Elon Musk’s brave bet to fix Australia’s energy crisis — or hand the money back — landed the tech entrepreneur an hour-long phone call with Prime Minister Malcolm Turnbull and quickly threw him into a debate over whether battery technology is the solution for a nation still wedded to coal for much of its power. Sunday’s call followed a Twitter conversation last week between Musk and Australian tech billionaire Mike Cannon-Brookes in which Musk promised to install and get working a Tesla Inc. battery storage system designed to prevent blackouts in South Australia, the Australian mainland state most reliant on renewable energy.