By Martin Patience
BBC News website, Rehovot
Sitting in his book-lined office, Professor Jacob Karni likes to quote the French novelist Jules Verne.
"Yes, my friends," says Prof Karni, director of the Centre for Energy Research at the Weizmann Institute of Science, quoting from Verne's 1874 novel The Mysterious Island.
"I foresee that in the future, water will be used as fuel... water will be the coal of the future."
The professor enthuses about the French author's vision 130 years ago that the world's reliance on fossil fuels is unsustainable.
But he disagrees with Verne, famous for 20,000 Leagues Under the Sea, in one fundamental respect.
Whereas the French writer saw water as the fuel for the future, the Israeli scientist says the future lies with solar energy.
"Even if we were to dam every river in the world and put wind turbines where ever there is wind," says Prof Karni, "it wouldn't be enough to provide for our energy needs. But with solar energy we could meet the world's energy demands."
For the last 16 years, he has worked with colleagues at the Weizmann Institute, situated in a leafy campus in the Israeli city of Rehovot, to make renewable energy a viable alternative.
The professor, who regularly works a 12-hour day, researches how to harness solar energy in a cost effective way and then transport the energy to the user.
The institute has been researching solar panels that produce a greater yield of energy.
"One of the big problems with solar energy is that the energy is very diluted," says Prof Karni. "It can give you a suntan but not much else."
But one of Prof Karni's projects has been to use solar energy to produce a non-polluting synthetic fuel that could be used, for example, to power cars.
Last summer, the Weizmann Institute published research that was "a step towards the solution", he says.
Solar power is finding various other uses worldwide
Using solar power energy, zinc oxide was heated to 1,200C. The temperature splits the ore, releasing oxygen and creating gaseous zinc, which is then condensed into powder.
When the zinc powder reacts with water, it produces hydrogen that could power a car.
The chemical reaction produces no greenhouse gases and the zinc oxide can be recycled into zinc and the process starts all over again.
Prof Karni says that the research demonstrated that the process is achievable, but problems remain.
For every kilogram of hydrogen gas produced, you would need 60 kg of zinc, which is not feasible on a large scale, he insists.
New Manhattan Project?
But with a map of China hanging in his office, Prof Karni insists we have to think big.
"We could put solar panels here," he says, pointing at west China, "and this could provide the energy for the east of China where most people live. We just need to devise an effective way to transport the energy."
The massive consumption in global energy coupled with rising pollution has made finding a renewable energy alternative more important, he declares.
Over 3.5 billion people live in countries where the consumption of energy more than doubled from 1990 to 2003, according to the Energy Information Administration.
If countries were to form a "Manhattan project" for solar energy, employing the best minds and ploughing enormous resources into research, renewable energy could be challenging fossil fuels in five years, the professor believes.
But that moment of reckoning has yet to arrive.
"We will only find the solution when it's really urgent," he says.