Memorandum by Mr Alan L Shaw
I am aged 91 with over 35 years experience (1946-81)
as a Chartered Engineer in the large electrical power station
design and construction industry, both fossil fired and nuclear.
I served throughout World War 2 as an officer in the Royal Engineers
(2/Lt to Major) the last three and a half years in units of No.1
Electrical & Mechanical Group, Corps of Indian Engineers,
which included applications of small generating plant in primitive
conditions.
Since the Kyoto Conference I have taken a keen
interest in the UK government's energy policies relating to renewable
energy. I have noted with concern the politicisation of choices
in electricity generation. In particular I am worried about the
degree of consultation thrown open to the general public and environmental
groups whose knowledge and interest in various types of electricity
generation is mainly based on emotion, not engineering knowledge.
The result has been to encourage by large national
subsidies the excessive growth of a form of renewable energy,
viz: wind power, which is inherently uncontrollable in output,
and apply it to public electricity generation which requires above
all a demand responsive output of great flexibility.
In the early 1950s the North of Scotland Hydro-Electric
Board (with a social remit in its constitution) spent six years
attempting to apply wind power to the electrification of remote
highland and island communities centred on active operational
research on a 100kW wind turbine-generator designed and built
by John Brown's of Glasgow. They then dismantled the machine and
based developments of this type on full time diesel generation
originally intended only for back—up during low-wind periods.
Wind power was not only stated to be uneconomic but unpredictable.
I submit that all that has changed is that windpower
is now being subsidised to a level making it impossible for developers,
and their shareholders, to resist the huge profits to be made
out of a hugely over subsidised method of intermittent electricity
generation.
I mention intermittency because UK public electricity
supply is continuous 24 hours per day, 365 days a year, instantaneously
variable but within largely predictable limits. throughout the
year.
Until Kyoto UK public electricity was generated
by fully controllable means from coal, oil, hydro and nuclear
power stations, all of which can be brought on line or taken off
by the ability to control the rate of output. So how do windpower
generators fit into this pattern? The answer is that they do not.
Great Britain's mainland electricity is provided
by connecting nearly all controllable types of generation in the
form of large power stations directly to the Supergrid (400/275
kV in England & Wales, 400/275/132 kV in Scotland. Controllable
coal, oil, and nuclear fired and hydro-electric stations, all
owned by a large number of private generating companies daily
make computerised, competitive financial bids not less than a
one hour ("gate") before real time generation to the
National Grid Electricity Transmission (NGET) at its Berkshire
central control room. This is to generate blocks of electricity
specified in timing and amount and if accepted self-dispatching.
Once through the "gate" any shortfall in agreed terms
is subject to financial penalties.
NGET owns no generating plant of its own. Its
functions are to control the output of large power stations on
a second by second basis and balance demand by frequency sensitive
responsive generation brought on or off line byn themselves as
honest broker. It has a duty to admit to Supergrid connection
any generator which satifises the technical requirements of the
Grid Codes. They have no part in the forward planning of types
of generation mix.
Since denationalisation of the UK public electricity
in 1990 no one has that privilege and central electricity generation
planning has long since passed out of the hands of the highly
experienced class of electricity system engineer-managers who
fulfilled that function for 40 years before.
So where do the thousands of large wind turbines
promised to we the public actually fit in?
In the main, because of the economics of electrical
generating plant they are connected downstream of the high voltage
Supergrid and its Grid Supply Points (GSPs). There they generate
uncontrolled according to the natural variations of wind power
in the sub-Supergrid voltage Distribution Networks owned by the
fourteen Distribution Network Operators(DNOs).
Their combined variable outputs collectively
form "Embedded Generation" and act as "negative
demand" reducing, albeit instantaneously uncontrollable and
unpredictable. This "negative demand" is not seen at
national control. There the controlling, balancing parameter is
system frequency which has by law to average 50 cycles/second
annually and vary at any normal time by no more than plus or minus
one cycle per second.
So far, the percentage of national demand met
by uncontrollable has been tooo small to put the stability of
the national Supergrid / Distribution Network complex at risk
of instability such was glimpsed a couple of weeks ago.
I submit that the Select Committee on Economic
Affairs should give very high priority to consultation with National
Grid Electricity Transmission plc, its Operations Managers and
their colleagues, to form an opinion on the operational and economic
risks which will inevitably hazard in the near future the Balancing
Mechanism of the Supergrid.
16 June 2008
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