FYI,

"Novel Invention Could Mean Cheaper Source of Energy from Solar
Power"
Science in Africa
http://www.scienceinafrica.co.za/2004/november/energy.htm

: Energy security has become one of the hottest political topics in
: the last few years with the prospects of skyrocketing oil prices
: and shortages. Along with the looming dangers of climate change,
: the urgency of alternatives to CO2 emitting energy sources is
: becoming more obvious by the day. One of the most important
: actions to counter these challenges is the establishment of
: alternative energy sources such as solar energy. Latest research
: by South African scientists have taken us one step further to
: realising these goals.

: Solar power

: Solar power has traditionally been differentiated into solar
: thermal and solar photovoltaic (or PV for short) systems. The
: photo-voltaic effect is a phenomenon that depends on quantum
: physics, and allows specific materials to directly convert solar
: radiation to electricity. The photo-voltaic effect is used in
: solar panels, that have been powering spacecraft for decades and
: have recently been making their presence felt in supplying
: electricity to free-standing locations on earth, like telephone
: towers and pump systems on farms.

: However, the panels available commercially today are almost all
: based on high-purity silicon as the photo-voltaic material, and
: these panels are much more expensive than the equivalent amount of
: coal, petrol or gas.

: The only way to make photovoltaic energy more widely used, is to
: make devices (including solar panels) that are much cheaper than
: the current silicon-based devices. The most promising PV material
: identified to date is Copper-Indium-Gallium-Diselenide (CIGS).

: CIGS is much more efficient than silicon at converting incident
: sunlight into an electric current: Less than one micron of CIGS
: absorbs more than 99% of available incident solar energy, compared
: to 350 microns of silicon to do the same job.

: Despite the excitement around CIGS, significant cost savings
: compared to silicon were not achieved, despite 20 years of
: research. However, a new development has made the picture
: considerably brighter.

: Cost-saving CIGS solar panels

: Prof Vivian Alberts of the Department of Physics at the Rand
: Afrikaans University in South Africa and team have developed and
: patented a novel manufacturing technique that finally makes it
: possible to construct CIGS solar panels at a very low cost. The
: method is easily upscalable to industrial output levels, while
: remaining much cheaper to produce than conventional silicon solar
: panels.

: Work done over the last two years indicates that panels can be
: produced in commercial volumes at a cost of about R 500 for a
: 50 Watt panel. This is much cheaper than existing solar panels
: available on the market. CIGS is a remarkably stable material and
: conversion efficiencies should be sustainable for 15-20 years in
: any given panel.

: RAU physicists are currently collaborating with physicists from
: the University of Port Elizabeth and the University of Pretoria to
: make 20 Watt CIGS panels, thanks to an award by the Innovation
: Fund in the national Department of Science and Technology during
: 2003. The award, in the amount of R 13,2 million, has been used to
: construct a pilot assembly facility on the RAU campus (with more
: than R 2 million of top-up funds added by RAU management).

: The two main components of the facility are a state-of-the-art
: sputtering instrument and a state-of-the-art diffusion oven. The
: former was designed by Leybold Optics of Dresden, Germany, and the
: latter by Wilro Technologies in the Netherlands. Both these
: instruments were designed according to Prof Alberts' unique and
: novel specifications and are, at the moment, the only examples of
: their kind in the world. They also constitute the best combination
: of instruments of this kind in the world at present.

: Benefits

: This patented technology has caused great excitement across a
: broad front of stakeholders, since it promises to bring the
: practical cost of applying solar photovoltaic systems for
: electricity production down to a level comparable to coal-fired or
: nuclear technologies.

: Furthermore, the technology contributes nothing to carbon dioxide
: emissions and consumes only the resources used to manufacture the
: solar panels (the metals copper, indium and gallium and the non-
: metal selenium). These materials could in principle all be
: recycled into new panels at the end of the useful lifetime of a
: panel, since no material whatsoever is consumed. The finite
: lifetime (15-20 years) of a panel is simply due to deterioration
: of the crystal structure over time.

: The energy used to make a panel is recovered within 1-2 years of
: operation, beyond which a further 13-18 years of net energy
: production remain. There is no vulnerability to disruptions in
: fuel supply, since sunlight is the fuel consumed.

: In addition, solar photovoltaic technology can be produced in any
: desired amount, from a few milliwatts to many megawatts, if so
: desired. It is not necessary to erect large power stations to
: serve a community with energy from this technology.

: More information:

: The pilot production facility was officially opened by the South
: African national minister of Science and Technology, Mr Mosibudi
: Mangena, on 9 November 2004.

: Sonia Cronjé: Media Relations, Division of Public Affairs, RAU.
: stc@...

Mark Reiff