South Australian Premier Jay Weatherill has brushed aside federal government disinterest in the state's plan to build the world's biggest battery to help stabilise its energy network and bring down electricity prices.

Billionaire entrepreneur Elon Musk’s company Tesla will build the 100 megawatt lithium ion battery within 100 days or deliver it for free. But acting Prime Minister Barnaby Joyce has dismissed the project as a nice idea but too small to make much difference.  “It’s a good idea but the capacity…