South Australia, a state of 1.7 million people, is on a renewable energy kick and has encountered price and reliability issues. South Australia first invested in wind power and found wind's reliability to be a problem when it shuttered its last coal plant that backed up the wind power and exposed its ratepayers to outrageous prices and massive black-outs. It then hired Tesla to install the largest storage battery in the world last November--a 100-megawatt lithium-ion battery--to provide back-up for wind's intermittency, at a price of $50 million. Now, it will experiment with solar rooftop panels and Tesla Powerwall 2 batteries to form the world's largest virtual power plant, costing $800 million. The project will cover 50,000 houses to be fitted with 5 kilowatt rooftop solar systems and 13.5 kilowatt hour Tesla batteries that together could provide up to 250 megawatts of solar power and 650 megawatt hours of storage.