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About Wind Turbines |
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Global Warming
The growing concern about Global Warming and
Greenhouse gas production has lead Governments
worldwide to consider clean alternatives to Coal
and Diesel for the production of electricity.
Australians are the worst greenhouse gas
emitters in the world. 43% of Victoria’s
emissions are produced by the burning of brown
coal for the production of electricity. The
Australian Government has set a requirement that
by 2010 Renewable Energy will provide 9500
gigawatt hours of electricity per year. This
equates to approximately 4000 megawatts of
installed capacity of Renewable Energy sources
or the equivalent of two Loy Yang A power
stations. Renewable Energy is clean energy and
is as close to greenhouse gas neutral as it is
possible to achieve.
Why Wind
What about Solar Power, Hydropower and
Biomass.
- Solar electricity is currently very
expensive (about $13 per watt installed) And
there is no sign of solar getting any
cheaper, in fact all suppliers of solar
panels have recently increased their prices.
While well suited to applications such as
remote homes, remote communications and
navigation aids for instance, the cost and
payback period for grid connected solar is
not viable without government grants.
- Hydro electricity is by far the most
cost effective form of Renewable Energy,
however Government policy is that no new
dams will be built for Hydro, so the only
opportunities are to install Hydro Turbines
on existing infrastructure or dams , these
opportunities are few and far between and
will not be enough to meet the requirement.
- Biomass covers a wide range of energy
sources and technologies, from burning
household rubbish to make steam for the
generation of electricity to growing crops
to burn or to produce oil (i.e. Canola oil)
which when treated can be used as a Diesel
substitute. The economies of these
technologies have yet to be proven.
WIND ENERGY IS PROVEN TECHNOLOGY
Some European countries have had Wind Turbines
in operation for over 20 years. Wind Energy
production costs in Europe are now competing
with coal fired power stations. Since 1990 the
Wind Energy Industry has been the fastest
growing sector of the power generation industry
and continues to be so. Large scale Wind
Turbines can be installed for about $2.00 per
watt or about two million dollars per megawatt.
A typical Wind Farm will use about 1% of the
area where it is constructed leaving the rest
for normal farming or grazing practices. Wind
Turbines have a designed working life of 20 to
25 years and require very little maintenance
during this time. Wind Turbines are safe, there
has been no recorded injury to a member of the
general public anywhere in the world.
WIND TURBINES
Wind Turbines will typically be installed in
small groups of 2 to 5 units connected to the
existing utility grid, or in larger groups of
10 to 30 units with a dedicated transmission
line to a suitable connection point at a nearby
high voltage cable or switchyard. The Turbine
consists of a large set of 3 blades which drive
a generator via a large gearbox, this is
installed in a nacelle which is mounted on a
powered turntable at the top of a tall tower.
(see fig 1) When the wind speed increases above
a certain speed , known as the cut in speed
typically about 3 to 4m/s (meters per second)
The Turbine will begin to generate electricity,
and will continue to do so until the wind speed
reaches the cut out speed, (about 25m/s) at this
point the turbine will shut down, rotate out of
the wind and wait for the wind speed to drop to
a suitable speed to allow the Turbine to start
again. The Turbine will have an optimum
operating wind speed at which maximum output
will be achieved, this is typically about 13 to
16m/s During operation the generator ensures
that the blades maintain a constant speed of
about 20 revolutions per minute, which the
gearbox transforms into 1500 revolutions per
minute. Higher wind loads acting on the blades
result in increased power production but not a
higher number of revolutions per minute.
HOW BIG
Wind Turbines are big (see fig 3) a typical
Turbine of the size to be used in Australia will
be installed on a tower which is between 50
meters (150 feet) and 80 meters (240 feet)
tall. The rotor diameter (blade span) will be
between 50 meters (150 feet) and 80 meters (240
feet).
Turbine towers are constructed from rolled steel
plate and are normally about 4 to 5 meters (12
to 15 feet) diameter at the base and about 2 to
3 meters (6 to 9 feet) diameter at the top.
Turbines are installed on concrete foundations
that are buried well below ground level with a
pedestal to mount the tower on so the landholder
can work the land right up to the base of the
tower.
NOISE
Wind turbines are not noisy ; a typical 1.5
megawatt (15,000,000 watt) Turbine, similar to
the Turbines installed at Codrington and Toora
will produce 45dB(A)
or less at 300 meters. This noise level is about
the same noise level you will hear sitting in
your kitchen listening to your fridge. The
average noise level in a typical home is
50dB(A). However this is only the noise produced
by the Turbine, the natural wind rush noise is
heard as well and this is normally about 40dB(A)
so the end result at a typical exclusion
distance of 300 to 400 meters is that the
Turbines are almost inaudible. Some Turbines
produce up to 100dB(A) but this is measured at
the gearbox at the top of the tower. The fact is
that with the turbine running at its rated speed
a normal conversation can held at the base of
the tower. This can be proven quite easily by
visiting one of the existing Wind Farms and
hearing for yourself.
EMBODIED ENERGY
A typical large Wind Turbine will recover the
energy used to manufacture and construct it
(embodied energy) in 4 to 5 months of operation
in a reasonable wind regime. It should be
remembered that a coal fired power station never
recovers the energy used to construct and
operate it as these power stations have a
continuing requirement for very large amounts of
energy to operate.
