A Curious Tale About Solar Panels

THE SEPTEMBER 2006 ISSUE OF SCIENTIFIC AMERICAN was dedicated to exploring the future of energy beyond the carbon era.?The editors share a sobering outlook: 'Decades may pass before hydrogen-powered trucks and cars relegate gasoline-and diesel-fueled vehicles to antique auto shows.'?Until that happens, we’ll 'muddle-through' somehow.

But why does it take so long for some energy technologies to get from the lab and industrial applications to the service of consumers? Take solar panels, for example.

A high-street electronics chain in London now sells educational solar-power kits for around the ￡20 mark.?Serious, roof-dwelling solar panels that will power equipment in your home sell in DIY superstores at around ￡2,500. That’s a price-tag for the wealthy or very committed, but at least consumers can push their trolleys past the technology.

SOLAR PANELS HAVE ONLY RECENTLY APPEARED on the shelves of retail outlets, so you'd forgive them for posing as new technology.?But they're not. While England was priming itself for what was to become its most famous World Cup, a contributor to the July 1966 edition of Wireless World faced a copy deadline for the magazine. His name was D. Bollen, and he provided a circuit for a solar-powered battery charger.

As he put it: 'The ability of solar cells to convert sunlight directly into useful electrical energy has been well demonstrated in satellite applications. An advantage of the solar battery is that is allows true, unattended operation in locations remote from a power supply and…promises an outstanding degree of reliability.’

Over four meticulously-illustrated pages, Bollen goes on to provide a blueprint for a circuit that will trickle-charge a battery from a solar cell.?Bollen shows that you can run something that uses one milliamp of current for '2.74 hours' in a 24 hour period. He leaves us guessing what application he had in mind for this tiny current, but the rig could also have powered the bulb of a toy torch for a few seconds a day.

Still, the circuit is there and the date is mid-1966. Don’t be distracted by Bollen’s talk of ‘satellite applications’. His circuit is a million miles from rocket-science – in fact it’s the simplest of the bunch in this edition of a magazine that was pitched at everyone between novice constructor and electronics professional.

Someone with barely any experience could have thrown a demonstration version of this circuit together in fifteen minutes flat. And all the parts were available from specialist suppliers in London and south-east England.

The listed supplier for 'assorted selenium and silicon cells'??is International Rectifier. I contacted the company to find out how much a similar solar-cell cost at the time Bollen wrote his feature.

A single cell measuring about a centimetre by two centimetres cost four dollars, right up to 1966.?In his feature, Bollen describes various combinations between one cell and four, so the most expensive part of his circuit cost between four and 16 dollars, or about $25-100 dollars in today's money.

World's first solar-powered car: 1912

But what came back from International Rectifier (IR) proved far more interesting than price information. It turns out that the company had demonstrated the world's first solar-powered car - a 1912 model of the Baker Electric - as early as 1958. They achieved the stunt by making a high-output solar panel - less than two metres long and just over a metre wide - from a whole bank of little solar cells.?

Commercial, industrial and military customers went on to buy solar panels from International Rectifier.

SO WHY HAS IT TAKEN ALMOST FIFTY YEARS for solar panels to reach our shops??

Southface, a non-profit, sustainable-living organisation based in the USA, point out that solar-cell technology has had been uselessly competing against the relative fall in price that occurred in the fossil-fuel market in the nineties.?

But Southface believe that major orders of consumer solar cell units in countries such as Japan may finally signal the start of an era when solar cell production will benefit from economies of scale.?

I hope so. In the meantime, it's anyone's guess how long will it take for the consumer-led technology revolution to swat our energy problems.

--- ?Alistair Siddons, 2006