Australia has put itself on a realistic path to achieving what climate activists around the world have long dreamed of: running its power grid entirely on renewable energy. The Australian Energy Market Operator oversees the nation’s power markets. Chief among them, the National Electricity Market serves about 90 percent of customers, minus remote areas and the west coast. ​“They’re getting replaced by the least-cost energy, which is renewable energy, backed with storage, connected in with transmission. AEMO has developed a clear sense of what is needed to keep the lights on whenever coal power flickers out, he said.