The Money Part of Plug in Technology...

Great references, thank you
Only one issue though in your comparison.
You are comparing the CO2 produced at your car by one fuel type vs the CO2 produced by generating the other fuel.
To get a true comparison you should take into account the CO2 cost of refining and transporting the gasoline (not the drilling though as then you would need to add the CO2 cost of drilling/mining the fuel for the electrical generation).

Your point that plug in technology isn't a panacea is good though. While it is definately an improvement it isn't the perfect solution.

 

This is a fair point, but I think it only changes the numbers modestly. From what I've read, the total energy overhead for oil ("well to tank") is about 15% of the energy value of the gasoline. For coal, the number that is quoted most often is 80:1 energy return-on-investment, which would be just over 1% overhead for coal. For nuclear, there are no good studies, but something like E ROI of 3-to-1 would be plausible.

So, for Virginia Power's generating mix (from coal, nuclear, natural gas and other sources, in order of importance), adding in the energy overheads might change the numbers modestly. But not much, I think, and the unknown EROI for nuclear makes the calculation too uncertain to be useful.

What has me more worried at the moment is the data above. Up to now, everything I've read has shown 4 miles per KWH. But looking at the zero- and low-gas-use days above, that's a pretty consistent 3 miles per KWH. At 3 mi/KWH I wouldn't be saving any carbon at all.

So I either need to put a meter into the circuit to see what I'm actually getting on mine, or I need to go for rooftop photovoltaic.

My original plan was to feed the battery with purchased clean electricity, but that fell apart this year. I can't buy clean electricity any more.

And now for a rant. As an economist, it annoys me that my only choice for clean electricity is to manufacture it myself, on my rooftop. That's expensive, inefficient, and means I'd have yet another system to maintain. It's an archaic "cottage industry" model of production. I want somebody to produce clean electricity professionally, on a large scale, and just sell it to me. I'd be happy to buy it. But here I am, money in hand, and no way to buy clean electricity. It's an amazingly stupid situation. But stupid is as stupid does, or something. If that's my only choice, I guess I need to get more serious about rooftop solar.

 

Please keep in mind that my data is from MY commute which includes going up and down a big, long hill. Presumably, the high rate of energy use on the way up should be made up for by the extra regen energy I get on the way down.

In practice, it may not be that simple. Driving up and down hills may be significantly less efficient, if only because of the slow speeds on the way up (to stay in EV mode).

One of these days, I'll get around to doing an experiment to determine my miles/kWh on relativley flat ground, but I haven't done that yet.

On my regular commute up and down the hill, I seem to be getting between 3.1 and 3.3 miles/kWh.

Arthur

 

OUCH.

I'm going to completely disagree there. Not least because I'm a girl...

Anyway. My conversion cost me £2,000 - a lot less than a hymotion kit. Secondly, I buy all of my electricity from a green supplier. And while I can't guaranty that every electron I use comes from a renewable source I know that an equivalent amount of energy to the amount I use is put into the grid on my behalf from wind, solar etc.

For all of that, I'm generally finding my gas lasts twice as long in our DIY PHEV prius than it does in our regular Prius. Think 800+ miles a tank rather than 480 miles a tank.

I'm not doing it to save money. I'm doing it to help move battery technology on and encourage others to get an EV or PHEV.

It also lets me be lazy and get priority parking in the local malls and park and charge in over 200 locations in the UK.



Nikki.

 

That makes sense. I don't think the Hymotion battery accepts any recharge at all while driving, so the regen can't refill what was spent getting up the hill.

Fact-checked that. Yes, Argonne national labs said that in their evaluation -- only the NiMH battery accepts regen.

http://www.transportation.anl.gov/pdfs/B/502.pdf

 

While you are doing the solar panels, look into solar water heating too. On another thread regarding solar panels, it was discussed that solar water heating gets "the most bang for the buck" as far as reducing electrical use (or gas use) vs cost. You'll get a nice tax credit for it as well, and it is less expensive than a PV system. But, if you are feeling your oats, do both.

Don't forget that ensuring you have adequate attic insulation is a very inexpensive way to reduce electric/gas cooling and heating costs as well.

 

I had figured out a way to capture ALL of the regen on the way down the hill. Now, with the CARB update, I am no longer able to do that. It's a long story.

Since the NiMH battery is the only one that accepts regen, I had to run that battery's SOC down to about 45% before starting down the hill. I was able to do that by putting the car in EV mode with the Hymotion system turned off. I would drive this way on a flat stretch (draining the NiMH battery down to 45%), and then start going down the hill. I would stop halfway down the hill, power the car off, turn the Hymotion switch on, and power the car back on. That routine would allow me to capture all of the regen AND stay in EV mode.

As I said, the CARB update complicates things, making it impossible to get the car into EV mode when the Hymotion system is off. They either have to change their software or I have to install a manual EV mode switch.

But, it should be possible to capture as much regen as the NiMH battery can hold. You can take the NiMH battery's SOC from 45% to 75% without ever being kicked out of EV mode. That's quite a bit of regen (my whole hill).

So, my mi/kWh is probably low because of the inefficiency associated with driving at 10-20 mph on the way up the hill. It's not because I'm losing regen. On all of my tests, I have been able to capture all of the regen on the way down the hill. Of course, there IS some additional inefficiency associated with putting out energy to get up the hill and then getting it back as regen on the way down. You don't get it all back.

