The Experiences of Two Plug-In Hybrid Early Drivers

We spent two very rewarding days at the Air Resources Board’s Zero Emission Vehicle Technology Review in Sacramento September 26-27. A few days ago, I described the background for this event at background for this event. I delivered a shorter version of this text as accompanying commentary for our eight-slide-presentation, which you can see at Presentations or at CalCars. We had been hoping that all the illuminating presentations would be available by now, but that hasn’t happened. When they are available, we will post additional comments at CalCars-News.

The Experiences of Two PHEV Early Drivers.
By Felix Kramer, Founder, CalCars

I tip my hat to Toyota, EnergyCS, SMUD, Andy Frank, and the plug-in advocates who never give up.

In Sept 2004, I came to the ARB hearing on the implementation of the Pavley Bill. In my testimony I said "the elephant in the room" is PHEVs, which could start saving CO2 emissions faster than any other vehicle type. Several commissioners looked at each other, talked, and agreed it was necessary to re-visit PHEVs. I’m glad that’s happening now.

My testimony reflects my experience as the world’s first non-engineer consumer owner of a PHEV and that of my colleague Ron Gremban, an engineer and CalCars’ Tech Lead, Ron is the owner/driver of the world’s first PHEV Prius.
In the fall of 2004, Ron Gremban led a team that for the first time converted a hybrid production car (his 2004 Prius) into a PHEV. He has since driven his lead-acid PHEV 17,000 miles, charging mostly at his solar-panel-outfitted home. Then on April 7, 2006, I took delivery from EnergyCS of a lithium-ion conversion of my 2004 Prius. I have since driven 8,000 miles. Both cars are parked outside.
Many of the issues I address may be generalized to provide insight into the impact of PHEVs as they begin to penetrate the population of car drivers. I’ll start with performance notes, followed by anecdotal reports and issues.

How things have changed! I used to dread a day filled with short trips. Even on the low-emissions Prius, each time I’d have another engine warm-up and much-reduced MPG. Now I love those local errands — they’re mostly all-electric. In my first two days, I drove 130.71 miles on 1.102 gallons of gasoline. That’s 118 MPG. These numbers included an airport run with about 40 miles of 65 MPH highway driving.
Early on, I made a round-trip from the Peninsula to downtown San Francisco. I went beyond the mixed-speed range of the PHEV Prius: 64 miles, including about 55 at highways speeds (North on flat Rte. 101, back on hilly I-280). Bottom line: 81.4 MPG. That trip included 98 Watt-hours/mile or 6.2 kWhr out of the battery.
The slide shows a representative driving day with the "boosted" full or partial electric range: 50.8 miles of mixed-speed driving, at an average of 124.1 MPG plus 123 Wh/mile. The numbers speak for themselves.
We always try to say "100+ MPG (plus the cost of electricity)." What does that work out to added up? The answer is 76-83 MPG equivalent, depending on assumptions (Sacramento Municipal Utility District or Pacific Gas & Electric power rates, and $2.75 or $3/gallon for the cost of gasoline).
These numbers demonstrate that 100+ MPG is possible with an after-market conversion that suffers from severe limitations of any conversion, including forced gasoline use above 34 MPH. An optimized, from-the-ground-up PHEV from Toyota and other OEMs could do much better!

As PHEV owners, plugging in is "optional," since we know we can reach our destinations with gasoline. Our reasons to plug in have evolved:
1. Saving money.
2. Reducing CO2 and other emissions.
3. Reducing use of imported fuels (doing our bit for energy independence)
4. The pleasure of driving silently on local streets at low-speeds, which accounts for more than half of our everyday driving. (Ron’s favorite)
5. The desire to avoid the generally negative experience of going to a gas station.
6. The intangible "gadget/techie/boasting" factor of being able to maintain high cumulative MPGs on a real-time display, and to achieve extended intervals between fueling by using more electricity.
While the final point may appear to be frivolous, it’s a real — and generally highly positive — behavioral factor. It’s the same dynamic at work among many Prius drivers who report that their ever-present "driving companion" (a feedback screen showing current and cumulative MPG) has affected them. It’s why you hear many Prius drivers say they’ve changed to become safer, slower, cruise-control drivers. It’s why you see many hybrid owners driving at or below the posted maximum speed on highways — they’ve adjusted their driving behavior to the message that each additional mile over 55 MPH causes an aerodynamic hit of about 1 MPG. (In fact, if every new car came with a real-time MPG indicator, that could probably accomplish a 10-15% reduction in total vehicle fuel use faster than anything except getting people to keep their tires inflated!)

