Toyota to pursue plug-ins

Rhetorical question: will there be cost-effective conversions easily available for present Prii owners or should we look forward to upgrading to the PHEV model?

I have not considered an EV upgrade at this point because of warranty considerations, new Lithium batteries with greater capacity and more rapid recharge rates coming down the line and other options.

 

The $10,000 question, for sure.

As much as it pains me to say so, I suspect that if Toyota comes through and offers a decent plug-in in 2009, a trade-in is going to be the way to go.

 

I've now run the 2001 National Household Travel Survey numbers correctly, stringing together the legs of trips from home and back to home, and including open-ended (e.g., vacation) trips. The results, when finalized, are only modestly different from my "rough cut" earlier today.

My rough estimate for the arithmetic average length of a car trip was 9.3 miles, consistent with the published US government data. I believe this is the data source from which we all believe that much of US driving consists of short trips. Per the NHTS definition, a trip is what I would call one leg of a round trip, ie, home to work is a trip, work to home is a separate trip.

But the important consideration for PHEV operation is the round-trip distance from home back to home, under the assumption that there's not going to be any (or very limited) opportunity to charge the PHEV battery pack anywhere but home. (For Northern Virginia, this would seem to approximately correct. Californians might have more opportunity for mid-day recharging, in which case these numbers would be too pessimistic for you.) Or, if the car does not return home that day (e.g., vacation travel), total travel distance for the day is the correct measure.

Now I've gone back and assembled the complete "round trips" from the file (not hard to do), for persons who were driving a car, van, SUV, or pickup truck, added in the open-ended (e.g., vacation) trips, and weighted appropriately. So, this is as clean an estimated as I'll ever do.

My revised estimate, assuming 80% battery operation for 125% of the PHEV mile rating, yields the following estimated reductions in gasoline consumption from a PHEV addon.

PHEV pack size (miles), gasoline savings at US average round+open-ended one-way trip mix.
1 Mile 4%
5 16
9 26
10 28
15 36
20 43
25 48
30 52


In particular, the rumored 9-mile PHEV option from Toyota would reduce gas consumption by 26% (for the US average round + open-end trip distribution).

Let me complete the calculation: what would that save, over 100,000 miles, for a person getting 48 MPG now, at $3/gal for gas and $0.60 for the electricity to replace the gas. Survey says ... $1300.

Obviously, as the phrase goes, individual mileage may vary. This is calculated at the US average trip length distribution. A person with many short round trips would benefit far more. Persons with opportunity for mid-trip recharge (e.g., at work) might benefit more.

For a 30 mile PHEV modification, gasoline consumption would fall by just over half, at the US average trip length distribution, with no mid-trip recharge. The same 100,00 mile calculation as above would yield $2600 breakeven. I'd be willing to pay more because my (wife's) trips are much shorter than average. But that's the figure for the US average trip length distribution.

 

<div class='quotetop'>QUOTE(SomervillePrius @ Jul 26 2006, 01:40 AM) [snapback]292010[/snapback]</div>

If everybody drove such PHEV or BEV, you'll see lack of capacity.
There is a study by Dr. Robert Uhrig about PHEV...
http://www.tbp.org/pages/publications/BENT...s/Sp05Uhrig.pdf
On the sixth page, it states that you'll require 200 new 1000 MWe nuclear power plants.

Ken@Japan

 

With a plug-in option photovoltaic panels on the roof become even more attractive. They'd cut my useage during the day to compensate for the car charging at night.

I'm hoping to get a job closer to home in Fall 2007. When the new car comes out my round trip commute will be totally electric as it will be all residential and less than 9 miles total round trip. Stores are close too. So I'd love the option.

My parents are 10 miles away, and my sister is 30 miles, mostly freeway. mostly by freeway so still having an ICE will be nice.

 

<div class='quotetop'>QUOTE(ken1784 @ Jul 25 2006, 11:23 PM) [snapback]292380[/snapback]</div>

A 20 mile PHEV would require a 5 kWh charge every night. But the average US household uses 24 kWh per day. So, all a household needs to do is improve electrical efficiency around the house by 20% and this saving pays for the vehicle's electricity completely.

A user could replace all lamps with energy-saving bulbs, install AA-rated fridge and other appliances, insulate/ventilate properly etc.

Simply doing this would lead to no requirement for any more power plants to be built, and would supply the home-owner with 7,000 miles per year of "free" electric-motoring, saving $420 of gas in the process too.

