Every day, 10,000 times more energy strikes the earth’s surface from the sun than is used worldwide. It’s not surprising that with the decline of oil reserves and an increase in awareness of global warming, that research in solar energy is intensifying. A sluggish commodity as late as 2002, solar R&D has now reached a fever pitch, and companies that promise higher electrical output at lower cost have no problem finding investors.
Recent solar breakthroughs encompass photoconversion technologies that mimic photosynthesis used by plants to create energy from the sun, as well as the familiar solar panels employing the photovoltaic (PV) effect, first observed in 1876. The history of photovoltaics can be viewed at www.californiasolarcenter.org. A PV cell is typically made from silicon, and treated chemically to produce a positive electric charge layer on one side and a negative charge layer on the other. These electric charges help to channel electrons that are dislodged by the impact of photons from sunlight on the semiconductor material. Wires attached to the matrix gather the electrons into a useable current flow. Thermal effects and the potential backflow of current must be carefully controlled to achieve maximum efficiency, normally in the range of 14% to 18%.
Photovoltaics have diversified at this point in time, with three basic technologies at the forefront. Some companies use an optical concentrator to focus sunlight energy on wafer arrays: www.energy.gov, while others attempt to drive down the cost of production by using vapor deposition techniques similar to the manufacturing of integrated circuits. More recently alternatives to silicon have been successfully used, such as a polymer-based PV film that can be made into rolls or roofing material, or the plastic spray-on PV material reported on technology portal softpedia.com. Toronto scientists reveal that this breakthrough discovery will gather energy even on cloudy days by absorbing infrared light. At www.greencarcongress.com, a new semiconductor material with a three-band spectral response has been created with a theoretical efficiency of 56%, and promises to deliver up to 73% with a quad-band configuration.
As you read this, astounding progress is being made around the world on metallic forms of solar panels, such as CIS, a thin-film Copper-Indium-Selenium deposition on glass: www.renewableenergyaccess.com, and a related technology known as CIGS, for Copper-Indium-Gallium-Selenium: www.b100.co.za.
A fascinating development is the advent of photoconversion, a versatile technology capable of creating electric power and various fuels from naturally occurring substances such as carbon dioxide, water, and nitrogen. Read the PDF at www.climatetechnology.gov.
The holy grail of solar energy may be the titanium dioxide cell that imitates photosynthesis within the leaves of plants. The Dyesol company has perfected a process that uses a photosensitive dye that will capture significant energy even under low-light conditions: www.treehugger.com.
Even the Bush Administration has stepped up to the plate with the Solar Energy Initiative, proposing to expend $148 million toward the development of solar technologies: www1.eere.energy.gov.
We’re on the brink of making solar energy a practical substitute for fossil fuel, and none too soon.

This entry was posted on Tuesday, February 6th, 2007 at 9:19 pm and is filed under Energy Future, General. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.