Sustainable Energy NZ #10 – How can we achieve a big reduction in our personal and national energy consumption?


Welcome to the tenth post in the Sustainable Energy without the Hot Air – A New Zealand Perspective series. We’ll be changing gears here from our previous posts on hydro power, geothermal and wind (and a summary on the big three), solar, biofuelsmarine and waste energy. From here on out we’ll be attempting to answer the question:

How can we achieve a BIG reduction in our personal and national energy consumption?

It’s a very important topic – and one prone to greenwashing and hype. Like McKay, we want to have informed discussion about the options available to us here in NZ, so we’ll be going through topic by topic and looking at energy use in each sector of our lives: transport, residential energy, the things we buy, and so on. We hope that you find it interesting and informative.

A few notes before we begin: as before, the units are in kWh/day/person – ie. if you ran a 40W lightbulb for 24 hours, it’d take ~1 kWh over the space of a day. We then divide it by person to give you a sense of the scale of the resource proportionate to the size of the population. Be sure to check out the methodology. For reference – we’re looking to replace around 55 kWh/d/p of energy currently generated by fossil fuels.

If we don’t like the environmental and other consequences of the generation options discussed thus far, what are the possibilities of actually reducing our energy requirements as a realistic approach to limiting the impacts of our energy use? In the coming years when dramatic CO2 reductions are necessary and required under international agreements, it may be easier if we just use less power. Let us therefore examine what energy efficiencies we can realistically expect to achieve.

To understand the effect of various efficiencies, we need to know where the energy is being spent at the moment. MacKay looked at the energy use of a “moderately affluent” adult UK resident, as a world citizen. For our purposes though, we will look at the energy use of the average New Zealander. That is, we will divide consumption by total population – adult, child and baby. So for a first estimate, we get a sector table from the Energy Data File of:








Wood, Pulp, Paper Processing


Other Industry






Aviation (fuelled in NZ)


Other commercial Transport


Retail Fuel




Fig.2  NZ Energy Use (by Sector)

Note: the small discrepancy in numbers (88 kWh/d/p mentioned elsewhere in this document vs. 90.8 kWh/d/p above) are from challenges in accounting for various sectors. It’s in the ballpark however, so not a biggie.

So, now that we have a sense of the breakdown of energy use, we’re going to break these numbers into MacKay-like categories over the next few days. We’ll start with transport/cars tomorrow. In the end, we’ll hopefully have a good sense of the amount of energy an ‘average’ Kiwi uses and where it goes. Hope to see you soon!


Oliver and Phil

Recommended Reading

Personal energy savings is where Tom Murphy’s Do the Math blog really comes into its own. I’ll be pointing out the relevant ones as we go along. His post on energy cubes is a great place to start.

Saul Griffiths, the crazy Australian genius, has a great body of work on his own personal energy consumption. He also has a great Tedtalk where he advocates the development of flying foxes and rollercoasters as forms of public transport on the basis that they are some of the most energy efficient means of transportation…

4 thoughts on “Sustainable Energy NZ #10 – How can we achieve a big reduction in our personal and national energy consumption?”

  1. At a personal level, to reduce electrical consumption, and save cost, I bought an electric usage meter. Understanding what uses the power is a good start. By switching groups of appliances off at the plug I have reduced the standing wattage of the house fro 120 watts down to 35 watts. The equivalent of burning a 100 watt bulb for a year. It may not sound like much but a meter exposes where waste occurs. Moving into the middle of town has cut my fuel use in half which is also a big saving.
    But then I flew to the UK and back.

    1. Ha! Yes. We’ll be going over the energy intensity of flight in a future post but dare I say, most any savings we make at home are lost when a kiwi flys anywhere outside of the country. Our geographic isolation doesn’t help us in this regard.

      Energy tracking is a great exercise. Tom Murphy’s work is great – he uses something called the Energy Detective which I’m aware is gaining popularity in NZ. Tracks energy use at the wall – killing phantoms along the way. Thanks for your comments.


  2. Assuming discussion is not closed on previous subjects, I want to focus a little closer on biomass. I think it got light coverage but it can be a much bigger player in the NZ energy mix. I am pushing a barrow load of biochar here but bear with me…

    Pyrolysis is a ancient but rapidly evolving pathway for biomass distillation into energy and environmental service products (the most interesting component being biochar for carbon sequestration and agriculture/soil services… but that’s another story). New & very efficient technologies are rushing our way… a prime example is Cool Planet ( with carbon negative fuel claims based on biochar bi-production. They have major backers & an ambitious roll out plan.

    If biomass processing tech like this gets a foothold, it may change our energy distribution structure, based around forestry and other coppice crop locations. Distributed energy hubs.

  3. This would be better discussed under the correct chapter. Biofuel is a form of solar energy. Whatever downstream processing of the biomass, you have to live within the photosynthetic limit for energy conversion per m2. I highly recommend MacKay’s chapter on the limits. We have downplayed biofuels to some extent because the world also needs food and competition for arable land is undesirable. However, the possibilities for woody biofuels on marginable lands are something that does have promise.

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