On a separate note, I was using my Kill-A-Watt meter to time my charging today. I checked it every 10 minutes and found that it was consistently taking 10 min to add 0.20 kWh to the battery. That's 1.20 kWh per hour or about 4 hours to charge the whole battery. I think the charging rate slows down as it gets close to full but MOST of the charging is completed in a little under 4 hours.

Arthur

 

Wow CARB seem to have screwed that one up. Anyone getting deja vu?

What is it exactly about regen into the auxiliary pack that CARB doesn't like?

It almost sounds as if Hymotion have had to cripple their system in an update. It's a bit like buying a computer but then having the operating system turn off all except one processor...

I'm glad suddenly that 1) I don't live in CA and 2) I have a DIY which could regen a whole phev battery pack if I had a hill big enough..

 

Actually, the CARB update just forces a 1-minute engine warm-up when you first start the car. This doesn't really have anything to do with regen. In fact, there is a way to prevent to warm-up, if you want to.

The connection with regen is that I used to be able to use the Hymotion system as nothing more than an EV mode switch. That allowed me to run the Prius traction battery down to 45% which, in turn, allowed me to get all of the regen from going down the hill. With the CARB-mandated engine warm-up, there is no way to get EV mode on when the Hymotion system is off. So, I can only get about 2/3 of the regen from going down my hill. ...unless I decide to install a separate EV mode switch.

Sorry for the confusion, but it's a complicated thing to try to explain.

Yes, it would be nice if the Hymotion system could also accept regen. However, Hymotion designed their system to be as simple as possible by making it almost completely separate from the Prius system. When they install a Hymotion system, there are virtually no changes made to the original Prius system. The Hymotion system simply piggy-backs on the Prius and feeds energy into the traction battery when the Prius isn't looking.

It's actually a very elegant design and it avoids a lot of problems and a lot of extra costs.

Arthur

 

I love how people always figure out pay back (on technology that actually has a pay back) and then complain about it. People don't do this for other mods on their vehicles, like a stereo or horsepower parts.

What you ought to be saying is that a plug in mod will get you great gas mileage and savings right now. Does every purchase have to be about when the break even point is?

 

so OP...question here...

how long will it take you to pay back the cost of your "non plugged in" car?

and exactly what formula would you be using to calculate that payback?

i have thought of this and lets see... a monthly bus pass would cost me nothing since my employer would gladly provide that to me free of charge (which would be nice except that my hours start too early for bus to get me there)

speaking of employers, mine allows me to plug in at work. now granted, i dont really use a lot of their power and i have often toyed with the idea of maybe doing some extra errands in the morning or during lunch to create a higher demand for electrons.

better yet, if i had and EV that say, got 100 miles per charge. i would just plug in at work only. not plug in at home at all unless i had to.

so you see, a specific answer to your question is really only one you can provide. determining the real cost of your decision would be extremely difficult really. around here, for example, about 60% of my power is hydro, then another 8% is wind, solar, etc.

but that is because we use coal for peak demand power. now, i am usually at work and despite what i said above, i do more than 2/3rd of my charging at home (my estimated benefit from plugging in at work is about 5-7 KWH a week since i work 4 - 10's) but around here, 100% of our off peak demand power is hydro (we sell as much as is legally and financially-wise as possible during off peak times...better than having a dam overflow!!)

so your carbon footprint could be greatly reduced. but lets get away from individual numbers here and look at possibilities.

the more EV's plug in's etc that people buy, the more that will be available and the more opportunities companies like BP, etc will have to thrive. that can only benefit us.

what is the true price of not having to buy a barrel of oil from a foreign country?? what is the true benefit of being able to concentrate our carbon footprint at a power plant instead of 100 million exhaust pipes? what is the true payback and what scale should that payback be based on??? 2009 gas prices? or maybe 2008 if you are in a hurry?

then again, maybe we are asking the wrong questions here

 

At $4 gallon it has to save 2500 gallons-lotta gas. If you assume a "normal " prius gets 50 mpg and the Hymotion will get 100 mpg, the Normal Prius has to use 5000 gallons or 250,000 miles-and that is $4 gas, not $2.50 gas. Now at 8 gallons the numbers become plausible-saving just 1250 gallons and 125,000 miles.

Great idea, but..... It also shows the problem with Toyota spending another $5000 for an extended plug in range Prius--just 1/2 all the numbers. 125,000 miles at $4 gallon.

Charlie

 

Re: Tax credit for converting

I'm pretty sure that you only get the credit you site for a 'NEW, qualified plug in electric drive vehicle' (from BKD,LLP site) For a conversion the max credit is 10% of the cost of the conversion not to exceed $4000. I am looking for an IRS interpretation on this if anyone has the link. To qualify for the full $7500 plug in credit the vehicle must be made by "'manufacturer' as defined in title II of the Clean Air Act. Not sure if Hymotion or other after market converters meet that standard. (bkd.com)

 

You're missing the state tax credit which is $1.50-$2.00/ CEC-AC watt depending on your utility. That should translate into another $5000 of credits or so, basically cutting the cost of the system in half.

If you're looking for the smallest "break even" point, reduce the size of the system so that it doesn't offset much more than your "peak" or "excessive" power usage. It should decrease your "break even" point by another couple years.

If you're paying $140/mo, I'd look for a ~3 kW DC system. Looks like your quoted system is around 3.5 kW DC - enough to offset probably 75-80% of your electricity, but probably only about 50% of your electricity use falls into the "excessive, high dollar" category.

Yes, the up-front cost is fairly large - but what else can you buy that actually has "break-even" point? And then continue to save you money at least another 15-20 years past that?

That shiny Prius you're driving doesn't ever break even - only when comparing it to other gas guzzlers.