RENEWABLE ENERGY; THE LIMITS?
Daniel J. Lavigne
I have updated my on-going attempt to assess the potential of
renewable energy sources. The analysis is offered as an overview of
how the field appears to me given the evidence I have been able to
get hold of to this point in time; please forward any critical
feedback or new information you see as relevant to the task.
The address for the detailed paper is
http://www.arts.unsw.edu.au/tsw/D74.RENEWABLE-ENERGY.html
Following is an outline of the conclusions; their
grounds/derivations are detailed in the paper.
- In general renewable energy sources will not be able to sustain
industrial-affluent-consumer-capitalist societies at their present
levels, let alone those economic growth will lead to.
- The crucial problems are electricity and liquid fuels. Both are
problematic but liquid fuels set the more intractable difficulties.
-Although Australia has more useful land per capita than virtually
all rich countries it will only be able to derive a small fraction of
present liquid fuel from biomass, maybe about 1/5. The main limit to
biomass energy sources is not technical efficiency etc., but what
land areas are available and what their yields might be.
- Electricity supply from solar sources must be analysed in terms of
the difficulties associated with a) winter supply and b) large scale
storage. It is misleading to think in terms of the costs of PV etc
when these sources merely feed into a coal or nuclear based grid.
A 1000MW PV power station providing 24 hour supply via hydrogen
storage (ignoring the problem of a run of cloudy days) would probably
cost more than 50 times as much as a coal-fired plant. Plausible
technical advance might cut the cost to more than 30 times.
The most intractable problem for solar energy is the "balance of
system" cost. Even if the PV technology became costless vast areas
of collecting space, structures and mechanisms would still be
required. Technical advance is not likely to reduce these costs much
as present systems are technically very simple and efficient.
- The most promising renewable technology is wind but there are
several uncertainties and limits. Some countries have large
resources; many do not. It seems that NS W, Australia's most
populated state, will only be able to get a small proportion of its
electricity from the wind, even assuming sale from the generator at
8ckWhr, 2-4 times the present price of coal-fired power.
Even where wind resources are large problems are set by variability.
In Europe summer winds are half winter wind speeds, and wind at any
one location varies significantly over time. It is not difficult to
integrate wind into grids when their contribution is small, but it is
generally estimated that the limit is c 25-35% of demand. (Obviously
a large system totally dependent on wind and able to meet demand when
winds were low would have most of its windmills idle much of the
time.) Denmark's achievements are misleading as it is able to export
much excess power to neighbours when wind are high.
Surprisingly large areas with good winds must be excluded from
generating because of other uses. This will be a significant problem
in densely populated Europe. It is less of a problem in the US
mid-west, but these resources are far from areas of highest demand,
meaning losses in transmission and high costs for transmission lines.
Easily overlooked are the long distances involved in connecting the
6000 mills spread over 2000 square km to equate to a 1000mW power
station. All these costs have to be added to mill costs in assessing
wind systems.
Very large scale systems, e.g., spanning continents, reduce the
variability problem, but set up a "moral" problem; for instance
Western Europe creaming off wind energy available between Morocco and
Kazakhstan.
- Large volume long distance transmission of hydrogen seems quite
unlikely, apart from the question of where such volumes might be
produced. Long distance high voltage DC transmission seems best, but
sets considerable costs and difficulties
The foregoing points only refer to the problem of meeting the present
global energy demand. But this is not the problem confronting the
renewable energy tech fix enthusiast -the real problem is how to meet
the demand that will be generated by the commitment to economic
growth.
At the present rate of increase in energy demand in Australia, c 2.5%
p.a., total energy demand will be 4 to 5 times as great by 2050.
(One prediction for the rate of electricity demand growth for
Victoria is 3.5%.p.a.)
-The urgency and magnitude of the problem is far greater than most
people realise. Enting concludes that even if the goal is to stop
atmospheric CO2 concentration rising above 650 ppm our carbon
emissions must be almost completely terminated for many decades and
then not allowed to rise above about 10% of the present rate. (The
goal must of course be far below 650ppm; the present 350ppm is 30%
above the pre-industrial level and alarming climatic effects are
already evident.) Clearly we should virtually abandon fossil fuels
very quickly.
-The magnitude of the foregoing numbers rules out any chance that
technical advance can solve the problems within a society that
remains committed to affluence and growth. "Factor 4" reductions
would make no significant difference; greater than factor 100
reductions would be required.
The crucial and in my view indisputable conclusion from all this is
that sustainable and just society cannot be achieved unless there is
transition to The Simpler Way, i.e, a society based on non-affluent
lifestyles, highly self-sufficient local economies, basically
cooperative systems, an economy not driven by market forces, profit
or growth and therefore quite different values. I have no doubt
that we can live very well on renewables but not within a
consumer-capitalist society.
In my view the chances of such a transition are very poor. Our best
hope lies in the extent to which the Global Alternative Society
Movement can build impressive examples of The Simpler Way within
the next few years, and contributing to that movement should be
our top priority.
For considerable material on related themes see The Simpler Way
website, http://www.arts.unsw.edu.au/tsw/
--
Ted Trainer
School of Social Work,
University of New South Wales,
Kensington. 2052. Australia.
02.93851871
Fax: 02 96628991
Email: F.Tr...@unsw.edu.au
Website: http://www.arts.unsw.edu.au/tsw/
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