ScienceThe rise of renewable energy has exposed a new problem: energy storage. Late last year, renewables developer North Harbour Clean Energy announced plans to build what would be Australia's largest VRFB — with 4 megawatts of power (the amount of energy that can flow in and out of the battery in any given instant) and 16 megawatt-hours of capacity. VRFB has the potential to store energy at a scale that would dwarf today's largest lithium-ion batteries, Professor Skyllas-Kazacos said