The price of silicon has soared by 50 per cent over the past year, curbing the growth of the solar industry and driving up costs. Silicon, made from sand, is a raw material used in semi-conductor devices such as computer chips and the cells that generate electricity in solar panels. Production of silicon has not kept pace with demand from the solar-energy industry, which has soared in the past four years because of the growth in the market for solar panels.

It takes several years to build new silicon manufacturing facilities. But by the end of the decade, annual production capacity is expected to more than double to just under 85,000 tons, which should drive down prices.