-- snip --Mr Frydenberg said more than 40 per cent of South Australia's energy supply comes from renewable energy, but emphasised that was not the cause for the blackout. "That does raise questions for the stability of the system — not just for supply, because when the wind is not blowing and the sun is not shining, electricity is not being generated — but also for the stability of the system because of the frequency that is generated as opposed to base-load power which has historically been more coal and more gas," Mr Frydenberg said. "So questions are raised by...