Where's my electricity from and how does it get to my home?

You flick a switch and your living room light turns on. Simple, right?

Well, follow the flow of electricity back to its source and along the way you’ll find a complex world of turbines, generators, cables and power grids working seamlessly to deliver the energy needed to power modern life.

Curious about where your power actually comes from? Read on for a quick primer on where New Zealand gets its electricity from and the infrastructure involved in getting it to your house.

Where does New Zealand get its electricity from?

New Zealand gets its electricity from a variety of sources, most of which are renewable. In fact, about 85 percent of electricity generated in New Zealand in 2016 was renewable (the highest it’s been in 25 years), according to research from the Ministry of Business, Innovation and Employment. This puts New Zealand among the top five countries in the world in terms of the proportion of renewable energy generated. The government wants to build on these figures and reach 90 percent renewable energy generation by 2025.

Reducing our dependence on non-renewables helps keeps emissions low and ensures we have a secure supply of energy in the years ahead as finite resources such as fossil fuels become more scarce.

So, a huge chunk of New Zealand’s electricity comes from renewable resources, but what exactly do these resources look like?

Hydro

Hydropower is the dominant force in New Zealand’s electricity generation industry and accounts for about 57 percent of the power generated in the country. Hydro generation essentially involves using gravity to push water through enormous turbines and converting that energy into electricity. Big hydro stations, such as those found in Benmore and Manapōuri, allow for electricity to be generated on demand, but most hydro schemes don’t have the same level of water storage capacity. The supply of water at most hydro stations naturally fluctuates, meaning the amount of electricity produced isn’t always 100 percent predictable.

Geothermal

Because New Zealand is located on the boundary between two tectonic plates, the hot mantle beneath the Earth’s surface is relatively accessible. This means we’re one of the few countries in the world that is able to harness the potential of geothermal energy and turn it into electricity. Geothermal power stations direct geothermal fluid from deep beneath the earth’s surface to a centralised plant, where the fluid pushes through turbines and is converted into electricity. Most of our geothermal plants are located in the Taupo Volcanic Zone. Geothermal energy accounts for about 15 percent of our electricity generation.

Wind

Wind farms have rapidly grown in popularity over the last couple of decades. We now have 19 wind farms producing about 5 percent of all electricity generated in Aotearoa, according to the Energy Efficiency and Conservation Authority. Installed in blustery regions, wind farms use the force of the wind to turn turbine blades and convert that energy into electricity. The amount of electricity generated depends on how fast the wind is blowing. Given that wind farms don’t produce greenhouse gas emissions and are easy to install and remove, it’s likely that wind energy will play an even bigger role in New Zealand’s electricity industry in the years ahead.

Cogeneration

A relatively recent innovation, cogeneration works by essentially recycling the heat produced in an industrial process and turning it into electricity. In the process of making steel, for example, a lot of gas is produced as a byproduct. Usually, this gas would just go to waste, but a cogeneration scheme allows industrial plants to recover the gas, burn it, and use the resulting heat to produce steam, which is then used to drive a turbine and generator. Cogeneration accounts for about 3 percent of the electricity generated in New Zealand.

Thermal

The remaining 20 percent or so of New Zealand’s electricity comes from thermal plants that rely on coal, diesel or gas to generate electricity. While these aren’t the most environmentally friendly options, they are stable and predictable, which makes them useful when it comes to accurately meeting supply and demand. Thermal generation can be used to reliably generate electricity when the availability of other resources may be low due to the season or natural weather cycles.

How does the electricity get to my house?

Okay, so now we have a pretty good understanding of where our electricity comes from. But how exactly does it get to your house? Generally speaking, the process can be broken down into four key steps:

1. Generation

To deliver power to your house, the electricity first has to be generated! There are five main companies that are responsible for generating electricity in Aotearoa. These companies turn natural resources into electricity using one of the generation methods described above (hydro, geothermal, wind, cogeneration or thermal).

2. Wholesale market

The electricity generated in step one is then sold on the wholesale market, where electricity retailers can purchase it. Prices can vary substantially throughout the day according to current supply and demand.

3. Transmission

Although the majority of New Zealand’s electricity is generated in the South Island, most of the demand is in the North Island, and Auckland in particular. To get the electricity where it needs to go, Transpower transmits the electricity via the national grid to local grids. In some cases, large sites are able to skip this step and connect directly to the national grid.

4. Distribution

Once the electricity has entered the local grid, the next challenge lies in distributing the electricity. Distributors make use of a local distribution network comprised of underground cables and overhead wires to get the electricity into your home.

Not quite as simple as flicking a light switch

It’s easy to take electricity for granted, but as you can see there’s a lot of complex infrastructure that goes into providing your home with the electricity you need in your day to day life!

Here at Grey Power Electricity, we’re proud to play a small role in providing electricity to Kiwis across the country. If you like the sound of low up-front prices, no contracts and transparent billing, give us a call today.