On the edge of the Nevada desert, Tesla, the electric carmaker, is building the world’s largest battery plant. The mile-long, so-called Gigafactory is expected to boost demand for lithium, the raw material used in the batteries that power most electric cars. But the company has yet to announce any lithium supply deals with big producers, leaving it unclear where it will source the lightweight natural material it will need to start producing batteries by 2017 with Panasonic, its partner. The Gigafactory is set to supply batteries for the 500,000 cars Tesla hopes to produce by the end of the decade, as well as to power homes. The company hopes that by supplying its own batteries it can cut its costs per kilowatt-hour by more than 30 per cent, crucial for the mass-market uptake of electric vehicles. But that will require secure, long-term supplies of lithium, more than 70 per cent of which is found in Chile, Argentina and Bolivia. Due to growth in demand for electric batteries, the global lithium market is approaching a shortage, with no new supply coming on stream next year, say analysts. At the same time, battery factories being built in China are set to increase demand for lithium.