The Blog

Behind The Bulb: The National Grid 101

Ever wondered what folks mean when they refer to the national grid? You’re not alone - it’s probably not something most of us choose to read up on in our spare time (unless you’re an electricity enthusiast, in which case - go you!).

So, who and what is this thing? Well, in New Zealand, there are three stages involved in getting power to your home or business: Generation, Transmission and Distribution. When we talk about the national grid, we’re generally referring to Transmission and Distribution - let’s take a quick look at how it all works.

Getting power from A to B

Generation is the process in which electricity is created from things like water, wind and geothermal activity.

Transmission comes next, and it consists of the monstrous big pylons and system of lines that you might have noticed running the length of New Zealand, and the very large High-Voltage Direct Current (HVDC) cable that joins the North and South Islands.

The lines connect each electricity generator with one of the 170 substations, before branching off to the smaller distribution networks. The HVDC cable is a big one, running between the Haywards Substation in Wellington and Benmore Hydro Station in Canterbury. It mainly transports power from the South Island to the North, because most of our power is generated down south. All this combined makes up the national grid, which is owned by the Crown, and run by state-owned Transpower.

Distribution is made up of the smaller power lines and power poles you see down your street. It takes power directly off the National Grid to the ICP (Installation Control Point) at each home or business. It’s at this point that electricity supply becomes the responsibility of your retailer, but before that, distribution companies (also known as lines or network companies) keep the lines in working order and make sure they have enough capacity to bring power to each customer. If you’ve signed up with a power retailer, then you’re accessing power from the national grid. So, if you’ve ever heard the term ‘going off-grid’, it means generating all your own power, or having no power at all.

Can I choose what power I use from the national grid?

Nope - it doesn’t work like that, unfortunately! Hydro and wind, two of New Zealand’s main renewable generation sources, are environmentally friendly, producing zero carbon emissions. Coal, gas and diesel generators produce the highest carbon emissions. But no matter where it’s generated, it all goes to the same place - the national grid.

What’s fed into the national grid at any one time is dependent on supply and demand factors (so, how much we’re using in relation to how much is available). But once it’s all in there, it’s blended together like a big pot of vege soup. And just like said vege soup, you can’t pick out the bits you want, like the type of generation you prefer to use.

But what if I’m with a retailer that sells me 100% renewable electricity?

It’s a common misconception that if you’ve signed up with a retailer that generates renewable electricity, you’re using the renewable stuff when you flick the switch. This simply isn’t the case.

Some retailers have a generation arm as well as a retail arm of their business, like Meridian, Mercury, Contact, Genesis and Trustpower. These companies are called gentailers (generators and retailers rolled into one), and if they talk about being 100% renewable, they’re referring to the generation arm of their business. The power you’re using is the same stuff the rest of New Zealand is using - a blend of what’s available.

That’s because renewables are less reliable than fossil fuels. While we can burn coal whenever we need to, it’s much harder to turn the wind on or top-up low hydro lake levels. So while we’re doing much better than most countries, the national grid still relies on fossil fuels for stability.

Do I have any influence over how ‘clean’ my power is?

Yip - the good news is that Kiwi electricity users can have a big impact on the electricity mix we’re using in New Zealand. As consumers, we have a lot more power and control over our electricity generation – its cleanliness, its dirtiness, and its related environmental effects – than most of us realise.

And that’s exactly why we created our Carbon Tracker tool, also known as CHOICE, which sits inside the Flick app that lets you see the real-time carbon emission levels our generators are producing, thanks to some clever information from Energy Market Services by Transpower. Knowledge is power, we reckon and CHOICE helps us all make educated, informed decisions about when is an environmentally better, or worse, time to use our electricity.

In our next Behind-The-Bulb blog we’ll take a look at the different types of generation feeding the national grid, and the impact they have upon the electricity industry’s carbon emissions. Flick yeah!