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Charge by the hour vs. by the kWh

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by F8L, Jun 21, 2013.

  1. F8L

    F8L Protecting Habitat & AG Lands

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    I was performing calculations to try and determine a fair rate for the owners of our business park to charge for EV charging. In doing so I quantified something we all intuitively knew but it was stunning nonetheless.

    In some states you are not allowed to charge for electricity by rate or kWh. This leaves an EV charging station owner to charge a flat rate, charge nothing or charge by the hour. Charging by the hour can really screw up your financial calculations because some cars charge much faster than others on the same 240v source.

    For example, the 2011 Nissan Leaf has an onboard 3.3kW charger whereas the 2013 model has a 6.6kW onboard charger. Charge times in a 240v source drop from 7 hours to 4 hours. That essentially doubles the cost per mile for a 2010-2012 Leaf owner if they had to pay by the hour!
    For the Prius Plug In, the cost per mile for gasoline is so low that even at $1/hr for a 1.5hr charge is almost doubling the cost per mile. In this situation you are much better off just using gasoline. The Honda Accord Plug In has a faster recharge rate so it only takes 35min or so to recharge its slightly larger battery. In this case the $1/hr rate is acceptable for the Accord. * In the table I used Honda's claim for 1hr charge time despite what I've read on the forums.Here are the rough numbers I am working on. Please excuse the errors. I was only aiming for ballpark figures to show examples to our building owners. Cost to recharge = pay by hour. Cost to recharge2 = pay by kWh.

    Ev vs. Gas.jpg
     
    Jeff N, retired4999, iplug and 3 others like this.
  2. usbseawolf2000

    usbseawolf2000 HSD PhD

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    In that case, they should make PiP free to charge then. :)
     
  3. Drake

    Drake Junior Member

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    Lol, I thought that only our politicians in QC (Canada) were stupid enough to disallow the charge for electricity by rate or kWh.

    Here, we usually have to pay a 2.50$ flat rate for a charge which is ridiculously high for Plug-in Prius owners but a very good deal for a 85KWH Tesla Model S owner with an empty battery. It cost me around 20 cents to charge the PiP at home.

    This is a stupid old & outdated law IMO.

    This is even funnier considering that they put these charging station in places where you can easily spend less than an hour. (i.e. hardware stores, groceries, etc.) I would use it a lot if the price was lower but at that price, I don't even have a membership card.
     
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  4. Zythryn

    Zythryn Senior Member

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    Agreed, charging a flat fee is silly.
    Charge by kWh is much simpler for the consumer and much fairer as well.
     
  5. mrbigh

    mrbigh Prius Absolutum Dominium

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    I will use your chart for the EAA NY chapter as an example
     
  6. iplug

    iplug Senior Member

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    Thanks for putting this together. I am assuming since you are in California, our laws allow charging per kWh, no?
     
  7. frodoz737

    frodoz737 Top Wrench

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    If I may ask, where do these laws apply and any knowledge or speculation as to why?
     
  8. San_Carlos_Jeff

    San_Carlos_Jeff Active Member

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    In my mind charging stations need to be a mix of hourly rate and usage. If I owned a charging station it wouldn't make sense to have a 2010 Leaf hogging the spot for twice as long as a 2013 Leaf and paying the same amount. There also has to be a financial incentive to make people move their cars after charging is complete.

    It might not be fair to all but off the cuff I'd say that once you plug in the rate should be charged for usage, but at some predetermined minimum rate. Then when charging is complete there would be some sort of grace period and then it would kick into an hourly amount that is higher than the local hourly parking.


    For example:

    Inital Plug in: Rate is for 5kwh charge or whatever your vehicle is drawing (whichever is higher)
    After charge is complete: 20 minute grace period of no $$.
    After grace period is over: Hourly rate of $x/hour where x is enough to make people move their cars

    -Jeff
     
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  9. San_Carlos_Jeff

    San_Carlos_Jeff Active Member

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    Don't know where, but they "why" is because utility companies want to hold on to their monopolies and prevent competition so they bribed (some might say lobby) politicians to pass laws like these.
     
