use it in Photo-electrochemical devices where the sunlight excited Si electrode can effect important chemical reactions such as splitting of water to yield Hydrogen. These are yet to be commercialized in any significant way. Main limitations being low efficiency.

The natural biochemical traps such as chlorophylls have been subject of much research. Algae have been effectively used in the manufacture of many useful products. These are discussed in the Bio-Reactor section.

Of more recent interest are certain synthesized novel materials such as semiconductor polymers which are also effective traps of visible spectrum photons. i.e. they exhibit interesting electrical and chromatic activities upon interaction with the visible light. Composite materials such as polymer-fullerene blends are of great interest in achieving high efficiency low cost solar panels

News

• One of Europe's largest module assembly factories is to be built in Spain by BP
• Largest private solar unveiled in California
• GT Solar increases capacity
• India's largest grid connected solar farm
• Sharp plans massive hike in thin-film cell production
• More Wacker silicon for ersol
• New solar output on Majorca
• Austra to construct solar themal power plants in Las Vegas
• NanoSolar announces new lower-than-coal solar panel
• Experimental installation powers up the house totally on solar energy all the year around 
• D.I.Y. Solar - Hydrogen power
• A better way to put it back into the Grid - A Science Daily report
• Life cycle efficiency of renewable energy 
• Efficiency Boost Makes Solar Cells Cheaper
• Nano flakes may revolutionize solar cells
• Organic Solar Cells: Electricity From A Thin Film
• Thin-layer Solar Cells May Bring Cheaper Green Power
• Efficiently Organic - Researchers Use Pentacene To Develop Next-generation Solar Power
• New World Record Achieved In Solar Cell Technology
• Sandia, Stirling To Build Solar Dish Engine Power Plant
• Researchers Envision Mass-produced Rolls Of Material That Converts Sunlight To Electricity
• Solar Power- New World Record For Solar to grid Conversion Efficiency Set
• Smarter Energy Storage For Solar And Wind Power 
• Low cost concentrators made of balloon reflectors with the advantage to withstand high wind situations 
• Si inlaid optical fiber construction - for special electronic adaptations
• Rainbow solar cells constructed out of different sized quantum dots to absorb over the entire solar spectrum of light
• Cheap new solar cells made much more efficient 
• Japan to build massive solar collector in space by 2030
• Expert forsees 10 more years of R&D to make Solar Energy competitive

'Science without religion is lame; religion without science is blind' - Albert Einstein

"I'd put my money on the Sun and Solar energy. What a source of power! I hope we don't have to wait until oil and coal run out before we tackle that" - Thomas Edison 1847-1931

Home | Products | Green Energies | Fossil Fuels | Environment | Downloads | Links | About TFE | Log In |

Disclaimer

Free Hit Counters

Green energy, Environment friendly energy, renewable energy, alternate energy resources, bio-diesel, fossil fuels, Solar energy, wind energy, water power, hydro energy, hydrogen fuel, crude oil, clean coal, global warming, Geo energy, vacuum energy. Green energy, Environment friendly energy, renewable energy, alternate energy resources, bio-diesel, fossil fuels, Solar energy, wind energy, water power, hydro energy, hydrogen fuel, crude oil, clean coal, global warming. Geo energy, vacuum energy. Green energy, Environment friendly energy, renewable energy, alternate energy resources, bio-diesel, fossil fuels, Solar energy, wind energy, water power, hydro energy, hydrogen fuel, crude oil, clean coal, global warming.