 

<div class='quotetop'>QUOTE(clett @ Jul 26 2006, 05:44 PM) [snapback]292470[/snapback]</div>

Have you read the paper?
The study said 21.1kWh for 35 miles.

It doesn't work that way. You can't do averaging out your daily usage for the AC power.
At night, most people are sleeping, most lamps are OFF, fridge...TV set are also sleeping, so the elec power fee is cheap now.
But, the study is saying you'll need a certain amount of electric power at night.

Ken@Japan

 

<div class='quotetop'>QUOTE(ken1784 @ Jul 26 2006, 10:39 AM) [snapback]292546[/snapback]</div>

I have, parts of it are totally flawed! A good EV gets 200 Wh per mile, a Prius, as you have also said, can get about 250 Wh per mile. Lithium batteries are now 98% coulomb efficient (charge out vs charge in) - the author also totally underestimates this.

So 35 miles would not require 21 kWh, but more like 7-9 kWh. When this correction is applied to his arguement, only 150 GW would be required at night to charge up all of the nation's vehicles. This is just 18% of national electricity production, which would easily be covered by the night time - day time difference. So no new power-plants would be required.

Another issue that the author fails to mention is that the gasoline saved does not need to be refined. Not having these refineries running saves almost as much electricity per gallon of gasoline as it does to run an EV for the same amount of miles. Also, with a nation of plugged-in PHEVs, the buffering-capacity of the grid when V2G is taken into account is vast - so many "peak supply" power stations may not be required any more, leading to a reduction in power plants rather than a programme of expansion.

 

its my understanding that the amount of charge needed per mile is also dependent on the speed of the distance traveled. is this not true?

 

<div class='quotetop'>QUOTE(ken1784 @ Jul 26 2006, 10:39 AM) [snapback]292546[/snapback]</div>

ken1784,

Your cited article appears to be very good work, but I agree with others that the issue of the discrepancy of the results is largely due to the assumptions of what the typical vehicle would look like and how efficient it would be.

I did a parallel calculation starting from US annual gallons of gasoline, converted to Kcalories, assumed 20% of energy reached the wheels, and so on. By default, then, I assume the vehicle I model matches the fleet-average, roughly 20 MPG for the US. My calculations end up matching those in the article closely except for two items, which almost wholly explain the descrepancies.

First, as noted by others, the assumption about the net efficiency of the EV in this study appears somewhat low. Multiplying out the numbers in the study, the assumption is that an EV would have 61% efficiency. That is, total KWH/mile required to be input compared to KWH expended at the wheels. A good chunk of the is (15%) is attributed to the higher weight of the EV due to the batteries, which I would contend is surely an overstatement for a PHEV with a small battery pack.

By contrast, I ended up assuming 81% efficiency, due to combined transmission line losses (assumed 10%) and loss in running the EV (again assumed 10%), so that 81% of the power generated by the power plant arrives at the wheels (.9*.9). So, I'm working with the power the companies have to generate, not the power pulled out of the wall socket, but assuming a very efficient conversion of electricty to power in the EV.

I just picked some reasonable round numbers there. Evidence would convince me that my efficiency assumptions should be changed.

For what it's worth, I came up with 8.9 kwh for recharging a 20 mile battery pack, but this assumes net 81% efficiency and assumes the vehicle would look like the typical US car (i.e, mix of SUV and car) now. The same figure using the study's data would be 12.1 KWH (for 20 miles). That's a 27 percent discrepancy, wholly attributable to different efficiency assumptions (his .61 is 26% lower than my .81), to within rounding error. It seems completety reasonable that an assumption of even greater efficiency, and particularly, a smaller car, would get you down to the range of 5 KWH per 20 mile batter pack.

So, I think it's mostly about what vehicle you assume for the EV and its efficiency. I've assumed by default the US average, as has this study. On efficiency, I have no particular data to bear on that. Dr. Fusco cites a 20% loss for the Prius in the round trip of energy into and out of the battery (hence his suggestion not to seek out stealth mode if you want to optimize gas mileage), but my understanding is that newer battery technologies do better. So, by default, I guess I've assumed an electrical efficiency higher than the Prius, and a car much larger than the Prius, in my calculation.

The only other difference is that the study assumes that all cars would charge uniformly in an 8-hour period, to arrive at the 421 GWH peak power flow required to charge all the EVs in eight hours. From that, the study author cut the figure roughly in half to account for nightime slack in the power generating network. So, where my oiginal calculation figured on 114 GWH flow continuously 24/7/365, that would translate to 342 GWH flow required if compressed into 8/7/365. The discrepancy between the study number and my number, for total required additional flow of electricity needed (24%) is, within my tolerance for error, identical to the discrepancy in the assumed vehicle efficiency (27%).