Convenience is barely a factor. For home charging, it takes approximately 9 seconds to plug in when leaving the car, less than 9 seconds to unplug on the way out. When I’m traveling, I’m generally willing to explore the availability a 120-volt outlet in a hotel parking lot — and I carry a 100 foot extension cord. And of course, the "dongle" — when we brought my car to Washington, I showed that and said, "I’ve brought my infrastructure with me," which got a big laugh.
Price signals are the main factor (with my PG&E E-7 whole-house time-of-use meter).
Compared to this 7.6 cents, when the alternative is a 50 mile/gallon battery-sustaining Prius, gasoline wins on cost against on-peak charging until it reaches $3.80/gallon. Yet even at current $2.75-$3.25/gallon, I occasionally charge on-peak anyway. Why? Remember the last slide? For reasons 2-6.
To the extent this "opportunistic charging" becomes a problem as more drivers plug in, it can be addressed with additional price signals, such as that included in the PG&E "Smart Meter" plan the CPUC recently approved, which includes both an additional off-peak discount and a "Critical Peak Pricing Plan" with a 60 cent/kWh surcharge on hot summer days.

The combination of solar electricity and PHEVs is a huge carbon-killer. In mid-September, I got a SunPower home rooftop photovoltaic installation. Initially, mine will be like the typical on-grid system: returning power to the grid in the day, recharging the car mostly during off-peak, night-time hours.
But in the power-outage and earthquake-prone SF Bay Area, people are highly interested when I explain that my system will later be uniquely configured for what I call "Vehicle-To-Home" (which provides a preview of to bi-directional Vehicle-to-Grid future). In extended power outages I will be able to manually disconnect/island the PV system from the grid and re-route the system’s output. When the sun is shining, PV will power a small part of the house (one line, with refrigerator and lights) and charge the car. When PV power is unavailable, the car’s batteries will power that line.
ring an extended power outage and cloudy days, once the battery is depleted, the engine of the car (parked outside) can act as an emergency power generator with far lower emissions than the external generators available for these purposes. (Such emergency generators must be run every few weeks even when not needed, so they are maintenance headaches, and their fuel supplies are potential safety hazards.)

this doesn’t belong strictly in a technical session. Suffice it to say that there’s a growing interest and awareness, and many indications of specific support for PHEV commercialization. You can keep track of all this, and the continuing media attention, by joining the 4,000 subscribers to CalCars-News.
At, you can also see:
The evolving views of car-makers;
High-level endorsements;
The growing coalition supporting PHEVs.

From 2001-2004, the main question I got was "What’s a plug-in hybrid?" In 2005, that first question became, "Good idea, but how are you going to prove anyone wants them or will pay more?" In 2006, the question, at the growing number of public events promoting PHEVs, and every three weeks or so when I refuel, became, "How/when can I get one?" And going forward, we’re expecting to be involved in activities that will help catalyze far more rapid adoption of this technology, with evolution of the range extender fuel as well.

Thank you for your attention!

Felix is an entrepreneur with a life-long green streak. He enjoys communicating his enthusiasm about what is new, unique, and significant. He is the founder of, The California Cars Initiative, and has been promoting 100+ MPG plug-in hybrids full-time since 2001. He posts his own selection of significant developments for PHEVs at the CalCars News Archive. His first entry at Hybrid Cars, Car Owners Strap into the Drivers Seat, in August 2005, expressed his view that the industrial world is in the midst of a major change — hopefully, it is not too late!

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  • schiappas

    PHEVs look like a good idea unless that is you have PG&E for your utility. With top tier rates just raised to .37/kw it just doesn’t make economic sense.

