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The biggest problem is peak power. The naïve approach is to try to pull 500kW from the grid during the 20 minutes that you have five cars charging, then zero on

by marvin 6y ago

The biggest problem is peak power. The naïve approach is to try to pull 500kW from the grid during the 20 minutes that you have five cars charging, then zero once they leave. This will at best be very expensive, but most likely impossible as the local grid won't support it. So a battery buffer needs to be built into the charging station in order to operate them cheaply, with a smoother load profile that the power company and grid operator will service without exorbitant costs. Thankfully, at least one EV company has already realized this :-) Let's see if more than one of them eventually starts producing enough batteries to support the strategy.

cptskippy 6y ago
That will be less of a problem than you think. Power demand is already inconsistent throughout the day. Depending on the time of year it will peak around noon or in the evening but overnight the demand is low. When people start charging overnight at home the overnight loads will increase. This will intern allow power companies to increase capacity.
- viraptor 6y ago
  I suspect new payment plans will get more popular soon. I'm not familiar with the US providers, but in Australia there are already at least two companies allowing you to buy energy at a current, hourly adjusted price. I expect that in a couple of decades "energy cost arbitrage via car charging" will be a normal thing.
  - cptskippy 6y ago
    You're probably right. In the US there's generally two systems, flat-rate or time-of-use. A lot of people on time-of-use plans are installing battery backups and/or solar to avoid the peak charges. I have a Tesla solar/powerwall setup that's configured for cost savings and it decided that today 100% of solar was going to be back fed to the grid and we've been running 100% off the batteries. Usually the system just switches to batteries during peak.
    - core-questions 6y ago
      > Usually the system just switches to batteries during peak. You'd think you'd want to be using them more often - is it just that there's no grid demand for the power? My hope is that the addition of a huge number of batteries to the grid, in the form of all these EVs, actually adds to its capacity, since most people won't be running them down to 0 and the software to optimize when to charge vs. when to power the grid seems to be evolving. Pity it's not a nice open source standard or anything
      - cptskippy 6y ago
        I don't know that any EV is capable of providing power from its charge port, but that would be helpful for stranded vehicles. Even if my EV could push power to the grid, I'm not sure I would want it too. It would require me to keep my EV plugged in and topped off which isn't good for the batteries. Currently both my EVs are sitting at around 50% unplugged.
        ascorbic 6y ago
        The Nissan Leaf can https://www.nissan.co.uk/range/electric-cars/v2g.html https://www.nissan.co.uk/range/electric-cars/v2g.html
- marvin 6y ago
  I’m pretty confident that this will work itself out, but you see the problem very clearly in Norway already. Non-Tesla charging stations are much more expensive per kWh due to this, reducing the cost-of-ownership advantage of EVs vs. fossil cars. It doesn’t put the cost in no-go territory, but it’s enough that users feel cheated and complain. So if the established manufacturers or third-party charging providers want to be competitive, they will eventually have to think about this.

by marvin 6y ago

cptskippy 6y ago

That will be less of a problem than you think. Power demand is already inconsistent throughout the day. Depending on the time of year it will peak around noon or in the evening but overnight the demand is low. When people start charging overnight at home the overnight loads will increase. This will intern allow power companies to increase capacity.

viraptor 6y ago
I suspect new payment plans will get more popular soon. I'm not familiar with the US providers, but in Australia there are already at least two companies allowing you to buy energy at a current, hourly adjusted price. I expect that in a couple of decades "energy cost arbitrage via car charging" will be a normal thing.
- cptskippy 6y ago
  You're probably right. In the US there's generally two systems, flat-rate or time-of-use. A lot of people on time-of-use plans are installing battery backups and/or solar to avoid the peak charges. I have a Tesla solar/powerwall setup that's configured for cost savings and it decided that today 100% of solar was going to be back fed to the grid and we've been running 100% off the batteries. Usually the system just switches to batteries during peak.
  - core-questions 6y ago
    > Usually the system just switches to batteries during peak. You'd think you'd want to be using them more often - is it just that there's no grid demand for the power? My hope is that the addition of a huge number of batteries to the grid, in the form of all these EVs, actually adds to its capacity, since most people won't be running them down to 0 and the software to optimize when to charge vs. when to power the grid seems to be evolving. Pity it's not a nice open source standard or anything
    - cptskippy 6y ago
      I don't know that any EV is capable of providing power from its charge port, but that would be helpful for stranded vehicles. Even if my EV could push power to the grid, I'm not sure I would want it too. It would require me to keep my EV plugged in and topped off which isn't good for the batteries. Currently both my EVs are sitting at around 50% unplugged.
      - ascorbic 6y ago
        The Nissan Leaf can https://www.nissan.co.uk/range/electric-cars/v2g.html https://www.nissan.co.uk/range/electric-cars/v2g.html
marvin 6y ago
I’m pretty confident that this will work itself out, but you see the problem very clearly in Norway already. Non-Tesla charging stations are much more expensive per kWh due to this, reducing the cost-of-ownership advantage of EVs vs. fossil cars. It doesn’t put the cost in no-go territory, but it’s enough that users feel cheated and complain. So if the established manufacturers or third-party charging providers want to be competitive, they will eventually have to think about this.