That thought occurred to two professors at the University of New South Wales in Sydney, who have been tinkering with artificial photosynthesis for years, and they claimed recently to be on the brink of success. Janusz Nowotny and Chris Sorrell told an international conference in Sydney last month that they expect to be extracting hydrogen from water on a large scale within seven years.
"Based on our research results, we know we are on the right track," Nowotny said in a press release issued prior to the conference.
"We have abundant sunlight, huge reserves of titanium and we're close to the burgeoning energy markets of the Asia-Pacific region," Sorrell added. But, he said, the same technology could be used anywhere.
So, success is at hand, right?
Maybe, but maybe not.
Others have made similar claims, leading to disputes that at times have been vitriolic.
Chemists at Duquesne University in Pittsburgh announced two years ago in a paper published in the journal Science that they had achieved an efficiency of 8.35 percent in the conversion of solar energy to hydrogen extraction. That's considerably higher than most other claims.
But they came under immediate attack, with one critic claiming their "remarkable achievement" was meaningless because they had used electricity, not just solar power, in their experiments. Even the Japanese researchers jumped on them for not citing their earlier work.
All of that reveals the importance of this research. The stakes are enormous, and the rewards could be astronomical, if this idea ever moves from the lab to the factory.
In the meantime, there's that bit about sunflowers.
Valerie Dupont, an energy engineer with the University of Leeds in England, told the national meeting of the American Chemical Society last month that she and her colleagues have developed a "hydrogen generator" that pulls hydrogen out of sunflower oil using only air and water vapor and two catalysts, one nickel-based and the other carbon-based.
Dupont reported that the generator produces hydrogen that is 90 percent pure, which she says is better than most other methods. But it also produced carbon dioxide and methane, two greenhouse gases.
And even if it works perfectly, there's still that old problem of scale. How many sunflowers would have to be sacrificed just to fuel those English cabs zipping around London?
Lee Dye’s column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.