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Ten!...Nine!....Eight!....the spectators shouted the count-down until Nancy Hazard dropped the checkered flag in front of six unusual cars. Without the screech of tires, the One Gallon Challenge began in stately, fuel-conserving style, as each car set
out to drive the 100 miles from Greenfield, Mass. to Boston on one gallon of fuel.
As the cars pulled into the Greenfest festival in downtown Boston later that afternoon, after blisteringly hot weather and many adventures, each had proven some aspect
of our complex evolution to ultra-economical transportation:
Dirigo--a sleek diesel 3 wheeler clocked in at 88MPGe with a running cost of 2.9 cents per mile--showed the importance of good aerodynamics. This car had no backup, but was driven 550 miles on its own tires! With a sigh of relief, Bill Buchholz finally pointed the hood ornament toward Maine:
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The wood-gas
powered truck from 21st Century Motor Works breezed in at 27.7 MPGe and an amazing 1.7 cents per mile travel cost, showing the viability of using a local, carbon-sequestering fuel source: ordinary cord wood.
MIT's Electric Vehicle Team drove their Porsche at an amazing 164 MPGe (plug-to-wheels) and 75MPGe (wells-to-wheels)
efficiency.
Once our electricity grid becomes more earth-friendly, this technology may surpass all others. Many spectators, used to lead-acid technology, were awed as these students drove, with 18 automotive-sized Lithium-ion batteries donated by Valence Technology,
from Cambridge to Greenfield
on a single charge, then charged up at the Ford dealership, and merrily drove back home. Without a doubt, the miracle battery we all dreamed of decades ago has arrived.
 
The Roopod, poster-child of the event, was not quite drivable at race time,
but was pushed symbolically across the start, and was on display in Boston.
This ultra sleek and light 14 HP diesel-powered wonder will be a car to be reckoned
with next year.
Dripping with sweat, Jory Squibb drove his gas-powered three-wheel Moonbeam across the line at 93 MPGe and 2.7 cents per mile cost. Built as a grocery-getter, it had never been driven far from Camden, Maine; but finished the race without incident, blasting its heater to keep the engine cool in the 90 degree heat.
Though they were weary after interacting with the thousands of attendees at the two-day Greenfest,
all participants agreed to return next year with exciting improvements and face an even larger field of next-generation vehicles.
Here are the placards displayed at the greenfest,
and the way the efficiency was calculated:
THIS CAR’S
EFFICIENCY
DRIVING FROM GREENFIELD, MASS THURSDAY, I DROVE ________MILES
EXACT AMOUNT
AND TYPE OF FUEL USED FOR THE TRIP
___________________________________
THIS REPRESENTS AN EQUIVALENT
GASOLINE EFFICIENCY OF
________MPG
USING THE PRESENT COST OF MY FUEL(S), THE TRIP COST
__________CENTS/MILE
CAR DETAILS:
Propulsion__________________________
Built by ____________________________
____________________________________
Interesting details__________________________________________________________________________________________________________________________________________
CALCULATING EFFICIENCY.
If you used gasoline, simply divide miles by gallons
If you used diesel, divide miles
by gallons and multiply by 0.95
If you used electricity, divide KWH used by 33.7 to get equivalent
gas used.
Then, divide miles driven by this equivalent gas used. This will give you a plug-to-wheels figure.
This plug-to-wheels figure does not account for the resource consumption
(and carbon generation) of electricity. Multiplying the plug-to-wheels figure by .46 will
adjust
for the relative efficiencies of supplying electricity-to-plug vs gasoline-to-pump.
See below for details
If you used wood and gasoline take pounds of wood you used and divide
it by 13. This converts wood energy to gasoline gallons. Then add the
gallons ofgasoline you used. Divide the miles driven by this total gasoline to get MPGe.
In energy conversions, the major losses occur where the fuel burns. Thus, in generating electricity, the major losses are at the power plant. In a gasoline-powered car, the major losses are in the car engine. Averaged over all sources, and throughout the US, electricity is generated, and distributed to wall outlets, at 38% efficiency. Gasoline is refined and transported to the pump with 82% efficiency.
.38/.82
=.46, an adjustment figure for the relative efficiencies.
Because electric motors are highly efficient, electric cars are still very efficient after applying this adjustment.
(courtesy Ken Fry)
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