Randy wrote:I’m sorry to learn about your disappointment in the information we provided, but I’m glad you shared it with us
It sounded to me like people were mostly happy with the information you provided. The only disconnect was that some of us thought you were going to announce the new rates, and probably none of us in the audience guessed what was so obvious to you SDG&E folks that you didn't even think of talking about it - that rate setting involves a long regulatory process. So thanks for that clarification here.
The purpose of the workshop last week was to give the Study participants enough time to consider their rate alternatives, and introduce the option of rolling off these temporary experimental rates before the end of 2013, if there was another rate that could save them money.
It's good to have the reminder to consider the alternatives.
In a couple of places in your note, you make reference to getting “soaked” (and other adjectives) by the company, and you have also questioned our EV-friendly stance.
Just as with public L2 and QC rates whether or not the rates seem fair depends on your perspective. Consider: for me changing from the EV-Y rate to EV-TOU would mean a 50% rate increase! Wildly excessive, right? Well... Today my driving cost is 1/4 that of when I drove my Prius (remember a Prius doesn't get 50 MPG on short trips with the engine cold). Your EV-TOU rate would make it 3/8 the cost of a Prius. Is that excessive? Since I have solar I could switch to whole house tiered rates, stay in baseline, and drive for 1/3 the cost of a Prius. If I added more solar panels I might make that cost anywhere from 50% lower to 50% higher depending on which cost estimate I use - the devil is in the details.
And of course long term my driving cost must also include battery replacement cost, which Nissan refuses to tell us. But it's bounded by their $100/month rental offer, which just equals my cost to fuel a Prius, and 4X what I'm now paying SDG&E for fuel.
So I believe this and many other reasons qualify us as being very “EV friendly”.
No arguments here.
Here is a small example of aggregated raw draft data that we’ve collected so far
Thanks for that! That most charging is done at night we had all heard, and read in the EVproject reports as well. What I didn't expect to see was that as time went on people charged more during the day. As you suggested part of that could be the effect of new drivers joining the study. Your data should allow you to determine to what extent that was the case. A few more possibilities occur to me:
1. Getting accustomed) Initially I scrupulously avoided charging during the day because I'd be overpaying outrageously, over 3X as expensive. Talk about getting "soaked!" But wait. If I need a little more range and charge for an hour you're "soaking" me to the tune of about 80 cents, substantially cheaper than driving a Prius. I can live with that occasionally when I really need it.
2. Battery degradation) As our batteries age and lose capacity we're more likely to need to add charge during the day to take us the same distance our new batteries used to do on a single charge.
3. Lagging infrastructure) Say you return home in the afternoon with 2 bars left and are probably not going out again. It's smarter to wait to charge overnight when it's cheaper. But if it happens you do need to make another trip, what do you do? If you can be sure that there will be an available L2 station at your destination or an available QC station conveniently on route then you should still wait to charge, and take care of the contingency only if it arises. But if charging stations are scarce or frequently unavailable then you'd better recharge at every opportunity if there's a possibility you'll need it.
To study 1 you could look at peak/off-peak/super-off-peak ratios over time for each car individually, as I suppose you are doing.
To study 2 you could ask all of us to report our battery status to you, in bars if that's all we know, or in amp-hours or GIDs if we have or can borrow some extra instrumentation. Not everyone would tell you but I bet enough of us would to give you some useful data.
To study 3 you might correlate each car's home charging statistics with its public charging statistics from the EV Project. (I hope that the data release authorization we already made covers use by our utility.) You could say that a driver who charges relatively often at public stations finds the public infrastructure relatively more adequate for his use, than does a driver who charges seldom in public. Do those who frequent public charging stations charge less at home on peak? If so, is their total peak charging (home plus public) less than that of drivers who find the public infrastructure unusable?