If I arbitrarily applied the same reduction for nighttime slack to my estimate as the study author did to his, I'd get 163 new 1000MW power plants needed, compared to the author's 200.

Again, no concept of whether the nightime slack estimate is reasonable or not.

So, bottom line, I think just two items contribute to the disagreement: what size of vehicle are we talking about, and how efficient is it? But let's get real here. Given the unknowns, and given that total US electric capacity is something like 1000 GWH, we're more or less saying we'd need maybe a 15 to 20 percent expansion in capacity or equivalent improvement in efficiency if literally everybody drove an EV. That doesn't seem outrageous to me. Given that if this conversion takes place, the time period will be decades, accommodating that does not seem like a major stress.

Can I show that? Sure. A quick calculation from US DOE data shows that, 1999 to 2004 (last year available), electric power consumption in the US grew 1.3% per year. If the conversion of the US fleet to all-electric took 30 years, and raised electricity demand 15 percent, that would round to a 0.5% addition to the underlying annual rate of growth. That's a bit sloppy, but its about right. So, if there were no efficiency offsets, we'd have to step up capacity expansion to accommodate another half-percent growth above recent historical trend. Not trivial but not insurmountable either.

In fact, we've had growth rates like that in the recent past. If I looked at annualized growth rates in electricity generation for five year periods ending in any year from 1985 (limit of data) to 2002, they annualized rates of growth in power generation never dipped below 1.7%, and for by far the majority of the time were well in excess of two percent. So, not only could we handle the rate of growth required to accommodate the slow conversion of the fleet to electric, we've had higher-than-required rates of electric capacity expansion in the recent past.

So, my own belief is that if the conversion takes place slowly, capacity expansion is a non-issue. If done over, say, 30 years, that's about an additional 0.5% growth in electricity consumption, well within historical norms for rates of growth, compared to recent trend.

The only other thing I'd say is that I've heard people go on to talk about the cost burden of building that infrastructure, but that's where, as an economist, I draw the line. How will we pay for that? Who will pay for it? Same as now - you pay for it on your electric bill. The revenues from the 15 to 20% more electricty we will buy (assuming no efficiency improvements) will fund the expansion of capacity. Just as your current bill pays for the existing infracture. And bills in the past paid for our historical infracture.

 

<div class='quotetop'>QUOTE(ken1784 @ Jul 26 2006, 09:39 AM) [snapback]292546[/snapback]</div>

But it's not going to be that much more. And it can be compensated by less use during the day.

Awnold is going to pass his "Million Solar Roofs" initiative in California (I wouldn't be surprised if he's doing it right now, during the summer-long heat wave as a Global Warming thing). He wants to be re-elected. Even if he doesn't get it passed, his predecessor probably will. And those solar roofs are going to generate power during the day during peak useage. (All of the school roofs in San Diego will have solar soon, mine already does.) That takes some of the pressure off of the power plants during the day. They can take up the slack at night.

Toyota has already catered to the California market. The more California goes solar and wind, the more a plug-in and then totally EV car is going to be in demand. Toyota sells a lot of Prii in California. They've done it by giving the consumer what they want. No sense changing that policy now.

I really don't care what the Bozo in the White House wants.

 

<div class='quotetop'>QUOTE(clett @ Jul 26 2006, 12:08 PM) [snapback]292585[/snapback]</div>

Clett,

Excellent point, and one that I neglected as well. I just started from the chemical energy in the gasoline. If you don't need to make the gas, you don't need to consume the energy.

As you know, once you move upstream in the production process, the accounting for energy inputs becomes murky.

I mean, in fairness, if we'll have to generate more electricity to power the fleet than we do now, If I net out the energy cost of producing the gasoline, I must net in the energy required to (e.g.) mine the coal and extract the uranium used to generate the incremental electricity.

Ignoring the energy embodied in the capital costs, and refusing to take the argument one step further back than that in the production process, I'd say this is more a question of whether the energy saved by failing to produce the gallon of gas is offset by the energy required to produce the fuels for generating the additional kilowatt hours. All the costs get embodied in the prices of the fuels, so asking which approach is cheaper is a clean question. But asking about energy required for the entire production process is a tricky task.

I won't even speculate. If anyone has a good quantitive answer, I'd like to see it.

