> For grid scale storage, which would be needed to get to really high penetration levels of renewable electricity, energy density is even less important. A palt

> For grid scale storage, which would be needed to get to really high penetration levels of renewable electricity, energy density is even less important. A paltry 50 watt-hours/kg would be perfectly fine if the battery also offers low capacity fade per deep discharge cycle and low costs. For grid scale storage there's also options like pumped hydro storage. Cost / kwh can be much lower than batteries, depending on site and scale. Might need to start with a budget of $50m-500m though.