Energy and marine equipment manufacturer Wärtsilä South Africa on March 31 said the country would need more than 28 GW of flexible assets, including more than 21 GW of energy storage and more than 6.8 GW of flexible gas power capacity, to run on 100% renewable energy at the lowest cost. The capacity needed to balance South Africa’s switch to grids powered by intermittent renewables must come from two key technologies, namely energy storage and flexible gas power capacity, capable of running on future fuels. Future fuels can be produced during periods when renewables produce more electricity than is needed, said Wärtsilä Energy South Africa business development manager Wayne Glossop.