Solar Power: Oliver’s Sun Traps

Barbados' Oliver Headley has dedicated a lifetime to developing viable applications of solar energy

One night in 1957, the calm of a district in Barbados known as Mile And A Quarter was shattered by the launch of a home-made rocket blasting 300 feet into the air. This was no childish prank: it was a young Barbadian scientist saluting his peers — the Russians who had successfully launched Sputnik 1. With the help of his chemistry teacher, Oliver Headley and his classmate Peter Whitehead had designed solid fuel rockets, using potassium chlorate, sugar and sulphur.

Anyone who knew Oliver Headley as a boy could see he would one day make his mark on the scientific world. His mother Daphne, when driven almost to distraction by her son’s burgeoning activities, would confine the inventor and his inventions to a single room in the family house.

The forecasts were correct. The Hon. Oliver Headley, Professor of Chemistry and Director of the Centre for Resource Management and Environmental Studies (CERMES) at The University of the West Indies (UWI), has dedicated a lifetime to developing viable applications of solar energy.

Headley is one of those scientists who have been able to make a real difference to people’s lives. Across the Caribbean, solar water stills are used to produce distilled water; solar crop dryers are used by farmers from Belize to Guyana. If Barbados relies heavily on solar water heaters these days, put it down to Professor Headley’s advocacy. The turning point, he says, came when the then Prime Minister, Tom Adams, discovered that a solar heater could reduce his electricity bill considerably, and proceeded to give citizens tax concessions on water heaters. Today about 40 percent (some 28,000) of the houses in Barbados have solar water heaters, manufactured by three local companies.

During a recent talk in Jamaica, Headley told an amazed audience: “Jamaica receives 77 trillion watt hours per day courtesy of the sun. This is the equivalent of 47.6 million barrels of oil per day, most of which gets radiated back to the sky. The plants use less than one percent of that, so you are throwing away some 46 million barrels of oil a day.”

The sense of urgency that drives Headley’s solar energy research is triggered by two factors — the potential economic benefits, and the threat to the planet if alternatives to fossil fuels are not found. That includes the real possibility that rising sea levels will in time flood half of Barbados and Trinidad, not to mention the coasts of Guyana and Florida.

Headley is a lively speaker, his lectures peppered with historical anecdotes which endear him to the most scientifically challenged.

The greenhouse, he reminds us, was actually invented by the gardener of Emperor Tiberius who found, “quite by accident”, that this was a good way to grow cucumbers in winter. One of the earliest uses of solar energy, he points out, was by the Greeks at the siege of Syracuse in 212 BC, when they reflected sunlight from their shields onto the Roman ships and set them on fire. “That story was assumed to be apocryphal, but the Greek Navy repeated the experiment in 1973, and actually set fire to a rowing boat, so it is perfectly feasible technically.”

Oliver Headley’s solar energy research was sparked off by a friendly discussion. It was 1969, and he was a member of faculty at the UWI campus in St Augustine, Trinidad. He remembers sitting on a sunny patio with fellow scientist Dr Basil Springer, when they were challenged by a colleague from social sciences to “stop dabbling in pure science and use the abundant Caribbean sunshine to create something useful.”

The two men rose to the challenge. The next day, Dr Springer arrived with a roll of aluminum foil, which Headley used to produce a solar still for distilling water. It was the start of 25 fruitful years which brought unexpected benefits both to the campus and to the Caribbean.

Headley and Springer made the St Augustine campus self-sufficient in the production of distilled water, a vital ingredient for laboratory work. Solar stills were designed and produced for schools to use in their science programmes. Solar energy was harnessed for electricity: thanks to Headley’s team, a school in a remote Trinidadian village “acquired photovoltaic windpower and a diesel generator backup, and now has the most reliable electricity supply in Matelot.”

But perhaps Headley and his colleagues are best known around the Caribbean for their work on solar dryers. They have worked extensively with rural farmers, starting out by producing dryers for root crops such as cassava, yam and potatoes, and later for bananas, grasses to be used in handicraft, and timber for furniture making.

The simplest of the dryers is the wire basket dryer, used to dry foodstuff containing a large amount of water and little solid material. Over 200 have been built around the region. “Small farmers love it,” says Headley. “There is nothing to go wrong, and if something does go wrong, it is nothing that cannot be fixed with a hammer and nails.”

Another simple device, the cabinet drier, is built in wood and plastic in its cheaper forms, or more elaborately in metal and glass. A variation of it uses rocks placed in the drying chamber to retain heat so that the dryer stays hot during cloudy periods and after sunset. Timber dryers are more complex and expensive, costing US$15–30,000 — which, according to Headley, is still about a quarter of the price of their electrically-powered, imported counterparts.

Interest in crop-drying is mushrooming around the Caribbean, as entrepreneurs discover that almost anything that grows naturally in the region can be dried and marketed. In Belize, where some 25 percent of the banana crop usually had to be dumped, farmers are now discovering that the rejected fruit can be dried to make a completely new product — banana raisin. In addition to increasing the shelf life of crops and reducing spoilage, crop-drying allows food preservation without the use of additives.

He used to give away the designs,” Head-ley says. “However, the current Vice-Chancellor basically told us: ‘Go out and apply your solar energy skills to make money — hopefully for the University.’”

The solar energy programme, like a number of others at UWI, has been identified as a potential income-generating centre. A company is being formed to market the technology and to develop appropriate technologies to solve specific problems.

Cost is a major obstacle to wider applications of the technology, solar electricity for example. The challenge is to get unit costs down to a level where they are equal to or cheaper than traditional sources of energy. “The photovoltaic cells, for example, are now being sold at US$4.00 per watt. And we have 1,100 watts on a roof. That is US$4,400. If you want to run your whole house on photovoltaic cells then you’re talking about US$12,000 just for the cells.”

This is why Headley and his team have put a hold on such projects as solar-powered air conditioners and refrigerators (the latter has been replaced by a more economical solar ice-maker, a project they hope to complete soon). But you can’t help feeling that the man who launched a rocket from Barbados to greet the Sputnik is going to find a way to make all these things work in a way people can afford.

“Only one percent of science may be useful,” he says, “but that one percent can feed many people.”