Generating Electricity in New Zealand

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Section Summary

In this section, you will learn about:

NZ's electricity is created using generators which use the movement of magnets.
NZ's electricity is largely made using renewable sources.
Huntly Power Station currently uses coal and natural gas to supplement power production, particularly during peak times such as winter.

Glossary

Key terms and definitions.

term BOLD: Definition italics

New Zealand's Electricity Grid

In New Zealand, the electricity that powers phones, lights, and even some cars originates with Transpower. This company is responsible for maintaining the power lines, towers, and other infrastructure that carry electricity from generation sources, such as hydroelectric dams, wind farms, and solar farms, to the companies that distribute it to homes and businesses. This network is known as the National Grid, or simply the Grid.

Transpower's role extends beyond maintaining physical structures. It also functions as the system operator, predicting the amount of electricity needed every second of every day. Based on these predictions, Transpower instructs power generators on how much electricity to produce to keep New Zealand running smoothly.

The Grid serves as the primary route for electricity, a major power highway that spans from Kaikohe in the North Island to Tiwai Point in the South Island. Building and maintaining this grid requires constant attention and care.

New Zealand, also known as Aotearoa, is a long, thin country with a relatively small population, which presents unique challenges. The Grid must traverse two islands, mountain ranges, forests, beaches, and a deep underwater channel. Maintaining the Grid across this diverse landscape can be quite difficult.

The National Grid is built for resilience, but extreme weather, earthquakes, and even animals can cause damage, leading to interruptions in the electricity supply.

Transpower and its contractors work around the clock to keep New Zealand's National Grid operational. When someone turns on a light, Transpower ensures that electricity is available. It functions as a reliable engine, working diligently to power everyday life, from light bulbs and computers to phones and electric cars. Therefore, when a switch is flipped, it's important to remember the National Grid and the people who work to keep the lights on.

How is Electricity Generated?

Electricity generation has something to do with how electrons react to moving magnets... let's explore!

Activity: Faraday's Electromagnetic Lab (PhET)

Use the interactive below or click on this link: https://phet.colorado.edu/en/simulations/faradays-electromagnetic-lab

Click on the 2nd tab (Pickup Coil):

Move the magnet and watch the light bulb that is sitting on two loops of wire.
What happens when you move the magnet in different directions?
What happens if you move the magnet faster/slower?
What happens if you make the magnet stronger/weaker?
What happens if you make the loops of wire larger/smaller?

Click on the last tab (Generator):

Open the tap at the top to make the magnet spin. Watch the light bulb that is sitting on two loops of wier.
What happens when you make the magnet spin faster?
Which settings will make the light bulb brighter overall?

This is what an electrical grid looks like in slow motion!

This "flashing" effect (as seen in the video, in slow motion) is happening for our electricity grids all the time! But it happens so fast our eyes can't see it!

In New Zealand, our grid "flashes" 50 times a second; other parts of the world "flash" 60 times a second.

When magnets move next to metal, electrons can be forced back and forth along wires. This movement of electrons is called electricity. As the electrons move, they carry potential energy. This potential energy gets transformed into light, heat and other types of energy when the electrons move through different appliances.

How does New Zealand get its Power?

New Zealand's power generation varies significantly between its two main islands. The South Island almost entirely uses renewable energy, with a 98.3% of its electricity generated from hydroelectricity. The small remaining portion of its power needs is generated from wind energy.

In contrast, the North Island gets its energy from a range of renewable and non-renewable sources. Natural gas is the largest single contributor, accounting for 31.2% of its power. Hydroelectricity also plays a substantial role, providing 29.4% of the North Island's electricity, followed closely by geothermal energy at 22.6%. Coal contributes 7.9%, while wind power provides 6.5%. The remaining portion of the North Island's energy supply comes from bioenergy.

Hydroelectricity: This is electricity generated by harnessing the movement of water, typically through dams that create reservoirs and release water to spin turbines. It's a renewable and largely emission-free energy source.

Wind Power: This involves converting the kinetic energy of wind into electricity using wind turbines. These turbines typically have large blades that rotate when the wind blows, turning a generator. It is a renewable energy source.

Natural Gas: A fossil fuel formed from the remains of ancient plants and animals, natural gas is primarily made of methane. It is burned in power plants to heat water, producing steam that drives turbines to generate electricity. While cleaner-burning than coal, it still produces greenhouse gas emissions.

Geothermal Energy: This type of energy harnesses heat from within the Earth. Geothermal power plants typically draw hot water or steam from underground reservoirs to drive turbines and generate electricity. It is a renewable energy source.

Coal: A fossil fuel formed from compressed organic matter over millions of years, coal is burned in power plants to heat water, producing steam that drives turbines. It is a major contributor to greenhouse gas emissions and air pollution.

Bioenergy (or Biomass Energy): This involves generating electricity from organic matter, such as agricultural waste, forest residues, or dedicated energy crops. The biomass is typically burned to produce heat, which then drives turbines. It can be considered renewable if the source material is replenished sustainably, but its carbon footprint depends on the specific source and processing.

Huntly Power Station

The majority of electricity in New Zealand is made with renewable energy sources. However, several major power stations, such as Huntly Power Station, still use coal and natural gas. Huntly Power Station is the largest power station in the country by capacity, and the majority of energy created there goes to Auckland's electrical grid.

“Changes in coal use in the North Island are heavily influenced by the Huntly Power Station. This is the only coal-fired power plant in New Zealand and is important for security of electricity supply.

Electricity from the Huntly Power Station may be needed in dry years and periods of limited natural gas supply to meet our requirements for winter energy and peak demand.” (Energy in New Zealand, 2023)