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1 December 2008
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Practically all of Cyprus' electricity is
generated by oil-fired power stations. The total current capacity is
about 1 300 MW and the peak demand approaches this value. This leaves
insufficient reserve in the event of a major breakdown in hot weather,
when the demand is highest. It is recognised that an increase of
capacity is required within a few years.
The average demand is increasing at
a rate of nearly 10 per cent per annum while the rate of growth
for peak demand is less predictable, because it is
weather-dependent. If the peak demand exceeds the supply or if
there is a breakdown in generating capacity or distribution, the
only solutions are either a 'brown-out' if the shortfall is
small or regional black-outs. (A brown-out is where the voltage
drops to about 210 V or less, a black-out being where the power
supply is cut completely.) As Cyprus becomes more industrialised
with greater potential
tourism and homes are equipped with more appliances, the demand is
expected to continue to increase over the next decade. More capacity is
therefore very necessary.
Ideally, the current structure could be
complemented by an increase of the use of renewable sources (see the essay
on Renewable Energy). It is doubtful whether these could provide more than
an extra 50 MW, in the short term, mostly solar PV generation and by
enhancing the value of waste. This would be useful as at least half of this
would be generated when the peak demand is highest (unfortunately, though,
the efficiency of solar panels drops when the temperature is high). If one
or more
waste enhancing power stations were built and the necessary collection
infrastructure implemented, then the total capacity could be increased by a
further 100 MW. This would have other environmental advantages.
However, none of these measures will be
sufficient in the long term (say, within a decade) and demand will outstrip
the expected supply. It is therefore necessary to envisage the construction
of new power stations. This is exacerbated by the requirement to reduce
carbon dioxide emissions from current oil-burning ones (see the essay on
Climate change). How can this be achieved?
The ability to convert existing power stations
from oil-burning is very limited. At the best, the more modern plants could
be converted to burn methane (natural gas). This would reduce the carbon
dioxide emissions by up to about 10 percent per kWh but at the cost of a
significantly increased concomitant emission of methane at all stages of
production of the gas. Because methane is a bad greenhouse gas, much worse
than carbon dioxide, this would actually be environmentally negative (see
the essay on natural
gas)). However, major changes to the thermal design of the plant would be
necessary; gas is not a "drop-in" substitute for oil. Notably, the stack
gases would contain much higher levels of water vapour. Other infrastructure
changes would be the provision of high-pressure, insulated, liquid gas
reservoirs at -164°C and the means of filling them from ships, along with
capitally expensive regasification plants. Alternatively, compressed natural
gas has been suggested, but this seems even less viable, although at a
better scale for the island.
Biological methane would seem even less likely to be useful. Worse, it
requires considerable energy to liquefy or compress the natural gas and to
transport it from the producer to this island, all of which will also come
from fossil fuels and will contribute to carbon dioxide emissions.
New power generating capacity must be built.
The big question is what type?
This is the obvious and easy method, but there
are four serious disadvantages that must be taken into consideration:
-
natural gas combustion produces carbon
dioxide emissions, responsible for climate change. For each kilogram of
natural gas burnt, nearly 2¾ kilograms of carbon dioxide is emitted.
-
tthe supply of natural gas is limited, the
bulk coming from politically volatile Middle and Far Eastern countries
and Russia: supply is therefore impossible to guarantee and the price is
sure to rise drastically as reserves dwindle and as
oil becomes scarcer
-
supply is dependent on special tanker
ships, which are limited in number
-
natural gas is inherently a
bad greenhouse
gas and emissions from the wellhead to the power station are
inevitable
TThere are two kinds of gas-fired stations:
conventional thermal types with a boiler driving a steam turbine and
direct-fired gas turbines. The latter has the advantages that they are more
efficient and, in the event of a breakdown, a loss of wind or sun, or a
sudden increase in demand, they can be brought on line in a very short time:
this makes for the ideal back-up method without the need to idle
conventional thermal systems.
Planning applications have been
made for an off-shore 200 MW platform power station to be built,
close to assiliou
power station. I must admit that the cost of this must be considerably
higher than a traditional land-based one, which makes me wonder what the
advantages could be, especially as the promoters state that LNG tankers
would need to shuttle to it only once every 80 days. I also wonder whether
it would affect the amenities in the Governor's Beach area.
Of course, electricity should not
be wasted. If it is, it is costly and polluting. It therefore behoves every
user to use this source of energy as economically as possible. There are
various ways of doing this:
-
use low-energy light bulbs
-
switch off lights when not
required for more than 3 minutes
-
switch off all appliances not
in use
-
keep constant room and water
temperatures but switch off at night
-
set the thermostat of
immersion heaters to 50 - 55°C
-
ventilate rooms minimally
-
ffor electric room heating, use
the air conditioner in 'heat' mode to rapidly bring a room up to a
comfortable temperature, rather than a fan convector or heater
-
consider
night-storage heaters rather than fan convectors or other
heaters (these have the advantage that they 'burn'
electricity when the supply is much greater than the demand
and the power stations are producing their background levels
of emissions; the extra load makes almost no difference to
the pollution. The cost of energy is also reduced on Tariff
55.)
-
consider heat pump
central heating.
-
run irrigation
pumps at night (this also conserves water)
-
use thermostatted electric
heating to a maximum of 20°C in living rooms and 18°C in bedrooms
-
use thermostatted
air-conditioning to 28°C in summer for only a minimum time
-
improve
house insulation
-
purchase low-consumption
appliances
Future electricity supplies in
Cyprus are a thorny problem that cannot be resolved by half-measures. All
parties, including the public, must take the bull by the horns. Conservation
is important, as are renewable supplies, where these are feasible. Demand
will foreseeably rise to over twice the current peak requirements within a
decade, probably sooner. Decisions must be made as to how this will be done,
even if they are unpopular.
The following three references are
EU publications, impartially putting forth the advantages and disadvantages
of nuclear power:
Nuclear energy: the benefits of an unpopular sector
Nuclear energy: there are risks and risks
Nuclear energy: waste management, a crucial matter
The following summarises the
problems and solutions for an "environmentally-friendly" supply of
electricity:
The salient points
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