Here comes the sun
Anthony Doman - Popular
Mechanics
Tue, 25 Oct 2005
Despite a soaring oil price and a panic-stricken
planet scrambling to counteract its profligate use
of energy resources, there is a glimmer of sunshine.
And sunshine is all it takes, says an enterprising
South African academic who is sitting on potentially
one of the biggest solar energy breakthroughs to date.
Against a background of dwindling, non-renewable
fossil fuels and growing concerns about environmental
impact, it’s not just the Greens who are seeking
energy alternatives. Even the oil companies are feverishly
joining the hunt for sources of renewable energy.
Options range from exploiting biomass to harnessing
the power of the oceans, wind, and sunlight.
But they all usually come up against one serious
drawback: cost.
It’s taken 12 grinding years to come up with
a workable solution. And now there is worldwide interest
and support for the technology.
Just one-quarter the cost and significantly more
efficient than conventional solar panels, the thin
film technology is jointly owned by the University
of Johannesburg and the head of its physics department,
professor Vivian Alberts.
Professor Alberts has spent most of his academic
career focusing on silicon, the material that forms
the rock — excuse the pun — on which the
microelectronic industry has been built. The past
decade of that career has been dedicated almost exclusively
to finding a more efficient substitute that could
be used in solar panels.
Glaze lightly, bake well
Solar cell technology has remained essentially unchanged
since the phenomenon was first noted in the 1800s.
The standard for today’s devices is still the
silicon-based panels that have been steadily refined
over the past half-century. Present conversion efficiencies
are between 10 and 15 percent. In direct sunshine
you can bank on between 100 and 150 watts per square
metre of panel.
How to improve on that? Consider this telling comparison:
a typical conventional panel uses silicon slabs over
350 microns thick because of the material’s
poor absorption properties; the Alberts method produces
a five-micron film. That’s a quarter of the
thickness of a human hair.
So it’s thinner. That doesn’t necessarily
make it better. But it is. “Let me put it this
way,” says Alberts. “From the solar energy
point of view, what we have developed is the best-absorbing
material known to us.” Not only that, but it’s
cheaper to produce.
He is talking about a patented semiconductor material,
copper indium gallium selenium sulphide or Cu(In,Ga)(Se,S)2
for short. Five elements that, taken separately, are
pretty pointless as collectors of sunlight. But then
they’re subjected to a bit of high-tech alchemy…
or should that be domestic science?
“You know, it’s a recipe… the whole
thing is much like baking bread,” he says. “You
start off with ingredients that have certain characteristics,
and after mixing, preparing and baking you have a
product whose characteristics are completely different
to what you started with.”
Professor Alberts says the thin film technology he
and his team developed can generate up to 150 watts
of electrical power at a cost below R10 per watt peak.
He adds that it has demonstrated not only high efficiency,
but also long-term performance stability. “The
pilot plant demonstrated that these thin film solar
modules could be produced by highly scalable and proven
industrial technologies such as physical vapour phase
deposition and diffusion processes.” Commercial-scale
thin film modules are being produced with output powers
between 10 and 40W in direct sunlight.
Quoted costs of R10/Wp look highly favourable against
the cost of “traditional” electricity.
And better still against the R35 per watt production
cost of conventional modules. The import price locally
of a silicon-based 50W solar panel is about R2000
(R40/Wp).
[GENI editor's note: see universal currency
converter here]
[As of 2006-04-17, that works out to about $6.58 for
a 50W module, or $0.13USD/watt production cost.]
Small beginnings
Because development didn’t start in the research
labs of a huge multinational, but in the often cash-strapped
confines of a university, the early stages looked
a bit Heath Robinson-ish. “In our labs, nothing
is standard,” Professor Alberts says. “The
thing is, we have a need for equipment that exists,
but is being used for another purpose altogether.
You cannot simply go to a company and say, 'Build
me a diffusion furnace'.
“So everything is more or less custom built.”
In the early days, custom built meant scavenging,
begging, and occasionally getting very, very lucky:
“When the CSIR closed down certain strategic
facilities in the early 1990s we were lucky enough
to get some redundant equipment. Of course, it was
not designed for our purposes, but we were able to
remodel it to create something very useful.”