  • rafael_g_seidl

    Felix –

    nice summary, thank you. What strikes me is the narrow focus on fuel economy and the energy cost per mile driven.

    It would be helpful to also include information about the premium consumers should be prepared to pay for a series production PHEV with similar performance characteristics. IMHO, the ROI horizon for that premium should be on the order of 10 years, since there are fringe benefits (points 4 and 6).

    You indicate that the purely monetary energy cost of your PHEV’s gasoline plus off-peak grid electricity is comparable to traditional fuel economy of around 80 mpg (point 3). If we compare that to a ICE-only vehicle that gets e.g. 25 mpg combined, the annual difference at 12000 miles/year would be 330 gallons of gasoline, worth around $1,000 in CA (assuming average gas prices will be about $3 going forward).

    Future inflation reduces the NPV of future savings, but also increases their amount, so this cancels out. Ergo, an up-front premium of around $10,000 should be acceptable for a 10-year ROI horizon, assuming that lifetime maintenance costs will not be significantly higher for a PHEV.

    However, this sum would have to cover the PHEV battery pack, power converter, electric motor, drivetrain control enhancements and installation cost. It does not include the monetary and psychological value of your contributions to GHG mitigation and energy independence.

    Is it feasible to produce a PHEV variant of a regular ICE-only vehicle and sell it at a premium of just $10,000? The mfg cost premium would have to be substantially lower to allow for sales & marketing overheads.

  • ray.whalley2

    Great stuff Felix, its amazing how critics of this solution always miss out on the oil supply and eco issues when demonstrating the financial justifiction.
    I am paying almost £1 sterling per litre for unleaded petrol in th UK, I think the sums work work using these figures.
    Still no sign of obtaining the PHEV conversion anywhere in Europe yet, although Amberjack projects in Grantham keep promising!
    I like the bit about powering the fridge with the Prius.

  • rafael_g_seidl

    Ray –

    I did not “miss out on the oil supply and eco issues”, I simply do not have any data regarding how much these are worth to prospective customers. Given the fiasco in Iraq, that number may well be higher now than it used to be, but I suspect it will still be close to zero for *most* consumers as long as the majority gets a free ride on these issues. Raising US gasoline and diesel taxes would make PHEVs attractive even at much higher up-front premiums.

  • rafael_g_seidl

    William –

    your (large) PV array could indeed produce electricity during the day that could be traded against night-time hydropower from the grid. You’d need a high-quality power converter to feed juice into the grid, though. The alternative is a bank of (lead acid) batteries to buffer the energy; deep discharges would severely shorten its lifespan.

    Either way, you really could be driving on pure sunshine at zero recurring energy cost. However, you’d still have to amortize its initial cost and incur cleaning overheads plus insurance fees or repair costs (e.g. after a hailstorm).

    Btw, the combined cost of Iraq, Afghanistan and homeland security has been over $300 billion so far. A huge number, to be sure, but the US population is around 300 million. Ergo, you’re off by a factor 10.

  • hybridcars-jadon

    Give up the “fuzzy math” of MPG after plugging-in. It is better to account for your mileage as a combination both gallons of gas burned and kW-hr of electricity used. For each trip, log all three values (miles, gallons, and kW-hrs). Many consumers will only want to hear the miles per dollar, so, if you have to summarize down to one number, consider using that (MP$). If you want a number that is more eco-conscience, try miles per cubic-foot-of-CO2. Just stop saying 100+ MPG, because the people that aren’t listening today will certainly ignore you when they feel that you aren’t counting the costs of the electricity.

  • gojoe283

    I only wish the plug in option was available for the 2001-2003 Prius. This model didn”t get as good mileage as the newer model, and I’d be willing to forgo stuff like A/C (never use it anyway) to get the higher mileage. The requirement to run the gas engine till it warms up, causes fuel mileage to go way down when on short trips…Bill H.

  • Chuck S.

    I assume the Honda Civic Hybrid is not a possible PHEV because it cannot run on electric only. True?

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