  10. frodoz737

    frodoz737 Top Wrench

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    Though it may be easy for me to believe politicians and Utilities the culprits, some places more so than others, facts are what I seek.
     
  11. CharlesH

    CharlesH CA HOV Decal #5 on former PiP

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    The "why" is that the lobbyists got the law written so that selling by the Kwh made you into a electric utility, subject to all regulations that apply to such providers. When charging by time, you are just buying connection time, which just incidentally hopefully involves some electric power. These laws long pre-date EV charging stations. I believe that California recently rescinded this interpretation for EV charging stations, so EV charging stations here can charge by the Kwh without being considered utilities.
     
  12. frodoz737

    frodoz737 Top Wrench

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    Assuming California rescinded this law, are we talking federal law....as it applies to where?
     
  13. Jeff N

    Jeff N The answer is 0042

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    As it happens, I'm meeting with someone at ChargePoint (Coulomb Technologies) later today to discuss these kinds of issues. I will mention this thread.

    Here's an interesting article where their CEO discusses this issue:

    Proceed with caution: charging for EV charging | ChargedEVs

    Here's a detailed 50 state report that was published in March 2013 that includes the status and legal basis for charging per-kWh:

    http://www.theevproject.com/cms-assets/documents/103425-835189.ri-2.pdf

    ChargePoint added a lot of flexibility for pricing policies in their ChargePoint 4.0 software update that came out about 9 months ago but few station owners are taking advantage of it yet. There are also some sensible policies that they don't support yet which I plan to discuss with them.
     
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  14. F8L

    F8L Protecting Habitat & AG Lands

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    California passed AB631 which allows owners of charging stations to sell by kWh. You would have to have a way of monitoring the draw though. At my work they don't want to install meters.

    Until we come up with a better idea we are going to on the honor system for tenants and charge $.50/hr. That normally wouldn't work well for a PIP but since I helped set it all up I get special concessions. :)

    I'll see if I can find a list of states that allow the owner to choose how they want to charge.
     
  15. Jeff N

    Jeff N The answer is 0042

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    This info is in a table inside the "50 state" report that I linked to in a post a few minutes ago.
     
  16. F8L

    F8L Protecting Habitat & AG Lands

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    Thanks Jeff! I missed it between slamming down some Taco Bell lunch. ;)

    Anyone wanting to use the chart I posted should be advised that my numbers for usable charge and such are the best I could find with little research. Feel free to use the chart as a guide to develop your own chart with more accurate numbers. I won't be able to update mine until I get back to my computer on Monday.

    Ohh and FWIW, I talked to the owner of the Accord Plug In today and she confirmed the speculation that the battery charges very quickly and she is reading 17miles displayed range after a charge. She said it read 15miles when they first bought the car. Gotta love those on board 6.6kW chargers!
     
  17. JamesBurke

    JamesBurke Senior Member

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    Only 49 states in the EV union because WV seceded. The meter needs to be utility grade calibrated for accuracy. Not sure how the areas RV parks handle their electrical hookups probably flat rate.
     
  18. CharlesH

    CharlesH CA HOV Decal #5 on former PiP

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    I can see the metering issue if what is provided are simple 120V outlets that the EV owner plugs their own EVSE into. Charging stations like from ChargePoint and Blink have built-in metering.
     
  19. F8L

    F8L Protecting Habitat & AG Lands

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    A lot of stations around here are Clipper Creek units.
     
  20. Corwyn

    Corwyn Energy Curmudgeon

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    I am not convinced about fairer. The business has two costs, actual electricity, and space availability (opportunity cost). A car which takes much longer to charge to the same level (kWh) is taking up a space that a faster charging car would be providing more income.

    Once there is competition in charging stations, places charging by the hour will be visited by people with fast charging cars, and places charging by the kWh, by slow charging cars. This seems unlikely to be optimal.

    If I were running such a station, I would charge a fee for electricity, and another fee for length of time IN THE SPACE (charging or not). Weighting those fees would require some empirical data.
     
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