PHEV from Energy Point of View

As you can tell, it is not entirely straight-forward to calculate a savings per mile. For example, charging the pack overnight at off-peak rates greatly reduces the electricity cost.

From a purely monetary standpoint, an Enginer kit is probably not worth it.

But neither is a Prius. Better to buy a new Corolla.

But wait, if you buy new, you lose 25% of what you just paid, so buy used.

And so on.

About 10 years ago, I bought a beater Mazda 323 for my daily 120 mile round trip commute. It was a 4 speed manual -- basic transportation at its most basic. I put another 75,000 miles on it. The sole basis for operating the car was that it was the cheapest way to get to and from work, and all other factors, such as comfort, fun, style, were ignored completely. I was soooo happy to ditch that car for a Dodge Stratus, which at least had A/C.

When you discuss the economics of hybrids, EVs, and PHEVs, you have to include intangible utility. For an Enginer kit, the main utility is being able to show off 75 MPG (or more) on the MFD. Knowing that the energy is produced domestically increases that utility. Use solar power to charge your pack, and the utility increases further.

People spend thousands of dollars pimping out their cars. After-market ECU computers, superchargers, intercoolers, NOS, rims, suspension, paint jobs -- it's all about personalizing your car, trading cash to improve personal utility.

Intangible utility in a nutshell.

 

There is no question that from a cost viewpoint, most cars are a very expensive form of transportation. I really don't understand why anyone buys a brand new car.
I've paid cash for every car I've ever owned, and have owned dozens of them over the years, buy them used, drive them for a few years, sell them for not much less than I paid, and buy another different one. Have even sold many at a profit.

A used Geo Metro for $3,000 could get 75mpg if you drove it 30mph on level ground with a tailwind. There are people that get 55mpg with them after some very inexpensive tweaking. I've owned 3 of them, have one now. My Prius is a much nicer car. But it is in-fact a gasoline powered car that is just a little more efficient using an electric motor. It is not even CLOSE to being a Electric Car.

The Chinese Enginer kit looked pretty attractive at such a low price, until I started to find out the details. The biggest issue is that it requires the stock battery to be used and functional. These batteries are going bad in many cars now. A system which replaces the NiMH pack completely is a much better solution in my opinion, even if more expensive, it is worth the extra expense.
But I think the biggest issue is the very limited EVness of all these PHEV kits, particularly that you must spin the gas motor over 50mph, and the Prius gas motor must warm up the catalytic converter generating a lot of unneccesary pollution while it does. The GM Volt looks like a very good car. But at $40,000 (or more, be certain there will be shortages and wait lists by design) the cost savings in fuel is not a good reason to buy one.

 

Many people need to drive just 10-20 miles a day. I think the stats are 50% drive less than 40.
My commute is typically about 6 miles one-way.
We can recharge at work with "EV only" parking.
Thus with a "big enough" battery I could drive without using ANY gasoline when recharged at night everyday, if the car would operate that way, the PHEV's kit Prius won't do it.

My view is its about Co2 emissions and imported oil, not the cost at the pump.

 

You are forgetting about driveline inefficiencies with your 11 kWh of energy to the wheels. As you stated earlier this number is based on gasoline having 33 kWh of energy and a good ICE being 33% efficient. That does not equate to 11 kWh to the wheels only 11 kWh to the transmission.

 

You are not asking an energy question, but an opportunity cost question.

KISS: perhaps you pay 15 cents/kwh, but I think the national ranage is 6 - 20 with a median of around 12. Using 12 cents/ kwh, it costs 36 cents to travel ~ 11 miles EV, or 3.3 cents/mile. Petrol costs about 250 - 300 cents for 50 miles, or 5 - 6 cents/mile.

So, the engineer kit saves about 2.5 cents/mile. If it and the car are good for 150k miles savings are $3750 before time cost of money is factored into the calculations. Grossly, the out of pocket upfront costs about balance the savings, which is very complimentary to the EV system, since it means that an environmental choice does not cost you extra money. Well, assuming that you view EV as a smart move for the environment.

