Comment by Animats

The next thing is what's happening in batteries. Solar panels are great, but you need storage to go with them. Battery prices dropped about an order of magnitude over 12 years.[1]

Energy density continues to improve. At some point, one of the half-dozen companies trying to get production cost down for solid-state batteries will probably succeed. That gets about 2x the energy density per unit weight over lithium-ion, plus charging times under 10 minutes. Then fast chargers can replace gas pumps on a one for one basis.

Fixed energy storage doesn't need more density, just lower prices. Lithium iron phosphate batteries are just fine for that. Retail chains with huge flat roofs (Walmart, Target, etc.) are going in heavily for solar and batteries.[2] The power bill for air-conditioning those huge spaces quickly justifies it.

This is now entirely driven by the economics. No more need for subsidies.

[1] https://www.statista.com/chart/23807/lithium-ion-battery-pri...

[2] https://electrek.co/2024/11/19/corporate-america-is-investin...