Re: Never enough biofuels to run your cars.
- From: Doug <jagmad@xxxxxxxxxx>
- Date: Fri, 6 Jun 2008 07:02:41 -0700 (PDT)
On 6 Jun, 09:57, "nightjar" <cpb@<insert my surname here>.me.uk>
wrote:
"Doug" <jag...@xxxxxxxxxx> wrote in messageYou are overly optimistic. Even so from your numbers, it would still
news:36211b3a-8516-49b2-bf77-f5bf33ef8487@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I did a quick calculation. If the entire land area of Britain,
including used by buildings etc, was given over to growing biofuels
this would only be enough to run 6million cars.
Historically, maths does not seem to have been your strong point.
Total land area 60 million acres. Area of land need to run one car for
a year = 10 acres.
So biofuels can never ever be the answer to the present level of
energy consumption. So, either reduce your consumption or continue
relying on fossil fuel until it runs out and then what?
Would you like to publish the assumptions you made to arrive at that
conclusion? Sugar Beet yields 595 gallons of ethanol per acre. 45 mpg is not
an unreasonable target for an average car, but ethanol yields about 2/3 the
energy of petrol, so, assuming 30 mpg on ethanol, that is 17,850 miles per
acre. Rapeseed oil yields 85 gallons of biodiesel per acre at 90% energy
yield, compared to conventional diesel. 60 mpg is a realistic target for a
diesel car, so taking 54 mpg for one running on pure biodiesel, that is
4,590 miles per acre. How many miles per annum do you think the average car
does?
take the entire surface area of Britain to sustain the present car
population, which I think you must agree is unworkable, especially as
it ignores all other road traffic.
What we do grow is rapeseed which is only 102 gallons/acre.
Of course, I have only taken current technology fuels and crops that will
grow in the UK. Sugarcane is a better choice than sugar beet. It produces
less ethanol, so one acre will only run the car for 16,530 miles, but it
yields 8 times the energy needed to produce it, compared to 1.9 for sugar
beet. Oil palm is the source of choice for biodiesel, as that would run the
car for 22,840 miles per acre. However, we can't grow those in the UK.
Still very much an unknown.
If we look at developing technologies, enzyme conversion of switchgrass is
expected to yield enough ethanol to run the car for 22,840 miles per acre.
Proponents of algae based biodiesel claim anticipated yields that would run
the car for between half a million and two-thirds of a million miles per
acre.
How about this?
http://www.sciencedaily.com/releases/2005/07/050705231841.htm
"Ethanol And Biodiesel From Crops Not Worth The Energy
Turning plants such as corn, soybeans and sunflowers into fuel uses
much more energy than the resulting ethanol or biodiesel generates,
according to a new Cornell University and University of California-
Berkeley study.
"There is just no energy benefit to using plant biomass for liquid
fuel," says David Pimentel, professor of ecology and agriculture at
Cornell. "These strategies are not sustainable."..."
"...In terms of energy output compared with energy input for ethanol
production, the study found that:
* corn requires 29 percent more fossil energy than the fuel produced;
* switch grass requires 45 percent more fossil energy than the fuel
produced; and
* wood biomass requires 57 percent more fossil energy than the fuel
produced.
In terms of energy output compared with the energy input for biodiesel
production, the study found that:
* soybean plants requires 27 percent more fossil energy than the fuel
produced, and
* sunflower plants requires 118 percent more fossil energy than the
fuel produced. "
Not looking good is it.
--
UK Radical Campaigns
www.zing.icom43.net
Motorists contribute to global starvation, environmental destruction
and drink driving by using ethanol.
.
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