It is the cleanest, most abundant energy source. But solar power faces the challenge of affordability and efficiency, especially if such systems are to be widely installed in the developing world.
Progress is being made. Scores of Chinese companies are touting their latest solar electronic components and products at an international trade fair in Hong Kong.
Most of the products on display here at the Hong Kong Electronics Fair are practically unusable for the 1.6 billion people, a quarter of the world's population, living without electricity.
In sunny Africa and South Asia, which have the lowest electrification rates, cheaper and more efficient solar cells are in demand.
And innovation is occurring, says Zhong Xiao Jun, whose company in Guangzhou, China makes solar panels, chargers and lighting systems.
"To improve competitiveness of our products, we are working on increasing battery performance," he says. "We are using some printed circuit board to cut energy losses. Secondly, we are increasing the electrical conversion efficiency of solar panels. This is possible because we are utilizing special new materials and techniques for our panel production line."
One of the challenges of solar power, of course, is what do you do when the sun is not shining?
There are innovative solutions, such as this one: a hybrid system that relies not only on solar, but also wind power, for street lamps. It is already operational in Shenzhen, China and Germany.
In North America and Europe, more expensive crystalline silicon technology is preferred for high power, limited space installations.
In the developing world, Topray Solar's Frank Lin says cheaper thin film technology is favored.
"That means they can pay for the same power with less money. Of course, the disadvantage will be a bigger size. But bigger size is not an issue for the African, for the developing countries because they have that kind of space. And usually what they use are smaller applications," says Lin.
More affordable products for daily use in places off the grid are coming to market. Solar flashlights on display here are being sold on a wholesale basis for as little as 35 cents each.
A detachable LED shines up to 20 hours when fully charged and retails for under $100.
Solar power, globally, is reaching new heights every year. Industry officials say installations reached a record high of more than 18 gigawatts last year.
But the top market remains Europe. It is estimated only one percent of the world's solar panels are in the developing world.
