KWh/ Mile? Justifying 19 cent KWh electric rate

This is my rate. Since the prime allows us to schedule the charging time i start it at midnight to get the cheapest rate. Based on smud's my energy tool the avg energy it takes to charge my prime is 1.5kWh X (4 or 5 hrs) (depending on depleted charge) @ $.0717 per kWh equates to an avg of about 50 cents a charge. i usually dont deplete to 0% because my avg daily commute is around 20 miles. So for me its roughly $0.50/20 miles = $0.02 per mile on EV. Cant beat that.

 

A couple of data points

When in HV mode and on a short trip, the ICE has to warm up and you'll may get only about 25 mpg for the first ~5 min (depending on weather). You often spend time idling at stop lights during the mandatory initial warmup. An advantage to the Prime if you have lots of short trips.

On long hilly trips you have a much larger battery to capture regen going downhill.

On the PIP I calculated the charging efficiency over a week or so of L2 charging everyday with no gas usage, except one mandatory startup at 124 miles. I compared the Chargepoint reported kwh delivered to the car reported kwh consumed. The difference was about 9%.

In all driving conditions, if you have at least a few miles of range in the battery, by manually selecting EV mode or not, you get to choose the most efficient energy source. EV for slower or stop-and-go, such as at the start and end of a longer trip and HV mode for highway and higher speed driving.

Mike

 

How do you avoid getting clobbered by the summer evening rate ?

 

I charge my PIP at work and sometimes when out if a charger is available. So far all public chargers I have used have been free. Even if it was slightly higher then gas I prefer EV. We pay about 10 cents a kWh and last week I paid $1.92 for gas at Costco.

 

Is there even a V in the future?

One way to look at the calculations is to look at your MPG monitor.

For example, in my PiP:

• This morning was a 50 mile commute.
• I got 59 mpg (dead winter mind you).
• Gas is $2.19 - so I theoretically spent $1.86 on gas
• However, charging was 2.6 kWH - so I spent about $0.39 on electric with a total trip cost of $2.25

Now in my regular 3rd gen Prius, in freezing temperatures I would have probably gotten 45 mpg.

• So theoretically my cost of gas is $2.43 at 45 mpg, or if I was even babysitting it and able to get 48 mpg: $2.28
• But, my energy is solar and it has offset my use so in fact I'm looking at $1.86 spend vs $2.43 which is saving me $0.57 per day.

I actually do save more because I can charge on the other end as well.

Now just for fun I wanted to play around with the idea of the prime.

• Maybe I do get 79 mpg on the same 50 mile commute, same driving style.
• Gas would be (at $2.19 per gal) $1.39 - saving me $0.47 further per one-way trip over the PiP and $1.04 per one-way trip over the regular Gen 3.

This is all of course theoretical. I saw somewhere a person getting 75 mpg on a 100 mile commute for the Prime so it could be that I may top 80+mpg or so.

It's just that 5th seat issue for me lol...

But, because there is a Pacifica Hybrid Plugin on the horizon I can justify a Prime a little bit more.

 

Haha just going to have to suffer for those few hrs in the summer. Again i dont charge the prime until midnight so that rate stays at 7 cents per kWh all year round.

 

Are you on a TOU plan? What do you pay to run air conditioning during the day?

 

California gives free HOV to Prime, but not hybrids, so it is somewhat common there to not plug-in a PHEV. Plug-In is something you should get if you are committed to plugging-in for quality of EV drive mode or other personal eco-conviction. Prime is a classy commuter car too, but you give up cargo space. Outside CA, I assume pretty rare to get a Prime with no interest in using the Plug-in feature. With the high MPG of Gen4, it's pretty hard to make a cost/eco justification against it.

If you do want a plug in, I agree cost to consumer is low right now with incentives and discounts.

 

Maybe that's extra incentive to have less cargo space...Because you can only carry 4 people, so how much luggage/space would you actually need for a trip? lol. Maybe Toyota thought of this well.

 

I'm sure you ran the numbers but I have to admit that I'm surprised that the TOU works to your money favor:

I figure you consume (rounded):
5 kWh a day at 7 cents a kWh
20 kWh a day at 14 cents a kWh
Summer cooling at 30 cents a kWh

So even before summer cooling you pay an average rate of 12.6 cents a kWh. Is that so much less than non TOU ?
If you had some PV to net meter the day you would be golden.

 

Since you opened this can, allow me to expand my comment:

Electricity has the following benefits over oil:

• Money stays in the country and benefits the economy
• Oil countries that cause the US problems end up with lower revenues
• Less US demand for foreign oil reduces US military adventurism and resource wars

So if electricity is no more expensive than oil, other benefits you may subscribe to should make this an easy choice.

 

On my volt ev mode is also just a more enjoyable driving experience, once you drive silently you will be willing to pay a little extra to keep that experience.

Also ev is Much more efficient than gas in stop and go and at low speeds even at 19 cents a kw you can still probably beat the gas price per mile in stop and go and at low speed driving

 

It's not uncommon for me to average 75-100mpg in my conventional Prius in stop-and-go traffic.

 

Then on ev you should have a range of about 60 miles, electric is MUCH easier to hypermile than gas

 

That's considered a bad day in a plug-in.

 

I have results similar to Jay and hope for about 30-35miles from the Prime on a full charge in light city driving.

 

Assuming 1/3kWh/mi wall-to-whell at 19c/kWh all in that's 6 1/3c/kWh. If underlying gas price (ignoring gas tax*) is around $1.70, then absolutely, electricity will be more expensive.

But:
- Driving electric is a better experience than driving using gasoline
- Unless the temperature drops below 15*F you'll avoid a bunch of cold engine starts that are particularly inefficient. With low gas prices and expensive electricity it's liable just to narrow the price gap, but it narrows the gap.
- The ability to blend can help your overall fuel economy on trips by allowing the car to be easy on the engine.
- Look into TOU. If available, it can make a big difference to marginal charging costs. (It lowers mine by over 2c/kWh).

* Avoiding gas tax payment is a subsidy that could easily disappear.

 

Yes TOU plan i just enrolled and it is winter time so i dont know how its going to be when i start using ac. Im not really home at summer super peak hrs anyway so i factored that into my option to go for that plan

 

I will have to wait and see to compare the difference but since im not really home during summer super peak hrs im hoping it will save me $$ on avg. The fact is its costing me 2 cents a mile! If/when gas goes up it will offset the cost even more. Plus i just received a $300 rebate check from smud for EV owners. Im also waiting on the clean vehicle rebate app to be processed so thats another $1500. All these things factored into my decision to get the prime over the regular hatchback

 

Just curious, did you have the option for an EV Submeter?
In our area, many of the electric coops offer a deal where your house can be billed normally, while a submeter on your garage allows for a TOU rate on just your car, while the rest of your house has normal rates.