Research into cheap solar cells in California's Silicon Valley, United States, is helping to make solar energy more cost-effective.
Nanosolar in Palo Alto can make solar cells 200 times thinner than conventional cells. Their thin film cells are durable and turn about 15 per cent of solar radiation into electricity. But they are not cheap yet.
The company is investigating how to mix nano-sized metal particles into a sort of ink. They can then be printed onto a roll of metal foil that becomes a continuous semiconductor.
Another method under investigation by Konark, a firm based in Massachusetts, uses dyes that produce solar power in flexible plastics.
But making the cells is only half the cost. Solar energy will only be cost effective when mounting, tuning and installing them becomes cheaper, or they become more efficient.
To get around these costs, some companies are looking into how to integrate the cells straight into building materials.
After a decade of buoyant growth, the solar energy market needs to accelerate beyond its current 25 per cent annual growth if it is to provide more than one per cent of the world's energy over the next 15 years.