 

This thread, Cost Calculators, identifies some web-based operating cost
calculators that may help get a handle on all-electric vs. hybrid vs. ICE-
only costs in individual-specific situations.

Tip o' the hat to member Rybold :yo: for the finds.

 

I would question the 80% electric motor efficiency assumption. I think it is much higher. What I have found, with a Hymotion kit, is that you can go about 4.5 miles for every kWh in the kit, which works out to about 20 miles for the about 4.4 kWh the kit uses. I haven't been able to check with a meter, but I think you do lose about 10% for recharging, so that works back out to about 5 kWh for 20 miles, or 4 miles for every kWh pulled from the grid, which would mean the Enginer range is really 4.5*4.0 = 18 miles, which means the calculations from that point on are too low by about 70%. Also, as has already been pointed out, costs for electricity vary greatly, as does the "cleanliness" of the method of electricity production.

Also, one thing that everybody seems to completely overlook, and which was pointed out by FL_Prius_Driver, is that you're doubling the life of the car because you're not running the engine. Also, now you're not needing to change the oil as often either, since the engine is now running only half the time, or even less depending on the circumstances.

So in my opinion until these factors are also counted, you're not getting a complete picture of the savings. I did the spreadsheet calculations at http://priuschat.com/forums/toyota-prius-phv-plug-in/83135-anticipated-price-2012-phv-prius-8.html , which also showed that the future price of gasoline was the most important factor in the calculations, and of course at this point nobody knows what it will be in 10 years. But I'm willing to bet that it will be higher than it is now, and in fact as the price of gasoline rises, the resale value of any kits will also rise, which is another cost-savings potential that isn't able to be calculated at the moment.

 

I manage to drive 2.8 miles (each way) to work and back, entirely in EV mode, using side streets and going under 34MPH. (Unless I step on the gas too hard.)

You may say that if it's only 2.8 miles to work, an environmentally better solution would be to ride my bike, but I know how people drive on these roads and I value my life and limb!

 

Hi sub3mar...,

While the Prius motor is better than 80 % efficient, the pack to wheels efficiency during EV level accelleration is not. This is because the Prius is a hybrid car, and not built for the large current demands of EV operation.

There was an old thread where we disected Atilla's braking efficiency measurements, which included accelleration back up to speed.

Accelleration efficiency could be dramatically improved if the accelleration was much slower, the pack had much less resistance (read this EV Sized) and the inverter hand bigger transistors....

 

LOL, your post title is "from an energy point of view" but your discussion is "from an economic point of view". No secret that this is still an expensive hobby. However, if you want to improve the economics, charge your pack at night when electricity costs significantly less !

 

And when you're paying $7 a gallon you save $1.54 in gas, and when you're also paying $0.15/kwh for your wind and solar generated power your savings are significant.

For my calculations, i should save about £1.40 a day in fuel. i end up driving 7 days a week, so payback will be about four years, if the kit lasts that long, or less of fuel goes up more (which it will)

 

Just read: A sixth bicyclist is killed in Tampa in a collision involving th and you'll agree. I think at least two of the six people killed around Tampa in the past couple of months used a bicycle to commute. At 2.8 miles though, I would consider running/walking there. At least if you're on the sidewalk it is tougher for the cars to run you over.

 

May not be economically justifyable yet...but certainly feels good to generate more power than I need (solar & wind) and plug in my 12KWh PHEV Prius each evening.

Scott
www.smilingdogsranch.com/priusblog

 

Walking on the sidewalk would not have saved you from this crash. The bicycling victim, Diane Vega, was standing on the sidewalk waiting for a the crosswalk light, when a right light runner caused a crash that did not stay on the roadway.

This is same way Kathy Cook was killed on my bicycle commute route. She commuted by transit bus, not bicycle. She, and the six others injured in this crash, had just stepped of the bus and were waiting for the crosswalk light. I didn't know her, but a fellow cyclist worked with her for many years.

The bike route is now protected from the roadway at this intersection. Pedestrians are still at some risk.