Earth’s inside for better air 2

In our 2012 article Earth’s inside for better air, we explained that New Zealand is a country where geothermal energy is widely developed. We mentioned Wairakei power plant, the second commercial geothermal plant opened in the world. This was in 1956. New Zealand was world leading! Well, being in New Zealand again, we decided to go to the plant…

HAPPY TO BE THERE, READY TO DO MORE

“We are committed to protect the quality and quantity of water to New Zealanders,” Rosanne says. We had the chance to meet Rosanne Jollands, Community Relations Manager and Genelle Slack, Senior Environmental Advisor, at the power plant. The installation has a capacity of 156MW. It is operated by the company Contact, employing 120 people on site.

Genelle on the left and Rosanne on the right.

Geothermal plants exploit natural hot underground waters to generate electricity. They release very few quantities of greenhouse gases compared to coal or gas power plant. Fortunately New Zealand has decided to use its strong geothermal potential. Genelle says: “Currently 82% of the energy comes from renewable sources. It is a very good figure. The objective is to reach 90% by 2020.” New Zealand runs a national carbon emission trade market where “the price of one ton of CO2 is currently around 18 NZD. Such a trade market aims to reduce the country’s emissions year after year by progressively increasing the price of an emitted ton.”

 This small chart describes how a geothermal plant works. ©Mercury

We used a nice plug-in hybrid
car to visit the plant!

Genelle adds: “Still our power plant generates greenhouse gases. This is why we invest in projects to reduce further the carbon footprint, and then pay less within the emission trade market. One ongoing project deals with two gases produced during the operations, carbon dioxide and methane. Today they are released to the atmosphere. We want to inject them into to the cold water which is going back to the ground. Such an additional process is viable only thanks to the carbon price.” The experts working on the international negotiations on climate change agree that a major next step is the definition of a carbon price, at the international level.

GENERATING ELECTRICITY, BUT NOT ONLY

“Earlier this year the World Geothermal Conference was held in Melbourne,” Rosanne explains. “Right after the Conference, Contact received many visitors here at Wairakei plant. All these visitors wanted to know more about how we operate here.”

A prawn farm, right outside the power plant.

Rosanne adds: “We do not only produce electricity here, the extracted hot water also goes out to few places nearby. One of them is a prawn farm; another one is hot pools!” Direct use of geothermal waters can supply heat for industrial processes. For instance, in Kawerau, northern New Zealand, the geothermal hot water is directly used by a paper mill. In Iceland, Hellisheidi plant is one of the several plants of the island; it provides 300MW of power but also hot water to the Capital city Reykjavik. Likewise, in numerous districts around the world, the extracted water is used to heat buildings. Earlier this year, we could visit the ecodistrict Fort d’Issy, in France, where 1500 modern apartments are heated by a geothermal installation. Philippines and Italy are other world leaders in geothermal energy. Let’s follow them!

Hellisheidi in Iceland, and the ecodistrict Fort d’Issy (©On Power/ ©Ville d'Issy-les-Moulineaux).

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In 2013 New Zealand generated 7,6 tons of CO2 per capita, way lower than its neighbor Australia, who produced 16.3 tons but a little bit more than France with 5,1 tons which is the same figure as the world average. The country who emitted the most in 2013 was Qatar with 40.5 tons per capita. More from the World Bank database here.

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