July 13, 2010
Home Electric Upgrades For Electric Cars Part II

Nissan finds bureaucratic obstacles for home electric power upgrades pose problems for the roll-out of their all electric Leaf car.

But if you want to use the full range of your electric car, it could take over a day to recharge using a standard 110-volt power outlet.

The point was driven home Monday in an article in The Wall Street Journal, which described Nissan's efforts to break through bureaucracy to make it easier for homeowners to get special electric vehicle charging stations installed. Nissan, which is coming out with an electric vehicle this year called the Leaf, is concerned that customers will be put off from buying the car by the 20 hours required to recharge it from a standard outlet to get its full 100-mile range. Currently, it can take weeks for cities to issue the necessary permits for a fast charger that can cut recharging time to eight hours, the article said, and the price for the special charger, including installation, will range from about $1,200 (with a tax credit) to several thousand dollars if a electric panel upgrade is needed.

I've also covered this previously in my post Home Electric Upgrades For Electric Cars.

Who is the ideal Nissan Leaf electric car driver? Imagine you have the lifestyle characteristics for maximum ROI from driving an electric car. What does that the commuting pattern of that lifestyle look like?

  • Long distance commuter. Ideally 90 miles in each direction. Run down that battery twice a day for faster return on investment. We can pity the person who has to do this much daily commuting.
  • Own a house that you expect to live in for many years in order to recoup the cost of the electric wiring upgrade to 220V high amp power.
  • Got a garage where the car will park every night with electric power cord coming down from the ceiling.
  • Got a very stable job where they are willing to supply your car with 220V high amp plug-in (again, parking in a covered garage) to recharge while you work.

Then if you go to work 250 days a year (quite the work-aholic) you travel about 45000 miles per year purely on electric power.

Okay, what's your best pure gasoline alternative? The Toyota Prius at about 50 mpg. Choosing a Leaf over a Prius would mean 900 gallons of gasoline avoided per year. Let us imagine that gasoline prices go back up and you pay an average of $4 per gallon for 5 years driving either the pure electric Nissan Leaf or hybrid Toyota Prius car. The Leaf lets you avoid 3600 gallons of gasoline for $14400 saved. But you have to subtract off maybe 250 watt-hours of cost per mile for the Leaf recharging. Say 2.6 cents per mile (it'll vary depending on where you live) or a total of $4680 for 5 years or 225000 miles of electric power. That yields a total savings of $9720. Given that the electric car's added cost is higher than that (I'm ignoring the cost reduction due to tax credits since somebody pays for the higher cost) you can see that electric cars take 5+ years to pay off for the really rare very high mileage drivers.

Of course I chose the ideal electric car driver to sketch out an ideal amount of money saved. In reality the average commuter is traveling less than half that distance per day and takes off more than 2 weeks for vacations, holidays, and sick time. So payback time is much longer, easily over 10 years. Plus, more money paid up front for a car is an opportunity cost since the money shelled out can't be invested elsewhere for a healthy ROI.

Most people do not match the ideal electric car driver profile in other ways as well. Renters aren't going to upgrade their apartment's or house's electric power. Until electric cars become extremely common not many landlords will invest in the upgrades either. People who see their house as a temporary abode for a few years until they move up or get transferred in their job similarly won't put in the 220V electric power. Ditto for people who are underwater in their mortgages (about a quarter of US mortgage holders last I checked). A suitable place to plug in at work with 220V and high amps is going to be even more rare than home 220V.

Another point: dynamic electric power pricing (which is going to become more widespread) will increase the cost of daytime recharging while lowering the price of night time recharging. So if your commute is so long that you need to recharge while at work your electric power cost per mile will be higher than if you only recharge while at home. So the ideal scenario of 2 recharges per day is really not as attractive as I sketched out above. The spread of wind power (which blows stronger at night) will widen the price gap between wholesale electric power prices from peak to bottom.

Also, if you will want to recharge your car when electric power is cheapest you'll need higher amp 220V power so that you can delay the start of recharging until after about 9 or 10 PM in order to get cheap late night electric power rates. But you'll have to weigh the difference in electric power costs versus the cost of electric wiring upgrades.

If you could jump into a time machine and come out 40 years from now you'd see a society where the shift to electric power for transportation has already happened and the cost problems outlined above are a faded memory. Battery cost drops, cheap solar photovoltaics, new houses built with 220V power, and other adjustments will enable much wider spread use of electric power for transportation. Peak Oil will help to accelerate the transition, meaning that many of the adjustments will happen under very trying circumstances.

One upbeat way to look at the costs of an electric car: Price insurance. If oil is going to back up near $150 per barrel and beyond (and I think it will) then an electric car would put a ceiling on your transportation costs that would let you adjust more easily to Peak Oil.

Update: Note that in my analysis above the high mileage driver can get a return on the EV investment. But the number of miles needed to get that return (ignoring tax credits) is so high I wonder whether the batteries will wear out before returning their costs. The Chevy Volt battery warranty will be 100,000 miles or 8 years.

