Introducing
hydrogen should be an urgent business and we should work to a 20 years
timetable - not 30 to 50 years as proposed by many with vested interests
in the status quo. We have to campaign for the essential inputs that
are needed to make hydrogen happen. For example, we need to ensure the
availability as soon as possible of clean renewable electricity for
making hydrogen, but it is not always obvious what needs to be done.
For example, the UK needs to preserve coal-fired power stations to provide
low cost back-up for developing offshore wind power, but market forces
and misplaced environmental concerns are threatening coal with closure.
In the
UK it is offshore wind power and, in due course, photo-voltaics that
offer the best prospect of 100s of GigaWatts of renewable generating
capacity of electricity. All the other renewable technologies are in
a much smaller league except possibly wave and tidal stream power.
Meeting peak demand for electricity.
All of
the above technologies have a variable output. There will be calm days
when wind power will provide no generation. PV has no output at night
and declines with low levels of daylight. Tidal stream and tidal barrage
power output will vary from peak output to zero output twice a day and
at different times throughout the year as they are controlled by the
lunar cycle.
However, peak demand for electricity has to be met every day at fixed
times and, in recent years, UK peak demand in winter has been up to
53GW. At present, we have available 20 GW of gas-fired plant, 10 GW
of available nuclear, 1 GW pumped storage and possibly 2 GW via the
France connector, a total of (20+10+1+2) = 33GW plus up to 27GW of traditional
coal-fired plant inherited from the CEGB. It can be seen therefore that,
during periods of peak demand, coal generation is providing 53 - 33
= 20 GW of generation. Sometimes coal-fired stations have had to contribute
even more than 20 GW of generation due to the diversion of gas to domestic
central heating customers and the sudden failure of nuclear plant. It
is the 27 GW of available coal-fired plant that keeps the lights on
and avoids power cuts in the winter in the UK.
In the
next ten years, offshore wind power is supposed to be developed, photo-voltaics
will not yet be generally economically viable and nuclear power generation
will be reduced because of the sheer difficulties, political, material,
and personnel, of building new nuclear power stations. We should not
rely indefinitely on the France connector when France may be having
the same supply problems we have and we should not depend on gas for
more than 50% of our electricity supplies because of uncertainties both
economic and political. Also, periods of peak demand for electricity
will coincide with peak demand from gas-fired central heating customers
who are supplied by the same pipelines.
So, 10
years into the future we are likely to have the following mix of electricity
generating plant:
- Gas:
20 GW, unless we become even more dependent on future foreign gas
supplies for electricity generation in addition to domestic/commercial
heating and industrial use. Gas-fired generation will be limited by
lack of pipeline capacity to deliver more gas at times of peak demand
unlike with coal-fired generation where large reserves of coal can
be stored at the power stations. Also, if the whole of Europe has
a cold winter, then gas supplies may well be reduced completely outside
of our control whereas we can build up coal stocks.
- Nuclear:
6 GW, i.e. Sizewell B at 0.85 GW, old AGR plant and possibly some
new capacity.
- Pumped
storage: 1 GW
- Small
non-variable renewables: 2 GW i.e. sewage gas, landfill gas, waste
incineration, hydro and mini hydro.
- Coal
- Onshore
and offshore wind powered turbines and a little PV.
So, on
a cold, calm, dark day in December or January in 2012, when there will
be no out put from wind or PV, without coal we will have only (20 +
6 + 1 + 2) = 29GW of generating capacity to meet 53 GW of demand. This
could go on for a week or more!
It is assumed
in this article that improving efficiency of energy use by the end user
will offset increasing demand for electricity, so it is assumed that
peak demand will remain at 53GW.
However
on present trends of increasing demand and slow progress in improving
end user efficiency of energy use, this is a not a safe assumption.
But even on this 'best case' scenario the generation gap to be filled
by coal is 53 less 29GW = 24GW. This gap is so large that, even if some
of these figures are a little adrift, there is an indisputable need
for substantial coal-fired plant to be maintained. This is the situation
we have now in 2002 and it is not likely to change in the next ten years.
The UK is literally incapable of bridging this generation gap without
coal.
Now
consider load factors, i.e. the ratio of average output to available
generating capacity.
Over the
last two years coal-fired generation has experienced a recovery in market
share from an all time low of approx. 32% in 1999 (the effect of the
so called 'dash for gas') to 40% in 2001 due to higher gas prices, difficulties
with nuclear plant and reduced transmission from France - is this a
sign of things to come? Current annual average coal-fired generation
is about 15 GW. If we are to meet peak demand relying on coal we need
25 GW of capacity giving an annual load factor of 15 / 25 = 0.6 which,
presumably, is economically viable because plant has been brought into
service by generators to supply the market at a commercial price.
However,
the downside of this increase in coal burning is increased CO2 emissions
which is making it more difficult to meet Kyoto climate change obligations.
This could be used as an argument for building more nuclear power stations
to replace coal. But nuclear power economics require base load working
because nuclear plant is so expensive it has to run 24 hours a day to
cover its costs; this means a load factor of 1 which means no spare
capacity to back up renewables.
So,
if existing coal-fired power stations are replaced by new nuclear power
stations to reduce CO2, we will lose the 10 GW of spare generating capacity
to back up wind power and photo-voltaics. These renewables will not
then be developed and we will never control CO2 because nuclear power
is only a minor player in the long run.
It will
take 10 years to get one Sizewell B nuclear power station (output 0.85
GW) built; it will then take many years to payback the CO2 produced
by its construction. But, if we start building wind farms onshore today,
they will be generating next year and will have repaid their construction
CO2 the year after. To equal Sizewell B will require 1275 2MW turbines.
If, for example, these turbines were in one farm offshore they would
occupy a patch of the North Sea measuring 7.5 by 7.5 miles.
15 GW of coal generation requires about 50 million tons of coal per
year, so this is why we still have a coal industry; we should maintain
both. If we were to lose our coal mining industry, it would be impossible
to restart it if the need arose because we would have no UK miners or
mining expertise.
The popular
view that dirty old coal should be phased out is wrong. Coal may produce
relatively high levels of CO2 but, if it is used as part of an integrated
low emission system to back up zero-CO2 renewables like wind and PV,
then the production of CO2 from the combined system can easily be reduced
by over 60% of 1990 levels as required by the Royal Commission on Atmospheric
Pollution report.
Conclusion
The UK
government should support coal for the reasons described above. We may
be living in a market economy now, but it would be foolish to throw
the baby, i.e. coal, out with the CO2 bathwater. Also, new clean coal
burning technologies will produce much less CO2 per unit of electricity
generated.
If necessary,
coal should be subsidised or given a guaranteed market share to ensure
its survival as an essential part of the transition to an integrated
clean energy system for electricity generation, transport fuels and
heating based on variable renewable energy supplies. Nuclear power does
not provide this opportunity for transition. Coal and renewables together
will lead to a low CO2 emissions future whereas more new nuclear power
stations lead nowhere in the longer term.
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