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THE CYCLE – REDUCE
KICK THE HABIT
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why not save energy by simply running in the park? You do some shopping
on the way home. Are you concerned to choose food that is in season, has
not had to be kept frozen for months and is not
over-packed
in climate-
hostile material? Home for dinner, and you may decide it is simpler and
quicker to thaw some frozen vegetables, instead of cooking fresh ones on
the stove. Doing the laundry means still more decisions: do you use a high
temperature wash or choose a lower one that takes less power? Do you
use the tumble dryer or leave the washing to dry on a clothesline? The
evening is for watching TV. Hopefully it has not been on stand-by all day
long, together with the DSL modem, the DVD player and the stereo. Before
bed you check your emails: perhaps you have read the warning from one
industry figure, that worldwide internet usage alone needs the equivalent
of 14 power stations for the necessary computers and servers.
The net result of the exercise is perhaps surprising. Someone who does not
think about the climate impact of the way they live would be responsible
for emissions of about 38 kg of CO
2
for a day like this. Yet somebody who
thought hard could enjoy virtually the same level of comfort for a much
more modest CO
2
burden of 14 kg. Often that is all it takes – a conscious
effort to think about the impact we are having.
Reducing GHG emissions from waste is about capturing methane generated in the
landfill through the decomposition of organic materials such as food scraps, garden
waste and paper. Sewage and wastewater treatment plants also release methane
when they break down waste.
Reduction of GHG emissions from waste can be achieved by utilising the an-
aerobic digestion (AD) process caused by bacteria in the absence of oxygen, for
biogas production. Biogas consists mainly of methane (around 60 per cent) and
CO
2
(around 40 per cent) (with traces of hydrogen sulphide and ammonia). The
process is exactly the same as occurs in the landfill anyway, but under controlled
conditions. The biogas can be used for electricity and heat generation. The main
limitations of such a process are high capital and operating costs, especially at
large scales. Successful energy generation depends on providing a continuous sup-
ply, adequate storage and reduced transport requirements (so the schemes should
be mainly local).
In theory, well-managed waste incineration plants and biogas production from
disposal sites are valuable energy sources. But the technology needs to be applied
more widely until uncontrolled dumps disappear. What is more worrying is exces-
sive waste generation itself: finite resources are transformed into single-use, GHG-
emitting goods that all too quickly end up in landfills.