Sustainable Energy NZ #15: Keeping it lean and mean – a summary of energy use.

Welcome to the fiftheenth post in the Sustainable Energy without the Hot Air – A New Zealand Perspective series. After our previous posts on hydro power, geothermal and wind (and a summary on the big three), solarbiofuelsmarine and waste energy, we’re now attempting to answer the question:

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

Remember, 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’ve been looking to replace around 55 kWh/d/p of energy currently generated by fossil fuels. Be sure to check out our treatment on roadair transport, home energy use and general consumption from the last few days.

Summary of Energy Use

Using the MacKay categories (but ignoring imported goods and energy spent overseas on air travel), our total energy use of 88kWh/d/p breaks down as shown in Fig.3:

Fig.3  NZ Energy Use (by end use)

Summarizing the data above into what energy the average person has personal control over (excludes industry, work place etc. but includes the embodied energy of our personal paraphernalia, and energy spent overseas on air travel), we get Fig.4, or 129 kWh/d/p. We used 2005 International Civil Aviation Authority and 2004 UN data on NZ passenger kilometres for the calculating the average air use by a New Zealander. [8cc3859]

Fig.4  Personal Energy Use (including imported embodied energy and energy spent overseas on air travel)

We should note that this is higher than the previous figures of 55 kWh/d/p and 88kWh/d/p because these now include all the energy contained in products we buy and when we travel overseas. In other words, this is a more comprehensive figure. For reference, McKay says that a UK citizen uses around 195 kWh/d/p, while an American uses around 250 kWh/d/p.

For anyone interested in how they might compare to Mr and Mrs Average, the important calculations are:

  1. Cars:  Get last year’s registration and calculate kilometres travelled in a year for all your cars. Divide by 365 and divide by (no of people). Multiply by 0.65 for small car, 0.85 for SUV.
  2. Planes:  Total kilometres flown in a year, per person, multiplied by 0.00145.
  3. Food:  Reduce to 10 if vegan.
  4. Home energy:  (Total annual kWh from electricity bills + non-electric heating kWh for year)/365/no of people. (Heating cost: 1 cord of firewood is about 6000kWh, 1m3 is about 1600, 50kg of gas is about 650kWh.)
Lifestyle blocks – a perfect storm for energy inefficiency?

Lifestyle blocks, especially on arable land, are a particular problem for NZ. Virtually all renewable energy sources require a lot of land which puts pressure on our current production. A lifestyle block typically turns productive farmland into pet food. Few are truly farmed and so the occupants then typically commute for work, education and entertainment. Worse still, the commuting is often in an SUV, justified because of the farming lifestyle. Paradoxically, lifestyle block owners might espouse green values, (“grow all my own vegetables”) and may even be off-grid for power. Sadly, the high energy use associated with commuting probably negates the savings in other areas. For example, a block located 25km from work could cost 45-50kWh/d for only one return trip a day compared to 11kWh/d/p saved by being off-grid.

Summary of savings

It seems possible that a saving of about 25kWh/d/p is achievable. (This comes from 15 for cars and 10 for gadgets, lights and heating – ie, not including other potential savings in energy spent overseas by New Zealanders) This is a significant dent in the 64 kWh/d/p of non-renewable energy use that we wish to eliminate, but note that half of it depends on the eventual uptake of electric vehicles which are still a while away. We should also note that reducing our consumption of ‘stuff’ (currently around 48 kWh/d/p) is a great way to reduce overall energy intake – reduce, reuse, recycle!

Further Reading:

Christian Gebbe has made a Personal Energy Calculator based on the McKay framework for those interested in a more comprehensive energy footprint analysis.

4 thoughts on “Sustainable Energy NZ #15: Keeping it lean and mean – a summary of energy use.”

  1. I was at first a bit shocked to see how much of the pie was the CO2-e embedded in our ‘stuff’. Then I thought of the energy and emissions caused in producing the laptop I am viewing Hot Topic with ( and the back-up laptop plus the two obsolete laptops in the cupboard).
    I was also a little surprised at the air travel slice of pie but I shallowly comforted myself that I had not taken an international flight since my best mate’s wedding in 2005. Then I recall that my sister made not one but TWO Europe-NZ flights this year to visit our infirm and elderly mother. And “Skin and Blister’s” flying greenhouse gas emissions should really be on the family ledger.
    BTW are we due a meta-policy wrap-up sort of post on how we get from “here” to “there” where “there” is the achievement of the desired 25kWh/d/p savings?

  2. Mr. February!

    You’re getting ahead of me! Next post we will be exploring how we can actually get from our current ~55kwh/d/p that we source from non renewables to 100% sustainable energy (as best we can do it – because as you note embodied energy in ‘stuff’ is pretty tricky to navigate).

    Stay tuned.


  3. I sometimes ask myself “What are NZ’s working economists saying about renewable energy?”
    From what economist Eric Crampton says about the latest Pure Advantage report, the answer appear to be “Nothing that useful”.
    Crampton offers us these gems.
    1) “I was somewhat surprised to see no recommendations around allowing well-regulated hydraulic fracturing technology for natural gas extraction.” Read up Caldeira and Mhyrvold, Eric!
    2) “coal is now part of our baseload generation capacity” So you missed James Hansen in 2011? Want to borrow my copy of ‘Storms of my Grandchildren’? Or listen to a Kevin Anderson podcast.
    3) “..hydro, which is banned by the environmentalists / water spirits people..” Gross misrepresentation of Forest and Birds campaign against one dam in a conservation area – Mohikinui River. And a racial slur of Maori culture too.
    4) “…the environmentalists / scenery people have banned … putting wind power there too because it would make a tiny percentage of that scenery look different…” Gross misrepresentation of parties opposed to one wind project – Project Hayes wind proposal in Central Otago.
    5) “Greens …have succeeded in getting a pile of Councils to ban it (hydraulic fracturing) within their catchments”. Eh? In terms of the RMA and Local Govt Act that is wrong.
    Does Crampton get his information from the NZCSC? From ACT’s website?
    For me reading Crampton’s ‘odd’ viewpoint has been a real wake-up call that you can’t just assume most intelligent professional people are well-informed on (or even sympathetic to) renewable energy and climate change.

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