 

<div class='quotetop'>QUOTE(Godiva @ Jul 26 2006, 02:37 PM) [snapback]292685[/snapback]</div>

Governor Schwarzenegger's predecessor was removed from office in a recall election.

 

<div class='quotetop'>QUOTE(ken1784 @ Jul 26 2006, 10:39 AM) [snapback]292546[/snapback]</div>

Ken,

So, the key question(s) for the short-run answer to the issue of the required capacity expansion are:

1) How big is the existing daily peak-to-trough difference in electrical demand? In other words, right now, how bit is the nighttime "hole" that we could fill with EV demand before exeeding the daytime peak?
2) Secondarily, what fraction of that peak is being satisfied with higher-cost on-demand generating capacity?

If the peak-to-trough difference is large enough, and people are disiplined enough to charge at night, then it might be quite a while before any new capacity would need to be built.

Unfortunately, all I can seem to find is the occasional graph for some location, nothting even approaching systematic data on this. For the few pictures I have found, the daytime peak appears to be about twice the height of the nighttime trough, with a roughtly sine-wave shape to the curve. If: the curves are roughly symmetric, and total electrical demand for EVs boosts total overall electrical demand by 15%, but that demand had to be satisfied in an 8-hour period, then on any particular graph, the question is whether whether the trough height, plus 45% of the average height, exceeds the peak height. If not, then roughly speaking no additional capacity is required, if the EV load is neatly used to fill in the trough.

As I said, I can find no systematic data. For the couple of graphs I've found, yes, it appears that they satisfy that constraint - that trough + 45% of daily average < peak.

I'm sure it varies by location. But even if we agree that converting the US fleet to all EV would boost US electrical demand by (e.g.) 15%, it's possible that much of that could be accommodated by filling in the nighttime demand trough that exists now. Possibly more the the fraction assumed in the study you cited.

 

<div class='quotetop'>QUOTE(chogan @ Jul 27 2006, 07:51 AM) [snapback]292817[/snapback]</div>

I'm not interested in the micro numbers but macros.
My point is we need to think about the power distribution infrastructure.

I have no US peak data but TEPCO or Tokyo Electric Power COmpany's.
http://www.tepco.co.jp/en/utility/corp-com...ed/04i_full.pdf
On page#23(Page#30 of PDF), it says 47% least peak at 4AM-5AM.
Let's say 50% peak for 8 hours at night and 100% peak for 16 hours in daytime, which means 20% of Wh unit is consumed at night and 80% for daytime.

In the US, you consumed 4.038,000 Thousand MWh in 2005.
http://www.eia.doe.gov/cneaf/electricity/epm/table1_1.html
It was 11,056 GWh per day. Then, 2,211 GWh at night and 8,845 GWh in daytime consumed using the TEPCO number.
The 2,211 GWh in 8 hours at night means 276 GWe used in 2005.

The study says 424 GWe is required to charge all vehicles in the US.

I don't know. Anyway, it is huge if all of us goes to PHEV or BEV.

My point is "The idea is that PHEV will be charged during the night when demands are lower and there is a lot of spare capacity even in CA. " by SomervillePrius and "But the average US household uses 24 kWh per day. So, all a household needs to do is improve electrical efficiency around the house by 20% and this saving pays for the vehicle's electricity completely." by clett are not true.

Ken@Japan

 

<div class='quotetop'>QUOTE(ken1784 @ Jul 27 2006, 10:40 AM) [snapback]293154[/snapback]</div>

Ken,

First, point taken. I mistakenly compared the required amount of electricity to existing electrical generating capacity, not to actual annual electrical output. Let me redo.

Study says a steady flow of 424 GW is required, 8 hours a day, 365 days a year, in order to charge the fleet. I always have trouble keeping my units straight for electricity, by here GW x H = GWH, total amount of electricity required to charge the fleet = 8*365*424 = 1,238,080 GWH.

As you note, total current US electrical consumption = 4,038,000.0

So, I was wrong. The additional amount of electrical energy required, at that study's (perhaps somewhat pessimistic) assumptions, would be 31% of current total production. We'll need to consume 31% more electricity (not 15% as I implied before).

But, as noted, that's not the issue. The issue is how much additional capacity will be needed to meet that need.

And, duly noted, saving electricity at any other time other than the time at which the cars will charge is not relevant to this. Only efficiency savings during the nighttime charging period are relevant to the infrastructure question. The infrastructure question is a question of peak capacity. The electrical efficiency question is one of total cost .

