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Going into the future, there are a number of attractive
alternate options for generating energy as well as the
way we use energy. Some of the renewable energy technologies
being talked about today may be effectively employed
at local level on a relatively small scale in rural
areas, and some of which, like PV solar, could also
be relevant to cities. One more factor that needs to
be considered is that electricity is required only in
certain applications. The bulk of local energy needs
are for heating, and there is a range of heat production
options at local level, including most obviously solar
heat collectors, but also a range of bio-fuel options.
For instance, it is possible that methane gas from
biogas generators using local wastes or local energy
crops is fed into the gas mains, and very well be used
for domestic heating and also for micro-CHP generation.
Local wastes and/or energy crops could also be converted
into liquid or gaseous bio-fuels via local pyrolysis
plants and these fuels could be used to meet local heat
needs, as well as for powering some vehicles. Certainly,
one of the still valid principles of the old alternative
technology movement is that it is environmentally helpful
to try to balance local needs with local resources.
This is likely to be much easier in terms of bio-fuels
like wood.
The 'dream solution' for wastes is to avoid both combustion
and land filling and the resultant risk of dangerous
emissions. Biogas production from farm and animal wastes
by anaerobic digestion is well established, particularly
in warmer countries, and generates fertilizer as well
as methane gas. In addition, advanced energy conversion
techniques (some using biological processes) are also
emerging, and could very well lead to commercial generation
of hydrogen gas from wastes. It could be employed to
provie healting as well as for electricity production,
for example, via a fuel cell - a device that runs something
like electrolysis in reverse, converting hydrogen to
electricity. That could even offer the possibility of
urban vehicles being run on hydrogen produced from urban
refuse.
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