Is $0.03 the purchase price of the energy capacity or the actual energy generation cost? Journalists need to learn how to explain the figures they use. A footnote with the actual equation seems appropriate because if you can't understand the equation used to derive the figure then you really shouldn't be writing or reading the article anyway.
Clean electricity generation paired with the first grid-level sodium battery energy storage system can bring costs down to just $0.028 per kWh. The 10 MWh storage capacity is executed with sodium-ion cells that can be charged in just 12 minutes.