This booklet is designed to provide a basic understanding of the nature
and operation of Wind Turbines. For answers to any questions not answered
here, please contact our office.
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 REQUIRMENTS 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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