Memorandum submitted by Tom Midgley
An objection often raised against the widespread
use of renewable power sources is that they are not guaranteed
to be constantly available. I would like to put to the committee
the thought that matching supply to demand is inevitably a complex
business, and that while variable supply increases that complexity
it is not beyond the wit of man.
NEED FOR
AN ANALYTICAL
MODEL FOR
POWER AVAILABILITY
AND DEMAND
Our electricity supply system has been built
around the reality that demand for power varies through the day,
from day to day, geographically, and with the seasons. The current
design of the electricity system assumes that supply will be constantly
available and—for the most part—controllable[204].
This is not a necessary assumption. Many of
the natural power sources available to us—wind, wave, solar—are
neither constant nor controllable, and if we are to make best
use of them rethinking and redesign will obviously be necessary.
If we move from a few, large, controllable generators
to a many, smaller sources with time-varying outputs, it becomes
a statistical question what mix of technologies will best provide
electricity at an appropriate service level.
It might be for example that a certain mix of
wind and solar power would require backup from coal-fired stations
on 14 days of the year to meet demand, but that by substituting
some wave power this would be reduced to five days.
I would hope that this committee would be able
to recommend that analytical tools should be developed, able to
establish the optimal mix of power sources to provide a defined
level of security of supply, taking into account the statistical
distribution of the supply technologies—wind, wave, solar—and
the daily and seasonal demand for electricity.
Whilst our requirement is to perform this analysis
for the UK, the optimum mix will be very different in other parts
of the world, and we would render the world an enormous service
if our analysis were done in such a way that the different parameters
of each country could be simply "plugged in". Thus,
in the UK an important factor is the wintertime correlation between
the high demand for heat and the peak availability of wave power,
in Bahrain the simultaneous demand for air-conditioning and the
availability of solar electricity would be more significant.
22 September 2005
204 The exception of course is Nuclear Generation
which is extremely inflexible, hence the millions of night-storage
heaters which were installed to try to use the output at times
of low demand. Back
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