Elon Musk announces Tesla's plan to build world's biggest lithium ion battery in South Australia – video

The billionaire founder of Tesla announces the building of the 129MWh battery to store renewable energy in South Australia, and confirms his pledge to deliver it within 100 days or it will be free. Musk tells reporters the project will not be without technical challenges, given it will be the largest battery installation in the world ‘by a significant margin’