|
From the Library Shelf:
Proud Co-Founders of Transition Town High Wycombe
We are supporting Transition Thame & District:
and Transition Town Marlow:
|
Growing Gas - Horror or Saviour?
|
 |
|
Much of the hype &
hysteria concerning bio-fuels has been driven by two opposing
camps. In one corner we have the politicians who see votes in
being able to suggest that everyone can continue their luxurious
business-as-usual lifestyle by filling up their 4x4's with
bio-fuel. In the other camp are the
super-greens who cite the destruction of ancient forest in order
to grow bio-fuels in the third-world. Well, what are we to make
of this?
Biofuels will never
replace our bountiful oil endowment due to the fundamental laws
of physics. Photosynthesis is simply not efficient enough to
capture THAT amount of energy in a short amount of time.
However, there is some good news. We should not throw baby out
with the bath water. Biofuels do have a future, even if the
private car does not. Read
on... |
The Coming New Reality
|
|
 Forget filling
up your car with biofuel. Forget it forever. It ain't gonna
happen. It took mother nature billions of years to store
away our oil endowment through a process that started with
simple photosynthesis. This captures the sun's energy as
chemical energy. It is a chemical battery. Millions of years
if pressure and heat underground has made the molecules line
up in this chemical soup in all kinds of interesting ways.
You'd be crazy to just burn it. Yet that is what we do. It
all goes up in smoke. It would take 400 years of
photosynthesis to capture all that energy that you release
in just one year of your human activity. So there is no
chance that plant matter is going to start compressing 400
years worth of photosynthesis into one.
It just doesn't
stack up. The second thing to realise is that we are only
able to make vast quantities of biofuel by burning vast
quantities of fossil fuel. Some critics claim it even takes
one barrel of oil to make one barrel of biofuels. This may
not be quite true but the process is certainly low-yield and
energy intensive. Even worse than that - it is going to
compete for land with our need to grow food. What would you
rather do? Drive your 4x4 and starve. Or eat? Rich
westerners may get the luxury of a choice but poor
southerners may not. They may face food poverty so that rich
men can drive.
These options
are unacceptable. However, in a low carbon-society, like
the one proposed by "Zero Carbon Britain" the biofuel has a
place. Principally it will be bio-diesel that drives farm
machinery. It is claimed that Britain can easily produce
enough biodiesel from rape oil to fuel its farm machinery.
This comes to 13TWh (terra-watt-hours). Even more is
expected from forestry and Miscanthus ("elephant-grass"). This should provide
335 TWh of energy that could be used in Combined Heat Power
plants. 17 TWh will also be available from straw. By 2027
the total annual output will be 25 TWh. This could make
agriculture self-sufficient from foreign oil-imports and,
 essentially, carbon-neutral.
The point to
remember about the 'Island Britain' idea proposed by Zero
Carbon Britain, is that it proposes complete self
sufficiency from oil imports. Hence there will be wide scale
carbon rationing and no private motor cars driven by petrol
or diesel. Everyone will use public transport or drive an
electric car. This vision for Britain is revolutionary and
probably quite shocking to many. Farming will be mostly
organic and very little meat will be produced as it is too
carbon-intensive. Instead land will be put to better use
growing crops or forest. Such a future has us warm and well
fed... But it is nothing like what we have today. Some may
view this as a fantasy. |
Land for Biofuel Crops
|
|
 Simple calculations
show that biofuels come nowhere near providing enough fuel for
all the World's current transport demands. As mentioned,
photosynthesis is simply not efficient enough for such an
absurd undertaking (unless you have access to a time-machine).
For a given area wind-turbines produce 20 times more energy
whilst photovoltaic panels generate 100 times more. Biomass
crops need a lot of land.
In the current
period of 'Globalisation' rich westerners in the north tend to
just export this problem to some poor third world country. There
is little point clearing a forest to grow bio-fuels if that
forest would have absorbed more CO2 if you left it as it was.
Even if we don't export these problems abroad then our current
model of agriculture suggests we apply liberal amounts of
oil-made fertiliser to everything to make it grow bigger. When
taken into account this means there is little or no net saving
in fossil fuels.
However if we adopt
organic farming practices there is a future for some biofuels
near to where they will be used. Biofuel can be sourced from
short-rotation forest, coppice and arable land. Rotation farming
is a traditional way of using 'break' crops to maintain the
health of the soil. Hence bio-diesel may be the by-product of a
farming practice we will have to adopt anyway when the fossil
oil runs out.
 We mentioned
Miscanthus earlier. What is that? Well it is perennial grass
that can be under sown with clover to improve nitrogen fixation.
Successive harvests of Miscanthus deplete soil nutrients very
little but improve soil structure. In some areas hemp can be
used instead. And Miscanthus is a fuel crop. In future it is
thought that wood from a forest
could be processed into a liquid
or gaseous biofuel that displaces fossil fuels, leaving a char
residue that can be returned to the soil, where it improves
yields. This process also sequesters carbon at a rate much
greater than that of traditional humus.
However good this
sounds it only works within the framework of a radical overhaul
of the way farming works in the North. Welcome to the real
world.
|
Biofuel from Recycled Waste
|
|
So, is there any
good news about Biofuels? Of course there is. It doesn't have to
be made from virgin product at all. In 2003 the UK produced
100,000 tonnes of waste vegetable oil (think chip fat). Enough
for 110 million litres of biodiesel. Add in all the other waste
oil that ends up poured down the drain and you can double this
number. The same again is available if we converted all those
used car tyres in to biodiesel via the process of pyrolysis.
There is also biogas from the anaerobic digestion of the 6.7
million tonnes of food we throw away every year in the UK. There
is enough there for 209 million cubic metres of fuel. If the UK
treated sewerage through anaerobic digesters it would produce a
net annual methane supply of 123,750,000 cubic metres.
Now all of this
biofuel is only enough to supply about 3% of our current
transport fuel consumption. However, the UK's Bus Fleet used 1.8
billion litres of diesel in 2006. So a full 20% of all buses
could run on carbon-neutral sustainable bio-fuel. |
Post-Carbon Girl
|
Resource
|
 Heah! I am reading the Mobbs book on "Energy Beyond Oil".
Well, in truth Daddy is reading it and telling me all about
it. I can't believe that we can turn plants into oil! Isn't
that great? Daddy says, no Mila, that isn't so great. There
will never be enough plants for us all to drive. Eat them
and pedal he says! |
-
www.zerocarbonbritain.com - a web site by the Center for
Alternative Technology that presents a plan to have Britain Carbon Neutral by 2027
|
Conclusion
|
|
|
|
|
|
|
| References: |
- Much of this data has been culled from the
ZeroCarbonBritain Report which you can download and read for
free at
www.zerocarbonbritain.com
- "The Ecologist" Magazine October 2008 article
"Excremental Changes"
- "The Ecologist" Magazine February 2009 article "Biofuels
2.0"
|
| |
|
|
|
|
