Re: owners of PV panels
I don't understand why people would buy Tesla's Home battery pack. The lead in a Lead Acid battery is about 100% recyclable, pretty simply. It's lead, oxygen and sulphuric acid. It doesn't burn, though it CAN explode if the vents are blocked and it's either overcharged or short-circuited, though it's not very spectacular. They are looking at re-usuable battery cases on cars / trucks so that the batteries can be completely recycled.
Vehicle Lead Acid batteries are mostly recycled, unlike rechargables in portable/mobile devices.
There is no weight issue with home PV use, weight is the only reason that Lithium cells are used in cars as actually NiMH can be similar volumetric capacity. only slightly less after several months of use. (They weigh a LOT more). NiMH can last longer than Lithium too.
Actually perhaps Lithium rechargables should ONLY be allowed in portable / mobile applications?
It could be argued that Propane made by synthesis from water, waste carbon and electricity solar or nuclear or hydro / wind / wave is more sensible as a car fuel than Lithium batteries. There is actually much more energy wasted within a country transporting electricity on grid and loss of recharging, compared with the energy needed to transport propane from say Sahara to Glasgow.
I first drove a regular car with regular engine with petrol, retrofitted to propane in 1979. You could use either via dashboard switch. It was regular drilled out of the ground propane, not the new-fangled synthesis. Pure electric cars might be a niche, they would need MASSIVE grid investment even if 1/5th of people used them.. Lithium for home PV panel only makes sense to Lithium battery makers selling Electric cars.