Mighty River Power Limited is a state owned enterprise that
operates nine hydro-power stations and dams on the Waikato River.
Mighty River Power also has interests in geothermal generation
at Rotokawa and Mokai, and is the leading supplier of electricity
from methane gas produced at landfill sites in Auckland and
the Hutt Valley. It also owns a natural gas fuelled, co-generation
plant at Southdown in Auckland.
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 1.
Generation
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Electricity is generated when a loop of conducting
wire rotates in a magnetic field. In a hydroelectric
plant, water from a dam turns turbines that spin the
generators that produce electricity. The electricity
flows to a transmission substation where a transformer
changes a large current and low voltage into a small
current and high voltage. |
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2.
Transmission Substation
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The transmission substation takes electricity from
the source of generation (the power station) and increases
the voltage for transmission over a long distance. The
transmission substation is owned by the electricity
generator.
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3.
The National Grid (Transpower)
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Transpower is a state-owned enterprise that owns
and operates New Zealand's high-voltage transmission
lines - the national grid which spans the length of
the country. The national grid connects the transmission
substations owned by generating companies to substations.
Some large industrial users of electricity receive their
power directly from the national grid.
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4.
Substations
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Substations are points of off-take from the national
grid, where the voltage is lowered and fed to a local
lines company. When electricity gets closer to where
it will be used, its voltage must be decreased. Different
kinds of transformers at substations do this job, "stepping
down" electricity's voltage. Substations may also be
used to connect different transmission lines and raise
the voltage of electricity. Substations are linked by
transmission lines and are mostly owned by Transpower.
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5.
Local Lines Companies
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Local Lines Companies own the power lines and smaller
substations that distribute power to homes and businesses
throughout New Zealand. In the areas that Mercury Energy
provides power to, these companies include:
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Counties Power
North Power
The Lines Company
Unison
Vector
WEL Networks
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Horizon Energy
Powerco
Top Energy
UnitedNetworks
Waipa
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6.
Your Meter
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The electricity line from your local lines company
is connected to your meter, which is leased by your
electricity retailer, Mercury Energy. Your meter measures
the amount of electricity in kilowatt hours consumed
by your property.
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7.
Your Home or Business
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Wiring from the meter runs to a switch board, which
has circuit breakers and fuses for safety. The wiring
then goes from the switchboard around your property
to power points, lights and appliances.
It is Mercury Energy's policy to read your meter monthly, providing
the meter reader has access to your meter. This ensures
that your bill is based on accurate, actual usage
and
not estimated. Mercury will bill you for your electricity
supply as well as your local lines company connection
charges which cover the cost of delivering electricity
to your property.
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