I wonder if "stay at home" policies effected older drivers more than younger drivers. Younger drivers are learning to drive at older ages that the used to so may have less experience. Gone are the days of driving being taught in high school.

Wikipedia says "Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing. ... The round-trip energy efficiency of PSH varies between 70%–80%, with some sources claiming up to 87%." The Energy Vault website just says the is has "higher round trip efficiency" than large scale pumped hydro storage". Could they use dead lithium ion batteries as their weights? I've wondered why wind turbines don't have such a system in or on their towers. Having to deal with such strong lateral loads, it seems that they would be over designed for vertical loads. It might even assist in stabilizing the towers.

My Volt has heated seats and steering wheel. Part of a $500 option. The only thing that is cold when I use them during our mild California winters are my feet. I wish they had an infrared led shining on them.

I think this van would be a big hit as a camper. When I camp here in California I see a lot of Mercedes Benz Sprinter vans. There are cheaper vans but I people buy the MB for the status. Throw some solar panels on top so you can camp for a while in remote locations without losing range.

I hope you are right that my Volt battery will last 10 years. My last 2 cars, a 1995 Civic and a 2000 BMW 323, I kept for 20 and 17 tears respectively and both had well over 200k miles. But assuming the 3000 charging cycle life of Lion batteries, the 50 miles of driving electric on the Volt for 300 days a year would indeed last 10 years. But the Model 3 longe range has a range of 322 miles so driving 50 miles 300 days a year would only use 46 cycles of the battery per year so assuming the 3000 charging cycle life of it's batteries it would theoretically take 65 years for the battery to need to be replaced! In reality I think Lion batteries in cars last anywhere from 500 to 2000 charging cycles. And with the 50 miles per day of charging you could keep the Tesla battery well below the maximum and minimum charge allowed by the manufacturers allowing the Tesla battery to get more cycles of life than the Volt.

I have a Chevy Volt with a range extender. I love it! I often use all the 50 miles of battery range on my drives for work. I like to fiddle with the hold button and I've gotten up to 60 miles of battery range and 60 mpg on an 100 mile drive by using only the battery to accelerate (something that Chevy could easily do with software if they put their mind to it). But I know that range extenders are a bit of a gimmick. Because I use the full charge of the battery on my regular 50 mile commutes I will wear the battery down quickly and soon will be driving mostly on gasoline or need to replace the battery. It makes more sense to have the life of the battery last at least the life of the car. The Volt weighs as much as battery powered only equivalent car. Once the Tesla 15 minute fast charge is widely available, the advantage of being able to fill up quickly with gas will vanish.