One man’s dream of clean energy from mirrors in the desert comes close to reality
Billy Adams – SCMP – Updated on Jul 06, 2008
Given that he has developed a way to effectively save the world, it is probably best not to imagine the years of frustration David Mills experienced trying to enlist support. The respected scientist viewed a small contraption he built in a suburban Sydney car park as a first but important step towards solving the planet’s energy and climate crisis.
As investors baulked at the dollars required to get the technology up and running, only donations from relatives kept his company afloat.
The Australian government soon pitched in A$3 million (HK$22.4 million) but it was merely a stay of execution and as the funds drained, more than a decade of hard toil looked certain to go unrewarded.
At about the same time in 2006, Californian entrepreneur John O’Donnell was flicking through an obscure journal and stumbled on an article by Dr Mills.
It described how landscapes covered in mirrors could soak up the sun’s rays and provide vast amounts of energy. Enough – in theory – to satisfy most of the world’s power and transport demands, eliminating the need for coal, gas, oil and nuclear energy.
If that sounds like the stuff of fantasy, Mr O’Donnell was hooked and flew to Australia. His timing was perfect.
“We had spent most of the government money and we were highly concerned,” recalls Dr Mills. “It was getting close.”
The turnaround in his fortunes has been dramatic and swift. Within a few months of meeting Mr O’Donnell, the University of Sydney boffin and his Australian business partner Peter Le Lievre upped sticks and moved to Silicon Valley.
They were persuaded by US$43 million in funding from venture capitalists Ray Lane and Vinod Khosla, businessmen with formidable track records. Mr Lane is part of a company that invested early in Amazon and Google, while Mr Khosla co-founded Sun Microsystems.
“In Silicon Valley they think on a global basis,” said Dr Mills. It’s a place where the belief that “solar thermal” has the potential to change the world no longer appears to be a pipe dream.
The principle is simple enough. Unlike household solar panels, which have semiconductors to convert rays directly into electricity, sunlight is deflected off an array of large mirrors to heat tubes filled with water. That generates steam to drive a conventional turbine.
While the technology is proven and has operated for some time on a small scale, Dr Mills’ backers believe he has overcome the biggest hurdles preventing thermal’s entry into the mainstream energy mix.
Only working when the sun shines has been solar’s perennial Achilles’ heel, but Dr Mills has come up with a way of storing heat for up to 20 hours – ensuring, he says, reliable power day and night.
Within a few years, he believes, prices for thermal-powered electricity could rival today’s discount provider and major polluter – coal. Racing to drastically cut carbon emissions in the face of global warming, Dr Mills is at the forefront of the many operators seeking solutions through variations on the same solar theme.
Earlier this year the American business magazine Fast Company ranked his firm Ausra as the 20th most innovative in the world.
Dr Mills says these are “exciting times”. He compares today’s renewable energy landscape to the battle a century ago between electricity, gas and the combustion engine to propel the newly invented car.
“We are seeing an explosion in interest throughout the world,” he says from his office in Palo Alto. Governments from Chile to Africa have been on the phone wanting to know more.
“Solar companies are being set up every few weeks, especially in our field. It has turned around completely, to the point where some parts of the industry might consider it a bubble.”
For true believers the potential rewards are mind-boggling.
Dr Mills looks to a future in which massive solar parks filled with flat 16-metre mirrors as far as the eye can see will power vast tracts of our energy-thirsty world.
The Sun – the daddy of all nuclear reactors but without the waste – emits 6,000 times the energy needed by humans at any given moment. And the best places to collect all that natural light are hot, dry areas where few people live.
Ausra estimates mirrors laid out on an area just under 22,000 sq km – or about 10 per cent of the land mass of Nevada – could power the whole of the US. Europe’s needs would be met by linking to similar set-ups in the Sahara Desert.
“In China there is the northwest desert,” Dr Mills said. “In India, the Rajasthan Desert. We see that most areas, most big economies in the world, do have access to a desert or arid area where they can use this technology. The resource is there.”
A small pilot plant linked to a power station in New South Wales began life before Dr Mills left Australia.
Earlier this year utility Pacific Gas & Electric signed a deal to buy power from Ausra’s first US plant, which will be built in California. When it comes online in 2010, enough electricity will be generated for 120,000 homes.
Dr Mills hopes small first steps can inspire industry confidence to raise the billions required for expansion.
The question is not so much whether it will work, but how much it will cost.
Although significantly cheaper than other solar solutions, his thermal technology is almost twice as expensive as a new coal plant. But costs come down as more plants are built. Emissions-trading schemes and carbon taxes will also level the playing field.
For almost three decades Dr Mills has been a leading light in the solar industry.
Along with Qichu Zhang, a Chinese colleague at University of Sydney’s school of physics, he invented advanced heat-absorbing surfaces now used in the majority of solar hot-water heaters.
Most are made in China, which is keen to embrace solar power as a mainstream energy of the future.
Australia should also be on that list, and in the 1970s and early `80s the reputation of the “sunburned country” for encouraging research in renewable energies was second to none.
Dr Mills, a Canadian by birth, was one of a host of international scientists who had headed to Australia to work on scientific breakthroughs.
But the arrival of John Howard’s conservative government in 1996 signalled a downturn in support for alternative energy sources.
Emphasis shifted towards Australia’s biggest export and attempts to create “clean coal”, where carbon dioxide is extracted and pumped underground. The result was a brain drain as renewable firms went out of business or overseas.
Just over a year ago, Dr Mills avoided the former by reluctantly opting for the latter. Two weeks ago, he was visited by a group of Australian politicians who had paid precious little attention to his work when he was there.
“I have spent quite a long time in Australia, and battering my head against a wall for quite some time,” Dr Mills said, adding: “I think there is now real interest. And that is very, very gratifying indeed.”