At this point, now that I am on track, it is far simpler just to go back to two numbers: US peak capacity (1000 GWe, by my source) and the 8-hour-charging load per the study's (somewhat pessimistic) assumptions, or a flow of 424 GW for 8 hours (additional 424 GWe needed).

Abstract from the details. Americans definitely drive more in summer, and summer is also the peak electrical use for AC, so in fact, our consumption patterns may make this issue worse than you might imagine based on US annual averages. (In other words, both your cited study and my calculation worked from annual averages and did not consider that seasonal peaks in gasoline consumption also coincide with existing seasonal peak in electricity consumption.) Unless the daily peak-to-trough ratio is larger in summer (ie, if our air conditioners mostly idle at night.) I will look at this below.

Then, the question is, if the US summertime daily peak-to-trough were like Tokyo's (trough is about 50% of peak), could we add a steady 424 GW load at the trough and not exceed the peak? Clearly not, due to sine-wave shape of the curve, and the need to have charging cease by 8 AM or so. (Mor on these below too.)

Could we do it with a more sophisticated charging algorithm - instead of a flat rate for 8 hours, program the chargers for a higher rate at the bottom of the existing trough? After looking at a sine wave, looking at the actual Tokyo curve, and requiring that all charging be finished in time for the morning rush hour, my conclusion is no - even if we optimized the charge rates over the evening, we might not be able to do it under the existing capacity limit, due to the constraint to finish at 8 AM. But we'd be closer. Suggesting that a little sophistication in how the chargers are made to operate could help to clip the peak and would reduce total costs.

(An aside: I bought a Casio "atomic" watch last week. In the US it captures the Fort Collins time signal from a US atomic clock and resets to the correct time each night. It would not be beyond imagining to put that technology in the chargers, to allow management of the peak charging load as a function of the local time of day. End of aside.)

So, under the study's assumptions, yes, I agree that some capacity expansion would likely be needed if no other changes were made. And under those assumptions, the cited figure of 200 GWe plants does not seem unreasonable.

Four more thoughts.

First, capacity expansion would not occur at a steady rate. No doubt we'd ignore the problem for the first N years of EV growth, then have a crisis when nighttime charging load began to exceed capacity. In fact, economically speaking, that's probably the least-cost solution. We would not begin building capacity until the peak nighttime EV load began to stress the system. Looking at the curves, we could be half to two-thirds of the way through the conversion of the fleet before that happened. So the likely period of capacity expansion would be compressed, relative to the period of time required to convert the fleet.

Second, are there any soft-failure modes here? Do we have a shipwreck if we don't expand capacity fast enough?

I note that the seasonality of electrical demand (eg, prior page in Tokyo Electric report) strongly suggests that we could meet fleet charging needs, with existing capacity, for almost all of the year. That is, the daily trough in winter, plus EV charging load, would be well below the existing summer daily peak. So, as with air conditioner usage in California now, this would be a seasonal problem even with zero capacity expansion. The first sign of trouble would be summertime nighttime brownouts, as EV demand pressed on existing capacity. Then we'd all be surprised about it.

The clear soft-failure mode for PHEVs would be the old even-odd gas rationing plan that was used in the US in the 1970s, but applied to charging in summer months. E.g., each person would have to run as a straight hybrid (no night charge) for one day a week, based on terminal digit of license plate or something. Hugely difficult to enforce, of course. And, if we are talking a PHEV fleet, the problem is not as large as stated because some fraction of travel is still powered by gasoline).

Even so, with a mixed EV/PHEV fleet, you could just ask the PHEVs not to charge during peak periods. Again, tough to enforce, unless the Goverment regulated the chargers themselves so that they could be centrally contolled. (Not likely in the US.). Better to offer a cash incentive, pehaps, offset by some revenue source.

Third, a pessimistic thought and some new data. Your study and my analysis simply averaged demand over the year. Because the infrastrucure issue is about satisfying peak demand, that might be an oversight. We have modeled this, by default, on a world where everyone drives the same amount day after day.

How big an oversight is that. How large is the fluctuation in auto miles traveled, over the course of a year?

I turn to the National Household Travel Survey, do some calculation from the data, and arrive at the following conclusions about daily and seasonal fluctuation in US automobile (car, van, SUV, pickup truck) miles. One caveat -- I am not sure about the extent to which business travel is included in this survey. I'd have to do a bit of research to pin that down.

