New Zealand's Hot Spots

At any turn in the road, you see steaming fields and hills

 The path from Whakatane and White Island to Taupo follows the surface line of the collision of the Pacific and Australian plates under the North Island.  Volcanoes, both active and dormant, dot the countryside for the 100 km drive.  Route 5 winds in between mountains, dips in the valleys and becomes the Thermal Highway once you pass Rotorua.  Evidence of geothermal activity is abundant.  Steam rises from the hillsides, flower beds hiss, and roadway drains gurgle.            Upon arriving in Kinloch, a town on Lake Taupo, I was greeted by Elizabeth and Paul, along with Saxon their nationally ranked German shepherd and Bridgette, the cat.  A warm welcome had me realizing that once again, I had picked great accommodations with wonderful people.  Elizabeth just happens to be a geothermal expert as she worked for the energy company for 20 years and she graciously offered to take me on a tour of the geothermal area.           New Zealand produces about 9% of their total power from geothermal plants currently.  They are increasing the total number of plants and within a couple of year will have the capacity to produce up to 15% of their energy needs.  They are heavily reliant on hydro power with their many rivers.  They do NOT use nuclear power as it is banned in NZ.         The Wairakei Power Station, which is a geothermal power station near the Wairakei Geothermal Field.  Wairakei lies in the Taupo Volcanic Zone. The power station was built in 1958, the first of its type (wet steam) in the world, and it is currently owned and operated by Contact Energy. A binary cycle power plant was constructed in 2005 to use lower-temperature steam that had already gone through the main plant. This increased the total capacity of the power station.   

Centrifuge to separate moisture from steam

  When harvesting geothermal energy, you can harvest wet steam or dry steam.  Since Wairakei harvests wet steam, the process to make energy is much more complicated as the pipes can only carry dry steam to the plant.  Any moisture in the steam can cause the turbines to pit since the steam is carried at such a high rate of speed. 

Pipes are not attached to support to allow for expansion and contraction due to changes of outside temperatures

 Therefore, the pipes are built with safety valves and bends to extract any moisture that could have entered the system through condensation due to temperature changes on the outside of the pipes.  One question I had was why the steam did not cool as it was traveling 2.3 to 5.0 kilometers and the answer is that it moves too fast to cool down.    

Drilling additional wells

  When the water is extracted from the geothermal field, it is over 400 degrees but is not boiling due to the extreme pressure it is under.   It is pumped into a centrifuge tank that spins the water to the bottom and the dry steam rises to the top to be siphoned off and piped to the plant.             

Power Station



  
Once the steam reaches the plant, it boils water that is used to spin the turbines to make energy.  The steam is then reused but since the temperature has been lowered greatly, it is used to boil a chemical that has a lower boiling point so that the energy is maxed out.        The water that is pumped out of the ground is full of minerals and rock so it has to be processed before it can be returned back into the ground, this is called re-injection.  Before using this process, the removal of the geothermal waters without replacing them was causing an imbalance in the underground system.  

Water is diverted back to river 3 times a day, after cooling to keep ecosystem in tack

 The processing of the water allows the super-heated water to travel down gullies that performs two processes, cooling and the minerals and rock settle down on the concrete surface.  The water alternates between two culverts so that the minerals can be scraped off due to huge amounts of buildup.   

Above ground pipes very visible everywhere with warning signs that they dangerous and will burn

 If you would like to read more about the Wairakei Geothermal Plant, here is a link to their site. http://www.nzgeothermal.org.nz/index.html        


A visit to the Volcanic Center was very educational, along with
sitting in the earthquake simulator, I know I do NOT want to experience one in real life.

Walked through "Craters of the Moon", a very active geothermal field with sites to see.

Craters of the Moon, so appropriately named

Staying on the walkway is a good idea!

Boiling mud pots

Some plants like the hostile environment



From the look out at the top of the hill