Exactly how electricity gets from its many sites of generation to the million or so households and businesses around NZ is a bit of a mystery to most of us. Sure, the powerlines and pylons dotted around the place are somewhat of a giveaway, but really, a good portion of us know very little about it.
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Here in NZ, we have three main stages in the production of our energy. The first step is Generation, or the various ways that we generate our electricity from things like water, wind and geothermal activity (check out our ‘Talkin’ about our Generation‘ blog for some good information).
Next up are the confusing wee beasts known as Transmission and Distribution. We don’t blame you if you switched off (see what we did there…) at the sound of those two words. They don’t exactly scream excitement. But don’t be fooled, lovely people. Because these two stages are the backbone of our electricity industry. They’re the super-highways that get electricity from Point A to Point B (or you may remember them as one of the utilities from your Monopoly board).
So, to enlighten you…
At some point in your day-to-day life, you may have heard talk of the national grid. This somewhat ambiguous name doesn’t give much away, so you’d be forgiven for imagining that the national grid consists of an enormous, walled switchboard run by a little old man, wearing spectacles and a visor, moving plugs and flicking switches and zipping around on an old library ladder. Or even a huge Battleship-esque grid with little electricity figurines on it. The national grid is pretty cool, but it’s not as cool as that – sorry guys.
What it is though, is a system of lines spread down the country between populated areas, and one very large cable that joins the North and South Islands. The lines are different sizes and can carry alternating currents, ranging between 50 kV right up to 400 kV, though most lines in NZ run at either 110 or 220 kV. They connect each generator (for example, Lake Karapiro’s hydro dam) with one of the 170 substations, and then the smaller distribution networks (which branch off into each area). The transmission network is carried by the big pylons and lines you often see throughout the countryside.
An integral part of the grid is what’s known as the HVDC cable (that’s High-Voltage Direct Current cable for you anti-acronym-ers) which connects the North Island to the South. This cable is a biggie, carrying 350 kV of electricity both ways, though it primarily transports electricity from the South Island to the North. It runs only between the Haywards Power Station in Wellington and Benmore Hydro Station in Canterbury – there are zero off-shoot lines along the way. Neat stuff.
The National Grid is owned by the Crown, and run by state-owned enterprise Transpower. They’re in charge of developing and maintaining the grid, and ensuring it can meet our growing demands.
You can think of this as the little brother of the larger transmission network. It feeds directly off the national grid, and is made up of the smaller power lines and power poles we see around our more populated areas. The role of the distribution network is to carry electricity from the bigger transmission network to individual homes and businesses. They have the job of getting the electricity to what’s known as an ICP, or Installation Control Point, at each home or business. Once it’s at that point, it then becomes the responsibility of your electricity retailer (like Flick!).
Keeping the network in reliable, working order is the job of distribution companies, or lines companies. Each region of NZ has an allocated company; for example, Wellington Electricity in Wellington, Powerco in Tauranga and Westpower on the West Coast. They’re responsible for maintaining the power lines and power poles (both above and under ground) in their area, and making sure the lines have enough capacity to cater for each customer. Not such an easy task!
Believe us, we know it’s complicated. That’s why a lot of what we do is focused on bringing transparency to this remarkable industry that touches the lives of every one of us, every day. Check out our Change, it’s choice blog to find out how you can influence Generation, Transmission and Distribution to do better by your pocket, and better by our little green country.