Where does our power come from?

The ability to switch on a light – something which many of us probably take for granted.

Electricity is a huge part of our lives and even a brief cut can prove disastrous, as demonstrated by the Auckland cut on Monday.

But how much do you really know about the state of the electricity sector in New Zealand?

Let’s conduct a zap around a short-circuit of New Zealand’s electricity supply and have a look at the current state of things. I’ll try not to plug any specific companies and I hope you find it en-lightening.

New Zealand’s population (estimated by stats.govt.nz as of 2pm, January 26) is 4,352,330 people.

Transpower (a state-owned enterprise) estimates that on average we use 8.12 KWh of electricity each day, which takes 30,000 litres of water to generate.

So, going by that figure, as a nation on average we consume 35,340,919.6 KWh (or 35.24 GWh) each day – requiring 1,060,227,588,000 litres of water. That’s over a trillion litres per day – 1.06 cubic kilometres’ worth, or twice the amount of water in Sydney Harbour (2 sydharbs).

There are 40 major electricity generation stations connected to the national grid, owned (mainly) by six companies, Contact Energy, Genesis Power, Meridian Energy, Mighty River Power, Todd Energy and TrustPower.

The station which produces the most electricity is the Huntly coal/gas station in Waikato, which produces about 17% of New Zealand’s power, almost twice as much as the next biggest, the Manapouri hydroelectric station in Fiordland National Park.

Most of the Manapouri station’s output is consumed by the Tiwai Point aluminium smelter near Bluff.

High voltage electricity from producers is sent through Transpower’s lines to transformers where it is converted into lower voltages for distribution to local consumers.

The power is sold to the user by power retailers, mainly Contact Energy, Empower, Energy Online, Genesis Power, Meridian Energy, Mercury Energy, Bay of Plenty Electricity, King Country Energy and TrustPower.

New Zealand’s electricity supply is watched over by the Electricity Commission, a crown entity established in 2003, which reports to the Energy Minister, Gerry Brownlee.

The commission’s primary objective, in accordance with the Electricity Act, is to “ensure that electricity is produced and delivered to all classes of consumers in an efficient, fair, reliable and environmentally sustainable manner”.

They are also responsible for promoting the conservation of electricity.

Transpower states that their national grid is the “backbone” of New Zealand’s power supply, calling it “robust and reliable”.

Lines catch on a tree, start a fire and that’s it, a massive outage. Hardly what I would call robust.

So, on the surface, it seems this was Transpower’s problem, but how did this weakness get past the commission?

As for the future of New Zealand’s power supply, our needs are always on the rise and Transpower states “significant investment in new and upgraded transmission lines will be needed”.

This is backed up by a warning from the Electricity Commission saying New Zealand is in line for more power cuts due to lack of generation by 2013. They say we need more producers “in order to maintain winter capacity margins above the security threshold”.

So, from what I understand, the message is if we don’t get more investment in this area soon, the problem won’t be in the lines, it will be in the power stations when demand outstrips supply.

Some might think nuclear power is an option. Electricity chair David Caygill argues the cost is too high and that having such a large plant would be putting too many eggs in one basket, should it suffer a problem.

The Electricity Commission is due to be replaced by the Electricity Authority if Gerry Brownlee’s Electricity Industry Bill passes into law near the end of 2010.

By the way, this blog is meant to be an overview of the situation in New Zealand. My apologies if I have anything wrong, I am not an expert, but that’s about the short of it.

I hope if there are any real experts out there, they will correct me and contribute their opinion.

I’m also really keen to hear from you if you were affected by the outage and in what way it had an impact on your day.

Last updated 09:49 27/01/2010