CEL 11017 Geothermal Bro FA v4 - Contact Energy

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CEL 11017 Geothermal Bro FA v4 - Contact Energy Powered By Docstoc

                                                    WAIRAKEI POWER STATION


                                                    OHAAKI POWER STATION

As New Zealand grows, so too does our demand for a strong, secure supply of
electricity. However, New Zealand increasingly needs more electricity generation
which is both reliable and renewable. This can be a difficult combination to
achieve. Most of New Zealand’s electricity is generated through large hydro
power stations and, increasingly, wind farms are also generating electricity.
Geothermal electricity – using the earth’s heat to generate power – is New Zealand’s
most reliable form of renewable energy, providing valuable baseload power,
regardless of the weather.

POWER FROM THE EARTH                                                                                                  Central North Island

                                                                              V ER

                                                        Poihipi Road                    Ohaaki
                                                            LAKE TAUPO


Many people might be surprised to know that the most reliable form of renewable electricity generation is, in areas like Taupo, literally right under
our feet.      New Zealand has been a world leader in the development of geothermal electricity generation, and Contact Energy is New Zealand’s
largest producer of geothermal electricity.      Contact Energy’s geothermal generation provides New Zealand with around five per cent of total
electricity demand. Geothermal is unique in the renewable energy world in that it provides baseload electricity that is ‘always on’ or can be switched
on when needed.        Contact also supplies direct geothermal heat to a number of businesses, including the Taupo Native Plant Nursery and Taupo
Prawn Farm. Contact has constructed a direct heat project that provides the Tenon Wood Processing Plant with up to 20MW of geothermal heat
for its wood-drying kilns.
CO N T A CT E N E RG Y                              T A U P O G E N E RA T IO N

                170°E    175°E   180°E
 35°S                                               New Zealand’s Taupo volcanic zone features some of
                                                    the world’s most spectacular geothermal areas, attracting
                                                    tourists and providing valuable baseload power.
        Tasman Sea

                             Pacific Ocean


                                                    Seven per cent of New Zealand’s total electricity is
                                                    generated using geothermal heat, with the potential
                                                    for further development of the geothermal resource.


                                                    The second geothermal power station in the world,
                                                    Contact’s Wairakei Power Station has become an
                                                    icon of New Zealand’s electricity system.


                                                    Contact’s Poihipi Road Power Station has capacity to
                                                    produce 55 megawatts (MW) of renewable electricity.


                                                    Another geothermal plant, Contact’s Ohaaki
                                                    Power Station features a distinctive 105-metre
                                                    high cooling tower.
How geothermal electricity works
In the Taupo region, New Zealand is fortunate to have one of the world’s most active and
spectacular geothermal regions. Heat from below the earth has made the region famous for
its geysers, hot pools and volcanoes, and for the innovative way that geothermal heat is
converted to electricity.
Under the surface, the planet is boiling and bubbling with energy and intense heat. The word
geothermal literally means ‘earth heat’.
When hot fluid from deep underground is discharged from a geothermal well, it comes out
either as pure steam or as a mixture of water and steam. It is the force of the steam, piped
at great speed to the power station, that is used to turn the turbines that generate electricity.
The steam can then be condensed back into geothermal water and reinjected into the ground
or discharged into particular waterways.

                                       S E PAR AT I ON P LAN T       TURBI N E      GE N E R ATO R

H OT G EOT H E R M A L   S E PAR ATE D G EOTH E RMAL                       CO OLI N G
                                                                 P UM P                   CON D E NSE R   R I VER
FLUI D                   WATE R R E I N JE C T I ON                        WATE R

The geothermal steam and water, which is removed from the ground in the process of
producing electricity, is naturally replaced through further underground inflows to the
geothermal system.
            C ONTAC T ENER GY                                        T A U P O G EN ERA T IO N   P A G E 3 /4

                                                                                                                G E O T H E R M A L G E N E R AT I O N

The legend of geothermal
Ancient Maori legend says that Ngatoroirangi, the great navigator of the Te Arawa
waka (canoe), is responsible for creating the unique geothermal features of the
central plateau region.
When exploring the region, Ngatoroirangi ascended the great volcano Tongariro to
get a commanding view of the surrounding area. His objective was to claim these
vast lands for his people. With some difficulty, his party reached the summit.
They became trapped on the peak by bitter alpine conditions, facing death by cold.
Ngatoroirangi cried aloud to his ancestral spirits to send his party fire, and sacrificed
his personal slave, Ngauruhoe, as an offering to the gods.
At Ngatoroirangi’s ancestral homeland of Hawaiki, his sisters Kuiwai and Haungaroa
sensed his call for help. They dispatched two Taniwha called Pupu and Te Hoata.
The Taniwha travelled swiftly underground and surfaced firstly at Whakari (White
Island), before heading south in the direction of Ngatoroirangi and his trapped party.
Along this path, the Taniwha surfaced many times to gain their bearings, bringing
geothermal features to the land where they emerged. This is why thermal features
are said to occur at Whakari, Kawerau, Rotoma, Rotoiti, Tarawera, Rotorua, Waimangu,
Waiotapu, Ohaaki, Orakei-Korako, Wairakei, Taupo and Tokaanu.
Eventually, the powerful Taniwha burst forth from the earth as fiery lava and a
volcano was born at this place. Ngatoroirangi and his trapped party were revived
by the volcanic heat and were saved. The body of Ngauruhoe was interned to the
newly formed volcanic crater, which still bears his name today.
The Ngati Tuwharetoa iwi of the Taupo district are the descendants of Ngatoroirangi.
Their relationship with the region’s geothermal taonga has evolved from centuries
of interaction and study, the essence of which is embodied in tradition and legend.
The climate of the central plateau is harsh. The region’s geothermal heat is a valuable
and important asset, which has been widely used for activities such as cooking for
Tangata whenua continue to hold the geothermal taonga in high regard.

