When we walk out our doors in 20 years to take a drive, what kind of a vehicle will we get in?

The preferred answer, of course, is a pair of sturdy shoes or a well-maintained bike. But the reality is that at least for next couple decades, personal motorized mobility (a.k.a. cars) will be some part of the mix. So how do we do them right?

We're looking more and more at the combination of electric vehicles, smart grids, product-service systems and good urban development as a means of restructuring our personal transportation options and impacts.

Now, WWF has published a pretty good summary of the case for plug-in vehicles (all-electric or hybrid), from an emissions and energy security stand-point.

Here, essentially, is the main take-away:

Electric vehicles are highly energy efficient Grid-connected vehicle technology – enabling all or part of every jour- ney to be powered by electricity taken from the grid – is available based on existing infrastructure and current technology. Battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs) – which may be sup- plemented by sustainable biofuels for range extension – can dramatically reduce the crude oil dependency of automotive transport in a highly ef- ficient and sustainable manner.

Electric vehicles still need energy, and that energy today comes mostly
from fossil fuels. However, the electric powertrain is up to four times more
efficient than its conventional mechanical counterpart. This means electric
vehicles consume far less primary energy per kilometre travelled, so that
even based on today’s fossil-rich energy mix, electric vehicles can deliver an
overall reduction of greenhouse gas emissions. In addition, electric vehicles
can contribute to improving urban air quality and reduce noise levels.

For any given resource, electricity beats liquid fuels
Whether the starting point is crude oil, natural gas, coal, or biomass,
electric vehicles will emit fewer GHG emissions per kilometre travelled
than their conventional mechanical rivals. For example, the latest coal-
fired power plants can deliver three times as many automotive kilome-
tres as CTL plants, for the same life-cycle CO2 emissions. Thus there
can be no rational argument for CTL programmes on the grounds of
energy security, nor climate security.

The whole report is worth a read if you're interested in these questions.

Note that be best commercial power generators work at about a 40% efficiency which means that approximately 60% if the energy in the raw fuel goes up the smokestack. That this is much better than the efficiency of the normal gasolene or even diesel engine is an indictment of the latter as efficiency deficients. Part of that deficiency is due to the inherent requirements placed on car motors: to be able to accelerate rapidly (most inefficient, as evinced by the smoke coming from the tailpipe of a rapidly accelerating vehicle) as well as maintain a constant speed (most efficient, except) under varying loads (hills, number of passengers, weight of goods, etc.).

However, there is now a home heating system built by a company called Climate Energy which burns natural gas in a Honda generator of electricity to power a house, but collects the heat from the exhaust to heat the house, either by heating the air (furnace) or by heating water (hydronic). This system captures up to or exceeding 90% of the energy in the natural gas, thus far exceeding the efficiency of the grid power station. When the generated electricity exceeds the demands of the house, it can be sold back to the local Utility for use by other consumers. Thus the homeowner can effectively generate up to the total electrical load of the house while heating the house -- thus much or most of the electrical bill can be zeroed during the winter. What prevents the homeowner from selling more power to the utility is the currently accepted principle that the consumer is not a power generator or utility, but just a consumer that can bank some of his own power out on the grid for a short time (a billing cycle in Massachusetts, other periods and amounts, etc., in other states).

Posted by: Donald B on April 19, 2008 7:20 PM

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