Better Place and PJM Interconnection looked at the effect of putting 1 million EVs into service in the areas around Washington DC.
I know for many people thinking or discussing cost of power transmission/generation is right up there with watching paint dry. But we are in the midst of revolution in transportation, and a key component of that revolution will be the systems and habits we establish for charging those EVs.
They considered three scenarios.
Unmanaged charging: where you basically just plug in whenever you feel like it. I am doing that right now. It is very convenient. ? However, I recognize that when EVs are widespread, this is not going to be good for the grid.
Time of Use (TOU): where you pay a higher rate for on peak use and a lower rate for off peak use.
Central Network Operator: In this scenario batteries get charged based on six criteria.
1. Energy needed for next planned trip
2. Time until energy is needed
3. Battery state of charge
4. Time of Day
5. Predicted local marginal pricing (this would be the actual cost to generate/transmit the power at that time of day).
6. Actual localized marginal pricing
Big picture. Better Place is the company whose vision of the EV future is one where instead of driving your car into a garage at night and plugging it in, you drive your car into their Battery Switching Station, and they pull your depleted battery and replace it with a freshly charged battery. PJM Interconnect manages wholesale grid transmissions.
I have to admit a personal bias. When I thought about EVs I always thought “won’t it be cool not to have to go to a gas station. I can just drive home and plug it in. Voila.” And after driving a Volt for 10k miles, it turns out yes it really is convenient to plug it at home. Not dealing with the hassle of a gas station is definitely a bonus with an EV. Plugging in the Volt literally takes 5 seconds.
Because they were calling them Battery Switching Stations, I initially thought this study was talking about installing facilities at Power Sub Stations where batteries would store power (presumably charged off peak) and then distribute it during peak hours as needed.
But it appears they are just talking about their vision where they charge batteries at night and when yours is depleted during the day you come to them and get a fresh one.
There may be a market for that, apartment residents come to mind, but on the whole, most people are going to want the convenience of simply charging at home. So far the pricing schemes for this service is very significant.
Also this BSS battery vision assumes air cooled batteries. Towards that end Renault and Nissan have made a go of batteries that are NOT thermally regulated. It has been suggested that part of the Leaf’s range estimation problems have to do with the lack of thermal regulation. Shortly, after introducing the Leaf, Nissan made thermal regulation of the battery an option for US cars, and it was made standard on Canadian cars. It remains to be seen if “air cooled” batteries are actually viable. Obviously Ford, and GM have concluded otherwise.
The study states that adding 1 million EVs could add $750 million in wholesale electrical costs per year. Umm yup. That’s $750 per car. Probably a little high, I am on track to do about 18k per year in the Volt and that will cost me about $540 based on my electrical rate of 10.3 cents/kwh.
But the point is if you add 1 million of anything electrical it will not run for free. News Flash “1 million electric water heaters will add $500 million to electric generation costs!”
What the study does bring up though is this notion of smoothing out the demand curve during the day by taking those 6 CNO criteria and having smart meters that work with the grid and individual EVs to either delay charge or charged at a reduced rate, when doing so is compatiable with the next planned trip.
Looking at Fig. 7 we see that there are two peak charging times. First around 9am when everyone gets to work and again around 5 pm when everyone gets home. For the person who does not go anywhere during the day, there is no need to commence charging at 9am if they are not going to drive anywhere until 4pm. Or even if the person goes out at lunch if their commute is such that charging could be started at later time and still complete without disrupting the needs of the owner then we could smooth out demand.
How we make that happen is the question. How do you get an owner to take the time to factor all that in, instead of just plugging in and charging willy nilly?
TOU is one possibility. But could TOU alone accompolish the above? Interestingly the Study concludes that TOU actually ended up costing more to generate power than if drivers simply used unmanaged charging. Seems hard to believe since TOU charts show demand being moved off peak.
The UK is considering auction prices for the high demand times.
GM has made delayed charging a built in function of the Volt, but that requires the driver to program the vehicle, I am skeptical that owners will do that unless there is a significant cost benefit to doing so, or the process is more automated.
Automated as in the car asks me either in the car, or perhaps through an app “delay charging till 10am to receive a discounted charging rate? Y or N?”
The grid can handle the load of EVs coming down the road, but we have an opportunity to achieve that integration in way that saves billions of dollars both for the power companies and for consumers. Hopefully, profit motives of individual companies will not interfere with the most efficient system of integration being selected.
thetruthaboutcars.com reaches a different conclusion. You can read that post here:
http://www.thetruthaboutcars.com/2011/0 ... ar-jungle/
http://www.betterplace.com/uploads/ckfi ... -publisher