              W A I R A K E I P O W E R S TAT I O N
C ONTAC T ENER GY                                        T A U P O G EN ERA T IO N                                              P A G E 5 /6

                      Wairakei – the world’s second geothermal power station,
                                                 and the first for New Zealand.

                                                                                                                                  EXPANSION LOOPS AT THE WAIRAKEI
                                                                                                                                  GEOTHERMAL PLANT.

                                                     Binary process
Commissioned in 1958 as the first geothermal plant
                                                     E LE C TR I C I TY       G E NE R ATO R       VAP O UR       CO ND E NSE R         T U RB I NE     WO RK I NG FLU I D     FLU I D P UM P
of its kind anywhere in the world, Wairakei has
become an iconic symbol of New Zealand’s
electricity generation system.

Having provided New Zealand with reliable
and renewable electricity for around 50 years,
Wairakei also boasts some of the very latest
geothermal generation technology.

In 2005, Contact opened a 16MW binary plant on
the Wairakei site – enough new generation to
increase Wairakei’s total output by 10 per cent,
or enough additional electricity to power another
15,000 homes. The binary plant captures heat that
is not used by the main Wairakei Power Station
and converts it into electricity, without drawing
any additional steam or fluid from the steamfield.

The Wairakei Power Station harnesses the power
of 1,500 tonnes of steam and 3,500 tonnes of
geothermal water per hour, allowing the generation
of enough renewable electricity to power around
150,000 homes.

Geothermal water used in the Wairakei plant is
discharged into the Waikato River and reinjected     H OT G EOT H E R M A L       SE PAR AT I ON     G EOT HE R MA L ST E AM       WO RK I NG FLU I D   CO O LE D GEOT HE RM A L   GRO U ND
back into the edges of the steamfield.                 STE AM / BR I NE               P LAN T          FO R GE N E R AT I O N       VA P O U R I SE R            BRINE              LE VE L


    Commissioning date:      1958                    Installed capacity:                181MW (including                               Depth of wells:              Average of
                                                                                        16MW binary plant)                                                          660 metres
    Average annual
    energy generated:        1,365GWh                Number of wells:                   55 production wells
                                                                                        6 reinjection wells
                                                                                        50 monitoring wells

          P O I H I P I R O A D P O W E R S TAT I O N
C ONTAC T ENER GY                               T A U P O G EN ERA T IO N                           P A G E 7 /8

                        Contact’s geothermal power station at Poihipi Road is an
                          efficient plant, converting 60 per cent of the energy in
                                                geothermal steam into electricity.

                                                                                                      CONTACT’S POIHIPI ROAD GEOTHERMAL POWER
                                                                                                      STATION, TO THE NORTH OF THE TAUPO TOWNSHIP.

Poihipi Road
  Statistics                                   Contact’s Poihipi Road Power Station was
                                               commissioned in 1996 and was purchased by
                                               Contact in January 2000. Poihipi Road is located
  Commissioning date:     1996
                                               on the south-western edge of the Wairakei
  Average annual                               steamfield and is supplied with steam from the
  energy generated:       207GWh               Wairakei geothermal system. The Poihipi Road
                                               Power Station has the potential to generate around
  Installed capacity:     55MW
                                               55MW of electricity, enough to power 50,000
  Number of wells:        4 production wells   homes, and reinjects all geothermal water back
                          1 reinjection well   into the edges of the steamfield.

C ONTAC T ENER GY                                 T A U P O G EN ERA T IO N                             P A G E 9 /1 0

                         Ohaaki’s eye-catching cooling tower removes the need for
                                        a cooling pond the size of 200 rugby fields.

                                                                                                         THE ENERGY CONTROL ROOM IS THE CENTRE OF
                                                                                                         ACTIVITY FOR OPERATION OF THE POWER STATION.

   Statistics                                    The Ohaaki Power Station was commissioned in
                                                 1989, and the field is located approximately 30 km
                                                 north-east of Taupo. Production wells at Ohaaki are,
   Commissioning date: 1989
                                                 on average, 1.2 km deep and reach water at
   Generation capacity: 105MW                    temperatures up to 280°C.

   Installed capacity:     104MW                 The most distinctive feature at Ohaaki is the
                                                 105-metre high cooling tower. Using natural
   Number of wells:        16 production wells   convection, the tower cools the water used to
                           6 reinjection wells
                                                 condense the steam as it exits the power turbines.
                           25 monitoring wells
                                                 The Ohaaki geothermal plant has capacity to provide
   Depth of wells:         Average of 1,200      104MW, enough to power 100,000 homes. However,
                                                 recently Ohaaki has been operating at less than
                                                 capacity due to a shortage of geothermal steam.