WIND TURBINES WILL NOT REPLACE COAL POWER STATIONS
Wind as we all know is neither constant or
consistent but society requires an electricity
supply that is , so base load power stations
will always be required.
What Wind and other Renewable Energy sources can
do is supplement these base load power stations
and reduce the consumption of coal and therefore
emissions. Wind Turbines have never caused an
existing power station to close down, but it has
meant that in countries like Denmark, Holland,
Spain, Italy and Germany new coal fired power
stations do not need to be built. Germany is
oneof the largest users of Wind Energy with
6113megawatts of Wind Turbines installed, this
is assisting the German Government to close its
nuclear power stations. The Danish Government
has determined that Wind Energy will provide 50%
of the countries energy requirements by 2030;
this means a 50% reduction in greenhouse
emissions if this Energy was sourced from coal
power stations.
In Victoria the brown coal power stations of the
LaTrobe Valley produce almost 10% of Australia’s
CO2 emissions or 2kg of CO2
for every kilowatt hour of electricity produced.
BIRDS
Wind Turbines pose little threat to birds, there
is little real evidence here or overseas that
bird strikes on Wind Turbines present any real
problem providing the Turbines are placed with
care and thought. The Americans who in the 80’s
built several Wind Farms in California have
largely caused the concern regarding bird
strikes. These Wind Farms were built without
consideration of aesthetic or environmental
issues and caused many problems including bird
kills. The Wind industry worldwide has learnt
from this experience and no reputable Wind Farm
Developer would consider the wall to wall Wind
Turbine option. It is unlikely that any Council
or State Government would allow this type of
development. If we are really concerned about
the plight of Birds perhaps we should be looking
at Cats, Cars and power lines.
CAPACITY FACTOR
Capacity factor, sometimes called load factor is
the amount of time an energy production source
is able to produce electricity. A coal power
station will have a capacity factor of 65 to 85%
that is, it will be able to produce output for
65 to 85% of the time, it will be out of action
the rest of the time due to maintenance, labor
strikes, breakdowns etc. A typical Wind Turbine
will have a capacity factor of 25 to 40%
depending on the available wind resource.
Currently in Australia a Wind Farm will need a
capacity factor of 32% or better to be viable.
WHAT DOES HAVING WIND TURBINES ON YOUR
PROPERTY MEAN TO YOU
For some people the greatest benefit of having
Wind Turbines on their property will be the
contribution to reducing greenhouse gas
emissions and for others it will be the
guaranteed income for the life of the Turbines
(20 to 25 years) Currently you could expect up
to $3000 per megawatt installed (or part there
off ) per annum with no outgoings at all. The
process of establishing Wind Turbines can be a
drawn out affair and may take 2 to 3 years from
first contact to construction and commissioning.
The following steps will need to be undertaken
prior to construction.
Land holder agreements and contracts.
This usually means you will be asked to commit
to allow your site to be monitored for Wind with
the option to negotiate a contract to proceed to
construct Wind Turbines If the results of the
monitoring prove satisfactory. These initial
agreements are usually for 3 to 5 years. The
agreements are flexible and allow the land
holder to apply conditions to the agreement.
I.e. prior notification of a visit, gates must
be closed, cars must follow tracks etc.
Site Monitoring
This normally requires
The installation of a temporary mast the same
height as the proposed Turbines hub, (known as
hub height)
This will be between 50 and 80 meters (150 to
240 feet) This mast will be equipped with one or
more wind monitoring instruments, these will
relay data to a recording device (logger) at the
base of the mast.
The stored data will be down loaded about once
per month. No input is required from the land
holder. The mast is normally guyed and as long
as the guy anchor points are fenced to avoid
cattle rubbing and stretching the guy’s, the
mast should not interfere with normal use of the
land.
Monitoring will most often take 12 months but
may only be 6 months if there is a reference
point nearby.
Operation and Maintenance
Once the Wind Turbines have been
commissioned it will operate with little human
intervention. All monitoring and adjustments can
be made remotely via a computer, staff will
visit the Turbine to perform routine maintenance
as required.
PERMITS, STATUTORY REQUIREMENTS AND COMMON SENSE
Once a site has been proven a number of
statutory requirements will need to be
undertaken as well as matters of common sense
and common courtesy. These will include but may
not be limited to the following.
- Consultation with neighbors and nearby
residents.
- Consultation with local community.
- Consultation with local indigenous
groups.
- Consultation with the Council.
- The undertaking of an environmental
effects study
- A study into Flora and Fauna (birds)
issues.
- Native title issues.
- Planning and permitting.
This process may take up to 2 years or more but
is likely to be 12 to 18 months.
Construction
When a permit is issued, construction will
commence. Soil testing will be undertaken to
determine the type of foundation required for
the Turbine towers and in consultation with the
land holder access tracks will be formed to
allow heavy construction equipment to enter the
site. These tracks and earthworks can be left
when construction is complete for farm use or
the ground reinstated to it’s original state.
Once the foundations have cured construction is
quite rapid and a Turbine can be erected in 1 or
2 days with another 2 or 3 days for commissiong
a small area will be required for the
installation of the transformers and switchyard.
This area will be fenced with chain wire and
present no hazard to man or beast.
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