But note that if you play the rational actor responding to the incentives created by tax policy then an EV pays back very quickly. Given the tax credit a Nissan Leaf will cost at most $1k more than a Prius (unless Toyota starts discounting). You get into the black pretty quickly on your investment. The Leaf and the Chevy Volt are both worth a serious look.

I expect the economics of PHEVs and EVs will become more favorable due to a combination of declining battery costs and rising oil costs. But electric cars have to fall by over $7k just to compensate for the eventual phase-out of EV and PHEV tax credits.

Share |      Randall Parker, 2010 July 13 10:12 PM  Energy Electric Cars

Fat Man said at July 13, 2010 10:55 PM:

"If you could jump into a time machine and come out 40 years from now you'd see a society where the shift to electric power for transportation"

No you won't. Joules = Watts * Seconds = Volts * Amps * Time. You can't get around it.

If we run out of fossil fuels, we will replace them with manufactured hydrocarbons. That has been done before.

Engineer-Poet said at July 14, 2010 7:17 AM:

Manufacturing hydrocarbons isn't getting much cheaper, and it's horribly inefficient (50% or less); mine-to-wheel for CTL is going to be less than 10%.  Batteries are the major cost of an EV, and both they and the electronics are getting cheaper very rapidly. amd evem with old crappy coal plants the mine-to-wheel is going to be at least twice as good.  Then you've got wind and nuclear, which are cleaner, have no supply issues and are effective insurance against carbon levies.

The pure EV may take a back seat to the HEV and PHEV for a while, but cheaper batteries and the sub-$1-gge price of electricity will not be denied.

Nick G said at July 14, 2010 11:55 AM:

A few thoughts:

The $25K price for the Leaf is indeed realistic: it's what people pay now with the credit, and it's what people will pay in a few years with economies of scale. $25K is roughly the price of the Prius currently - you might pay $1K more for the Leaf. That will pay back very quickly.

If your employer provides power, you can drive 180 miles per day, not 90. What about fleet drivers, who use the vehicles for two shifts per day?

Some people are willing to figure in external costs, like pollution. I think the parents of a lot of soldiers in Afghanistan might be interested.

The average person only drives 30 miles per day: that would only take 6 hours of charging, avoiding the need for a 220V charger, and allowing the use of the lowest night time rates.

Nick G said at July 14, 2010 11:57 AM:

Also, California and Georgia provide another $5K credit. People there can get a Leaf for $20K!!

Nick G said at July 14, 2010 12:00 PM:

Let me address the market price vs real price question again:

If we look at market prices paid by buyers, we have to include the credit. If we want to look at actual system-wide costs, we have to include external costs like pollution, supply security, etc. Either way, the lifecycle cost of the Leaf is much less than the cost of an ICE vehicle, including the Prius.

Randall Parker said at July 14, 2010 5:53 PM:

Nick G,

90 versus 180 miles per day: My bad. I totally blew that one. So someone has to spend 1.5 hours each way in their commute at 60 miles per hour. I reworked the math and fix the post. Does the math make sense now?

Average person driving 30 miles per day: Sure, slower recharge works for them. But they also save much less per day.

$25k for Leaf: Only after tax credits. Now, if the real costs fall to $25k then, sure, a Leaf makes great sense.

But the rational actor responding to the tax credits who does not drive long distances really would benefit from the Leaf. Given the tax credits someone who is going to buy a new car might as well shell out $25k for the Leaf or buy a Chevy Volt rather than a Prius.

So Nick, are you going to buy a Leaf? You live in SoCal, right? $20k. Going to shift from a Prius to a Leaf?

Fat Man,

I share E-P's skepticism about synthetic liquid fuel costs. The conversion efficiency is too low. If battery costs drop sharply then electric cars look like contenders.

Engineer-Poet said at July 14, 2010 8:28 PM:

I'm skeptical about the multi-week delay for building permits.  One, I doubt very much that most cities require a building permit to put in some conduit and pull wire (perhaps NYC and Chicago, with their trade-union lock on such work, do).  Two, the delay for getting delivery of the car should still be quite a bit longer than permit+installation.

If it was my garage, I'd do the work myself.  It's nothing I haven't done before without incident.

Hartree said at July 14, 2010 9:36 PM:

From what I've read, a level 2 charging station is specified at 208-240V at 40 amps max, 32 amps continuous. Whether your existing home electrical system can handle that depends on several factors; service amperage, existing continuous load, and existing max load, how well balanced the load is, condition of the various connections, etc.

Just as a rough guide, my house is a 97 year old 9 room two story with gas heat, no central air, all electric appliances, and a 220V, 100 amp service installed in the mid 60s. I'd consider that pretty marginal for being able to install such a charger. An upgrade to a new 200 amp service and checking any existing connections used would make it more than adequate.

