Could it soon power the world? The sun is shining on solar power, which is cheaper and more popular than ever. But some countries are resistant to its charms.
Future looks bright for solar energy
Solar gains: Solar panel manufacturers and scientists are hard at work trying to unlock even more efficiency gains from solar panel technology. Glossary
Renewables - Energy sources that do not use up non-renewable fossil fuels, such as wind and solar power.
Plywood - A strong thin construction board consisting of two or more layers of wood glued and pressed together.
Fossil Fuels - Non-renewable fuels such as coal or gas, formed in the geological past from the remains of living organisms.