22 April 2021 The electricity industry is making a rapid transition towards 100% renewable energy, but do we know for sure how to keep the grid stable without any old-style, ‘synchronous’ coal generators? Australia’s energy ministers are poised to release a proposal from Energy Security Board for a redesign of the National Electricity Market. This question of ‘security’ will be a key issue. Historically, coal generators have supplied up to four-fifths of Australia’s electricity. Since 2010, 12 coal power stations have retired and there are 18 left in the NEM. In March 2021 EnergyAustralia announced it would close the Yallourn power station in 2028. We need to redesign the system to be secure without coal.