January 26, 2020
A quick excursion into the reality of batteries.
One barrel of oil contains about sixteen hundred thirty kilowatt-hours of energy and weighs about three hundred pounds.
A Tesla "Powerwall 2" battery holds about thirteen and a half kilowatt-hours of energy and weighs two hundred and fifty pounds.
Therefore, it takes about one hundred and twenty Powerwall 2batteries, weighing thirty THOUSAND pounds, to hold the energy contained in one barrel of oil.
A Powerwall 2 battery plus mounting hardware costs about seven thousand eight hundred US dollars.
Enough Powerwall 2 batteries to store the energy in a single barrel of oil would cost just under a million dollars US.
Get off of fossil fuels?
Get real!
A QUICK NOTE FROM TIM:And don't forget you have to CHARGE the batteries, which requires more equipment and a power source. You lose energy in the transference to electricity; a traditional generator using natural gas and a combined heat and power system is at best 80% efficient, and that is the top of the food chain. Most systems are substantially less. A simple gas turbine has an efficiency around 42%.
Coal burns around 33%.
A solar panel is 15 to 20% efficient, while a windmill is considered pretty efficient at 30 to 40% although there are new bladeless varieties that claim to be almost 60%. But it is clear there is considerable loss of energy between the original source and it's conversion to electricity.
Then you have the loss of energy in transmission. In the U.S. that rate is about 5%, a not insignificant number. See here.
Of course, you have to use energy to make the batteries, too.
While the efficiency of a gas-powered automobile engine is between 20 and 35% it is a direct conversion. You don't have loss from generating, loss from transmission, and loss from manufacturing. You don't have loss from battery discharge. (Car batteries range in relative efficiency from 50 to 90% depending on the type of battery used.)
So it is clear there is considerable extra baggage when trying to power an automobile with batteries.
Posted by: Timothy Birdnow at
10:22 AM
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I have to admit I don't know how long it takes to recharge a Powerwall battery, from any particular state of discharge. I do know that if you go to one of the new supermarket chains in my area they have a few parking spaces reserved for electric cars, complete with chargers. I would presume owners are charged money for their use. Once in a great while I actually see one in use. And yes, there are a lot of Teslas in this area.
But if I go to any of the local gas stations within a twenty mile radius of my home (and there are a whole bunch of them), unless there's some unexpected problem, I don't expect to wait behind more than two cars to get my turn at a pump -- less if I'm in my Chevy Cruze with its right-hand-size fill port. Generally I can pull right up to a pump. And with either car, utilizing the recommended slow pumping speed, and assuming I'm down to less than a quarter tank, it may take me around five minutes to accomplish the entire transaction. This is pay-at-the-pump and includes writing my odometer reading onto the receipt, folding it, putting it into my wallet (because I log all my car expenses), putting my seat belt on, starting the engine and driving away. OK, maybe seven minutes.
Can you charge a Tesla that quickly?
Posted by: Dana Mathewson at January 26, 2020 03:26 PM (B85Mr)
Posted by: Dana Mathewson at January 26, 2020 11:05 PM (0gBw9)
Posted by: Timothy Birdnow at January 27, 2020 03:32 PM (ejGHA)
And a hybrid may or may not make sense for you depending on your driving patterns. If you putter around town most of the time, they get great mileage, but if most of your driving is on "big" roads, with few stops, fuggedaboudit, they use as much gas as a regular car. And my understanding is that different hybrids out there are designed for different types of driving, though I may have gotten the wrong impression when they first started flooding the market.
Posted by: Dana Mathewson at January 27, 2020 10:09 PM (ten4B)
Too bad you can't find VW Beetles anymore; they would have been great for Cat.
Posted by: Timothy Birdnow at January 28, 2020 07:37 AM (EkXGF)
You have to use synthetic oil, which costs! But you go 8000 miles between changes.
Posted by: Dana Mathewson at January 28, 2020 04:29 PM (pUntP)
Right now Cathy is driving her mothers' old 92 Toyota Camry. It was a nice car once but now is feeling it's age. AC is out, the passenger window doesn't open, there is no passenger side mirror. The paint is horribly oxidized. (Her brother was driving that car when he was caring for her parents before they died). We took the car off their hands because I was in the hospital with my heart failure and our other car just up and died, so they offered it to us - as my father-in-law said, it was no bargain. He was right, and Cathy was driving it with no brakes until I got out of the hospital. But it's been a good car since, largely because we don't stress it. Granted, for some reason the battery died on it a couple of weeks ago and now it's sitting out in our back parking pad. I'm gong to have to get it into the shop some time soon. Or get a new car and get rid of the old gray mare (the car, not Cathy...I'm going to GET IT for that!)
At any rate, we are down to my F150, which isn't as bad on gas as I thought it would be but it certainly can be improved upon. And given my eyesight I really wish I had a smaller vehicle. Oh well; what are you going to do.
Posted by: Timothy Birdnow at January 29, 2020 07:20 AM (Dzyvy)
My late father-in-law had a Camry that I drove a few times almost 20 years ago and I loved it. Last I knew, maybe four years ago, Martha's brother Jim had the car, and I think it was still in pretty good shape except for the paint. Jim's adept at keeping cars running longer than they should normally be on the road, I'll give him that. He and his wife and two dogs were driving cross-country from Oregon and they spent a couple days with us. I think he's finally had to take it to the boneyard; there comes a time when it's too expensive in time and money to keep a car on the road.
Posted by: Dana Mathewson at January 29, 2020 12:29 PM (nYRaQ)
I've got to get it out and to the shop.
I'm not surprised about how well your father in law's treated him. Wonderful cars.
Posted by: Timothy Birdnow at January 30, 2020 07:47 AM (HzfKD)
If it doesn't appear to be an expensive fix, I'd say to go for it. Those cars will go into the 200K mile range easily.
Posted by: Dana Mathewson at January 30, 2020 10:43 AM (wp4a2)
Hope I can fix it; it's been a good little car.
Posted by: Timothy Birdnow at January 30, 2020 12:24 PM (w2HfX)
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