The results are about what I'd expect. On Friday, Americans drive 15% more than average. In August, they drive 9% more than average. I'm not sure the data have adequate precision to allow me to talk about Fridays in August, but the results are about what I'd expect: even accounting for the calendar (five Fridays in August 2001), a Friday in August is 20% above the average for August. Many people leave for vacation on a Friday in August. That's exactly what I'm planning to do this year.

Together, I'd suggest that single-day peak driving demand may actually be about 30% higher than the US average. On some Friday in August. And, August is almost certainly the existing peak demand for electricity as it stands.

Reluctantly, I conclude that analysis based on the annual average, without reference to intra-week and seasonal variation, signficantly understates the actual single-day peak demand that might reasonably be expected, and so understates required peak capacity requirements.

In other words, based on this information, the worst Friday night-Saturday morning EV charging load would be about 30% above the US average. And that peak occurs in August.

Four, an optimistic thought and some new data.

Does everybody have to charge their car up and done with it by 8 AM? No, not at all. Back to the NHTS data, pick off the first trip of the day, and in fact, only 42% of drivers have their first trip of the day start at 8 AM or earlier. And only 56% by 9 AM or earlier. (Average for all drivers all days). And on the critical Saturday AM shift (when we're finishing charging Friday night's big load), only 22% of drivers have started their first trip by 8 AM, only 36% by 9 AM, only 70% by 12 noon. (And that ignores people who did not drive at all on Saturday.) Ideally, I'd weight these figures by total miles driven during the day, but that would be a bit of work to construct.

So, the assumption that we must squeeze the charging load into an 8 hour period ending (say) 8 AM is wrong, and it is particularly wrong for the critical friday-saturday charging period. As long as people predictably slept later on Saturday (and were willing to program their charger accordingly), we could substantially spread the peak. So, you'd really have to do a micro-simulation to get any tighter handle on exactly how much additional capacity would be needed.

Sounds like the charger needs to have a function where the user can program it for "I'll need the car by xx hour tomorrow."

In summary.

Yes, you definitely have a point. I doubt I could pin it down any better than this. Some significant capacity expansion would be required for an all-EV fleet. It is possible that the required rate of capacity expansion, when it occurs, may be fairly fast, as the early years of EV conversion will require no capacity expansions. Weekly and monthly variation in driving patterns would probably make the peak load problem worse (ie, Fridays in August would be bad). But ability to stagger the start and stop times for charging would make it better, particulary the ability for most drivers to stop charging later on Saturday. So, quantifying the issue is complex at best. Some easy partial and stop-gap solutions may be evident. So, a "smart charger" could reduce peak Friday night load by finishing later on Saturday than on other days, and similarly for persons working at home (as I do), housewives, etc. "Smart" chargers could vary charge rate by local time of day to provide best fit to the existing variation in electrical demand. Restrictions on charging by the PHEV portion of the fleet could be used at peak periods (but would then have to be anticipated by gasoline suppliers).

Tough to quantify, but yes, I would say you definitely have a point. That's about as far as I can take it.

 

<div class='quotetop'>QUOTE(ken1784 @ Jul 27 2006, 10:40 AM) [snapback]293154[/snapback]</div>

Hi Ken, this study has got its figures TOTALLY wrong! Even some really obvious, basic stuff is wrong.

First, his assumption that 21 kWh is required for 35 mile range is wrong - it should be more like 7-9 kWh. This means that even in the highest possible demand scenario, only 150 GWe would be required to charge ALL PHEVs in the entire United States, simultaneously.

But of course this is also a wrong approximation. In making his calculation the author is assuming that every PHEV would plug-in to charge from empty to full every night of the year. It's not rocket science to notice that 35 miles times 365 days per year is 12,775 miles per year. Therefore, the author is assuming in his study that every single mile that everone travels is done by electric power. This is of course wrong, as with a PHEV-35, only ~60% of miles would likely be traveled under EV mode. So that cuts the 150 GWe again by 40% to just 90 GWe.

90 GWe is just 10.8% of national electricity production. This could EASILY be met with the existing grid infrastructure because less electricity is consumed at night by residences. To run an entire nation of PHEV-35s would not require any new power stations to be built.

This study is just wrong, wrong, wrong!!!!

 

OH BOY, A PLUG IN PRIUS!

It's beginning to look a lot like Christmas.

Dear Santa,
I've been a good boy this year for the most part. Here is my Christmas list.

Plug in Prius
Mini wind turbine for my home
solar roof for my Prius
solar hood for my Prius
aerodynamic flaring for the Prius for better MPG's

Thank you,

Oh, One more thing...Please give the big oil companies a lump of coal this year. They were very, very bad! :angry: