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Renewable Energy Access
March 3, 2006

Plug-In Hybrids: The New Focus for the Future of Transportation
New approach, available today, allows renewables to address
transportation needs

by Prof. Andrew Alfonso Frank, Univ. of Ca.-Davis

Recently there has been a lot of interest in the concept of the
Plug-In Hybrid Vehicle or PHEV. I have been researching this concept
for about 30 years. Over this time, there have been major
improvements in the basic components, such as the batteries, the
Continuously Variable Transmission or CVT, and computer control
technology in vehicles. As a result, the technology is now ready for
introduction to the mass market by the major car companies. We expect
that the public will begin to demand this type of vehicle now because
they have finally realized that the Hydrogen Economy won't happen in
less than 30 to 50 years -- if at all. The reason is that there is no
infrastructure for the efficient creation of hydrogen and the
transport of hydrogen will be a problem forever.

In contrast, the Plug-In Hybrid can use as much as 90% of their
driving energy from electricity using the currently available
electric sources already in our society, ie the standard outdoor
plugs at 120 volts and 1.5 KW in the US and 220 volts at 2 KW in much
of the rest of the world. The rest of the energy for these
automobiles can come from liquid fuels such as gasoline, Diesel or
ethanol from biomass. In addition, the vehicles can be charged
directly from small wind and solar systems on top of our homes and
workplaces. Of course, large wind and Solar systems could also be
used much more effectively. Since wind and solar generators are
intermittent, they need an energy storage mechanism to be effective.
The batteries of the PHEV's can provide this storage capability at no
cost to the Utility companies.

The reason the PHEV is so attractive now is that at the current cost
of gasoline is $2.50 and rising whereas the average cost of
electricity is stable at about 8 cents/kWh. This translates to about
the equivalent of 75 cents a gallon of gasoline when used in a PHEV.
In addition, in most places in the US, outdoor plugs are available
everywhere in our society. Thus, in contrast, to the much touted
hydrogen economy, there is no need for massive infrastructure
development and construction. The PHEV allows us to immediately
transition from our dependence on oil for transportation to one where
we can begin to transition to cleaner and more efficient electricity
without a need for new infrastructure.

A major difference between the PHEV and the Electric Cars of the past
is that the PHEV does not have to be charged since the car is
designed to operate the same whether the batteries are fully charged
or at its maintenance state of charge, SOC, about 20% to 30%. With
this reserve SOC the batteries are always available for extra power
when needed. In addition, most cars in the US and the world are used
about 3 to 4 hours a day, meaning it is parked somewhere for 20 to 21
hours a day. Thus the PHEV can be plugged in somewhere to charge its
batteries most of the day. We have constructed vehicles that use
about 200 to 300 watt-hrs /mile. Thus a 60-mile range requires 12 to
18 kWh. Or at 1.5 kW from the 120 volt plug 9 to 12 hours is required
to achieve 60 miles of range for a small car to a full size SUV.

In terms of practical applications to our vehicles, we have designed
and constructed at UC Davis eight vehicles in the last 15 years that
show that the concept applies equally to small cars up to full size
SUVs that do everything a conventional vehicle does in the US
including towing trailers while running mostly on electricity from
the wall plug or from wind or solar systems. In fact, we have shown
that a 60 mile All Electric Range PHEV full size SUV generates less
than one half the CO2 emissions of a compact car and uses less than
one quarter the liquid fuel of a compact sedan. In addition, these
PHEV's have one quarter or less of the moving parts and weigh no more
than the conventional car because they have much smaller engines
(about one third the conventional) and much simpler and lighter
transmissions. This technology can be transferred to industry for
high volume manufacturing now.

The reality today is that the car companies have been focused on
ever-larger trucks and vehicles that get lower and lower fuel economy
but do meet stricter emission standards. They are however emitting
more CO2. The PHEV can reverse these trends since the vehicles that
we have constructed show not only zero emission operation on a daily
basis but when using gasoline only, the fuel economy is more than
double the conventional car. If a vehicle travels 40 miles a day
commuting to and from work and the vehicle travels 15,000 miles a
year the effective gasoline mileage for a PHEV is over 250 miles a
gallon. Or compared to conventional car, the PHEV will use about
1/10th the liquid fuel. This fact makes bio-fuels such as ethanol
from cellulostic materials and biodiesel practical since we can
supply 1/10th of our current oil energy use from croplands and waste
agricultural products. In addition, as batteries improve, the
electric range of the PHEV can increase reducing the need for liquid
fuel further.

Finally, the bigger battery packs of the PHEV can be used to power
the house or provide relief for the need for peak power in the middle
of the day. The key to this direction of energy flow from the vehicle
back to the grid or V2G is to do it at a low power level so that the
efficiency of energy transfer is high. Then to affect the overall
grid, we would use more vehicles, ie if there is a need for 1MW of
electricity at a certain time, it could be supplied by 1000 vehicles
at one KW or by 100 vehicles at 10 KW. We are saying that 1000
vehicles is the choice because of efficiency and infrastructure cost.

Conclusions:

The PHEV concept is now ready for development by the major car
companies, since all the necessary technology is available. A few of
these technologies need further development to bring the cost and
durability to a level demanded by the car companies and the consuming
public. These requirements mean that the batteries, the CVT, and all
the powertrain components must be maintenance free and warranted for
15 years and 150,000 miles, and they must be within the range of the
cost of a conventional vehicle of today while providing a profit to
the car companies and their suppliers. In addition the public must be
educated to demand that these vehicles be built to reduce the risk to
the car companies for their investment in the PHEV concept.

It would appear that the low cost of electric energy (1/3 to 1/4)
compared to liquid fuels, the fact that the electric drive technology
can provide even greater performance than conventional gasoline
engines, the fact that big battery pack can begin the integration of
the transportation and the stationary energy sector, and the
availability of home fueling would be enough incentive to attract the
current price difference. However, a car company needs to be assured
that they will be able to recover their initial investment in the
technology and ultimately make a profit in a short term.

The best way to do this is to make the information about the benefits
of the PHEV available to the public and to have the public demand be
voiced in "soft orders" which basically says "build them, we will buy
them!!" to the car companies. The effort by Austin Energy, EPRI,
CalCars various magazines and newspapers is beginning to get the
message about PHEV's out. Our US president recently mentioned
biofuels and the PHEV as a necessary part of our strategy to
immediately begin to reverse the trend of increased oil consumption.
This will hopefully get our industry to begin to take the potential
up coming oil crisis seriously. This is the "New Game" that we all
need to focus on today!

About the author...

Professor Andrew Alfonso Frank is Director of Hybrid Vehicle Research
at the University of Californai-Davis. He holds the following
degrees: B.S. (1955), University of California, Berkeley, M.S.
(1958), University of California, Berkeley, M.S. (1965), University
of Southern California, Ph.D. (1968), University of Southern
California, Mechanical and Aeronautical Engineering.

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Felix Kramer fkramer@...
Founder California Cars Initiative
http://www.calcars.org
http://www.calcars.org/news-index.html
http://www.hybridcars.com/blogs/power
http://www.eaa-phev.org
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