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So to begin with let me be clear that I think using car batteries to time-shift load on the power grid makes some sense (mostly for cars parked at homes). Howev

So to begin with let me be clear that I think using car batteries to time-shift load on the power grid makes some sense (mostly for cars parked at homes). However, it sounds like you're talking about using car batteries for solving distribution over geographical space rather than time, which I don't think makes sense at all. > Why wouldn't I want to sell some of that electricity at a higher price 1) Charging, driving, and charging is never going to be economically competitive with transferring power through transmission lines. 2) Even if you could somehow drive from an area that has chargers connected to power plants to an area that ... has a decentralized off grid charging thing (?), and there's enough density of customers there in this electricity-less place, you can at most sell something like $2 per hour and a reasonable profit is going to be in the tens of cents per hour, max. Then you have to cover expenses: wear and tear on your $20,000 battery, on the rest of your car, opportunity cost of sitting there giving away power, and most importantly the planning and risk involved in driving afterwards with less in the tank.

jaggederest 5y ago
I think you're thinking too large scale. Think of replacing a peaker plant that might only be in operation for an hour by having a city full of cars each supply 100w for that hour. It's 1/800th of a tesla battery, but it replaces $500 worth of peaking plant usage.
- foobarbecue 5y ago
  Yep that makes sense. That's one of the situations I was referring to when I said: > let me be clear that I think using car batteries to time-shift load on the power grid makes some sense Note of course that you could probably achieve something similar by just having teslas be smart enough to stop charging during peak times if the owner OKs it instead of actually discharging full ones.
IanCal 5y ago
Well, you were explicitly asking about that scenario so that's why I addressed it. > 1) Charging, driving, and charging is never going to be economically competitive with transferring power through transmission lines. I can charge at 5p/kWh during the night but during the day would be buying at ~25p/kWh as a regular customer at home - buying from a charger on the road would be more expensive (if nothing else, the VAT situation is different I think). Is it not reasonable to think that it may be more economic to transfer power between two cars near each other than across the country? That's what would be happening if I'm putting back on the grid while someone else is charging their car somewhere. > . Then you have to cover expenses: wear and tear on your $20,000 battery, on the rest of your car, opportunity cost of sitting there giving away power, and most importantly the planning and risk involved in driving afterwards with less in the tank. I think you're picturing explicitly driving to a car park to sell excess power. That's not what I'm talking about. I'm saying that going to the shops/work and plugging in my car, it may easily make sense for my car to sell some of that electricity to someone else as I'm not going to need it today and can charge up at night cheaply. There's no wear & tear on my car, and no opportunity cost about sitting there. Wear & tear on the battery is identical to any other load shifting, home battery or car, so if it doesn't make sense to do in the car park it wouldn't make sense to do at any other time. > and most importantly the planning and risk involved in driving afterwards with less in the tank. That's what the commenter was talking about with some smarts on trip planning. Frankly for most people long trips are rare enough that a default "leave me with X in the tank unless told otherwise" would deal with almost everything.

jaggederest 5y ago

I think you're thinking too large scale. Think of replacing a peaker plant that might only be in operation for an hour by having a city full of cars each supply 100w for that hour. It's 1/800th of a tesla battery, but it replaces $500 worth of peaking plant usage.

foobarbecue 5y ago
Yep that makes sense. That's one of the situations I was referring to when I said: > let me be clear that I think using car batteries to time-shift load on the power grid makes some sense Note of course that you could probably achieve something similar by just having teslas be smart enough to stop charging during peak times if the owner OKs it instead of actually discharging full ones.

IanCal 5y ago

Well, you were explicitly asking about that scenario so that's why I addressed it. > 1) Charging, driving, and charging is never going to be economically competitive with transferring power through transmission lines. I can charge at 5p/kWh during the night but during the day would be buying at ~25p/kWh as a regular customer at home - buying from a charger on the road would be more expensive (if nothing else, the VAT situation is different I think). Is it not reasonable to think that it may be more economic to transfer power between two cars near each other than across the country? That's what would be happening if I'm putting back on the grid while someone else is charging their car somewhere. > . Then you have to cover expenses: wear and tear on your $20,000 battery, on the rest of your car, opportunity cost of sitting there giving away power, and most importantly the planning and risk involved in driving afterwards with less in the tank. I think you're picturing explicitly driving to a car park to sell excess power. That's not what I'm talking about. I'm saying that going to the shops/work and plugging in my car, it may easily make sense for my car to sell some of that electricity to someone else as I'm not going to need it today and can charge up at night cheaply. There's no wear & tear on my car, and no opportunity cost about sitting there. Wear & tear on the battery is identical to any other load shifting, home battery or car, so if it doesn't make sense to do in the car park it wouldn't make sense to do at any other time. > and most importantly the planning and risk involved in driving afterwards with less in the tank. That's what the commenter was talking about with some smarts on trip planning. Frankly for most people long trips are rare enough that a default "leave me with X in the tank unless told otherwise" would deal with almost everything.