Eventually, the Department of Science and Technology’s
Innovation Trust Fund granted them R13,5-million to
put together a pilot plant that would demonstrate
the technology’s potential for scalability.
The Minister of Science and Technology officially
opened the plant on the old RAU campus in November
2004.
The early fittings are a far cry from the comparatively
massive modern equipment in the current pilot production
plant. Gleaming stainless steel, comprehensive computer
control and forced ventilation are signatures of the
new pilot plant — sterile is the word.
The metals are deposited on a glass substrate by
sputtering, a standard industrial process. (Sputtering
is used commercially for reflective coatings, for
instance.) The coated glass is then reacted in a diffusion
furnace with specialised gases that transform the
metallic layers into high-quality semiconductor films.
Although Professor Alberts spearheaded the process,
he wasn’t entirely alone. “Naturally,
I worked with a lot of students during the past 12
years. And there is one critical person, Erick Scholtz,
who has been supporting me since 1993. He is my technical
guy. He’s the one who keeps all the equipment
functioning smoothly.”
Into production
The University of Johannesburg and Professor Alberts
recently established a company, PTIP Proprietary Limited,
that houses all the intellectual properties related
to the photovoltaic technology. PTIP recently signed
a licence and technology transfer agreement with a
prominent German company, IFE Thin Film Technology.
The German company has been involved in renewable
energy for more than 25 years and is ranked as the
biggest silicon-based module manufacturer in Europe.
The licence agreement grants IFE a non-transferable,
non-exclusive, right to construct and operate a manufacturing
plant producing 25 MW of solar panels per annum —
half a million 50 watt modules with a typical size
of 120 x 50 cm.
Investment for the first 25 MW phase is €25
to 30-million. Production is scheduled to start in
the fourth quarter of 2007, and the intention is to
increase capacity rapidly once the initial phase achieves
certain performance levels.
At the time of writing, discussions were being held
with a second German company, which is ranked among
the top three producers of silicon-based cell in the
world.
“So in a way those perceived to be our biggest
international competitors became our strategic partners!”
says Professor Alberts.
International licences will hold for five years from
now, during which period a South African consortium
will also put together a local manufacturing facility.
The intention is that, during the initial five-year
period, technology transfer will take place between
Germany and South Africa to enable the setting up
of a South African production facility.
“It wouldn’t be practical to set up here
in South Africa right now for several reasons. We
do have the raw materials and will also have to import
all the critical production equipment from Europe,
which poses considerable technical risks at this stage.
We also don’t have access to world markets to
the same extent as the companies we have become involved
with. Once the technology is established and distribution
networks have been established, it’s a different
story, of course.”
Future possibilities
The government has committed itself to finding clean
alternative sources of energy, having targeted four
percent of total energy production from renewable
sources by 2012. Solar energy has a significant role
to play here, and even for those millions of South
Africans with no access to the national electricity
grid. The prospect of cheaper solar technology will
touch their lives, too.
Long-term, there are possibilities of a grid connection
arrangement, typified by the German market. There,
people are compensated for connecting their solar
systems to the power grid and feeding in clean power,
say Alberts. “It is possible to buy a solar
farm. The owners make more money from harvesting solar
energy than from using the land for traditional farming.”
Although currently the technology is being developed
on glass, other possibilities beckon. “The Central
Energy Fund is keen to develop this for use on rollable
stainless steel, for instance. And we have already
deposited the thin film semiconductor materials on
polymer, which can take on any shape. When it comes
to the substrate, it is really all just about adhesion.”
The product’s flexibility offers the potential
for many niche applications. It’s hardly surprising
that the arms industry has taken a keen interest.
“In concept, the external surfaces of the soldier’s
battledress can become an energy system. You can see
the implications for mobility — no need to carry
batteries.”
Professor Alberts is acutely aware that, although
he has developed a product with tremendous commercial
potential, there is stiff competition out there. “The
likes of Sharp, Shell Solar Industries and BP are
already active role players in the market and will
certainly invest billions of dollars into the technology
in the near future. ”
But for the moment the sun is certainly shining brightly
for Photovoltaic Technology Intellectual Property
(Pty) Limited. And, understandably, they’re
making hay.
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