Usual disclaimer: check with local codes/electician/whatnot.

Engineer-Poet said at July 15, 2010 6:45 AM:

Without A/C and running the charger at night (no electric stove or dryer operating at the same time), 100 A should be plenty.

Engineer-Poet said at July 15, 2010 8:22 PM:

Come to think of it, 100 A with a smart charger which limits maximum demand should be fine no matter what you're running.

hartree said at July 16, 2010 3:10 AM:

That's why I said it would be marginal, Engineer-Poet. It assumes knowledge and ability to control use on the part of the homeowner. I could get away with it as I'd watch what else was on, and make sure that any 110V loads were reasonably balanced. What's fine for a single informed user won't be what's needed for the general case. Most households have multiple people that won't be thinking about what the total loading is farther than noting if the breaker trips or not.

You also wouldn't be leaving much capacity for installing anything else that takes large current in the house.

If you have a charger that monitors the whole house current and adjusts accordingly then you'd have less problem, but even then, a steady fairly high load in the rest of the house is going to limit the amount of charge that gets into your batteries. I'd not seen specs for any that did that, the ones I looked at just gave a continuous and peak draw rating.

Regardless, loading a house up to possibly near the rating of the service, especially if the wiring is old, such that the connections may be high resistance isn't a great long term idea. Better to put in a service and wiring that can handle it under non-ideal conditions.

Engineer-Poet said at July 16, 2010 5:28 AM:

220 V at 32 A RMS and power factor 1.0 is 7 kW.  A full recharge of a 25 kWh battery takes about 3.5 hours at this rate.  With typical night-time loads, you could run 2 of these at the full average rate without overloading a 100 A circuit; if you throttled them back to 50%, you accommodate an electric stove and multiple window A/C units operating simultaneously without breaking a sweat.  That would still complete a full charge overnight with time to spare.

The Smart Grid is here already.

Nick G said at July 16, 2010 9:53 AM:

The Volt battery is designed to still have full range at the end of the warranty period. Given the conservatism of the design (only 50% depth of charge, and extremely careful charge and temperature management), I expect it to last the life of the car. Perhaps after 20 years of hard driving the battery life would become inadequate to be useful.

The Leaf isn't as carefully designed - the depth of charge is deeper, and the charge and temperature management aren't as careful. I think Nissan expects very steep declines in battery cost - they aren't leasing the battery separately, but they are pushing conventional whole-vehicle leasing.

Randall, you asked separately about battery range in the Leaf - I think the numbers you referenced are a bit low, but I do think that getting range of 100 miles will require very careful driving, and some drivers will be disappointed. I think that pure EVs will be a niche market in the US for quite a while, though the niche will be significant. Better Place in countries like Israel and Denmark will be very interesting to watch.

I think there's no question that EV costs will fall pretty quickly with volume: the cells in the Leaf cost roughly $8,400, and the pack structure and controls might be another $2,500. Subtract that from the $33K price, and that leaves about $22K to cover the rest of the vehicle. Well, an EV without the battery is a pretty simple, cheap thing to build - much cheaper than an ICE vehicle. You could probably sell it a profit (at large volumes!) for $12K. Now, the cell cost is indeed likely to fall fairly quickly - I think we can expect no more than $6k in less than 10 years. That gives a price of well below $20K. The Volt would be perhaps $2K more: smaller battery, but you have to include the small ICE generator and supporting equipment.

Will I buy a Leaf? Sadly, I don't live in CA; I won't need to buy another car for at least 3-4 years1; and I need a more flexible car, like the Volt.

1 I tend to keep cars for 10-20 years. I just had to replace the 2nd car, which was 20 years old, because it was crushed by a falling tree in a windstorm!

Nick G said at July 16, 2010 10:03 AM:


No superscript support?

Engineer-Poet said at July 16, 2010 9:40 PM:

The tradeoff of short-lived batteries vs. price drops with production is one reason I mourn Firefly Energy.  They had a really great, potentially cheap product that would have been great; even if you had to replace it every few years, it would still have only been about as expensive as today's Li-ion and you could defer the payments until you needed a new battery (and some people might be quite happy with 20 miles of range).

Randall Parker said at July 17, 2010 10:30 AM:

Nick G, I did not know that. I use whatever are the MovableType defaults. I'd like to allow more HTML tags in comments if I could figure out a way to enable it.

Engineer-Poet said at July 17, 2010 8:29 PM:

I just did some searching for info on MT comment filters and came up empty-handed.  They certainly don't make it easy to find details like that.

Randall Parker said at July 17, 2010 10:33 PM:


I think I'll have to hack the MT Perl scripts. I've done this before. But lately my hours at work have been so long that I barely have time to blog, let alone hack my web site. I'll upgrade MT in a month or two and then put in a support ticket on how to do this.

Engineer-Poet said at July 18, 2010 7:59 AM:

I just downloaded MT but I haven't had time to look at it yet.

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