Ngatamariki Power Station facts for kids

The Ngatamariki Power Station is a special kind of power plant in New Zealand. It uses heat from deep inside the Earth to make electricity. This type of energy is called geothermal power. The station started working in September 2013 and is run by a company called Mercury Energy.

You can find the Ngatamariki Power Station about 17 kilometers (about 10.5 miles) northeast of a town called Taupo. Building this power station cost around NZ$475 million.

How Does Geothermal Power Work?

Geothermal energy comes from the Earth's natural heat. Deep underground, there are hot rocks and water. This heat is created by the slow decay of radioactive materials in the Earth's core.

Tapping into Earth's Heat

Engineers drill deep wells into the ground to reach these hot areas. The hot water and steam from these wells are then brought to the surface. At the Ngatamariki station, they use a special method called a "binary plant."

What is a Binary Plant?

In a binary plant, the hot geothermal water doesn't directly touch the turbines that make electricity. Instead, it heats another liquid, called a "working fluid," which has a much lower boiling point than water. When this working fluid gets hot, it turns into vapor. This vapor then spins a turbine, which is connected to a generator to create electricity. After spinning the turbine, the vapor cools down and turns back into a liquid, ready to be heated again. This process is very efficient and clean.

Building the Power Station

Before the power station could be built, scientists and engineers had to explore the area. They started drilling test wells way back in 1985 and 1986. These first wells, named NM1 to NM4, went very deep into the Earth. One well, NM4, went almost 2,400 meters (about 7,874 feet) deep! It was the first time a pluton (a large body of cooled magma) was found at that depth in New Zealand.

Later, in 2008 and 2009, more wells were drilled even deeper, some reaching over 3,000 meters (about 9,842 feet). This exploration helped them understand how much heat and steam was available underground.

Construction Begins

After getting permission in May 2010, construction on the Ngatamariki Power Station began in July 2011. The main equipment for the power station, including the binary plant system, was supplied by a company called Ormat.

The power station officially started producing electricity in September 2013. It can generate 82 megawatts (MW) of power, which is enough to power many homes and businesses. There are also plans to increase its capacity to 110 MW in the future.

Connecting to the Grid

Once the electricity is made at Ngatamariki, it needs to get to homes and businesses. A special 220,000-volt power line connects Ngatamariki to another power station nearby, the Nga Awa Purua Power Station. From there, the electricity from both stations is sent into Transpower's national grid. The national grid is like a huge network of power lines that delivers electricity all over New Zealand.

Wells at Ngatamariki

The Ngatamariki Geothermal site has 7 main geothermal wells. Three of these wells are "production" wells, which bring the hot water and steam up from underground. The other four are "re-injection" wells. These wells put the cooled water back into the Earth. This helps to keep the geothermal resource healthy and sustainable for a long time.

In addition to these main wells, there are 21 smaller wells called "sentinel" and "monitoring" wells. These wells are used to keep an eye on the geothermal field, making sure everything is working correctly and that the resource is being managed well.