Sustainable energy NZ #1 – can we live on renewables only?

Welcome to the first post in the Sustainable Energy without the Hot Air – A New Zealand Perspective series. Today we’ll be going through the figures of our current energy use. This helps us get a baseline of consumption to aim towards, and lets us explore the difficulties in calculating per capita energy use. For the background to the work, please visit yesterday’s post here.

Before we begin, we should note the following:

We follow MacKay’s example in presenting all energy data in kWh/day/person. McKay’s motivation for this was that kilowatt hours are energy consumption units that most of us are familiar with from our monthly electricity invoices. To give you an understanding of the numbers, one 40W lightbulb consumes 40W per hour, or ~1000W hours (1kWh) a day. Most toasters are rated to 1kW, so running one of these for an hour will take 1kWh of power. A petrol car driving 100km will use, on average, 7 to 9 litres of petrol, which is the equivalent of 70-90 kWh of energy (one litre contains ~10 kWh). If interested, read McKay’s chapter on his reasoning and methodology here: [8z7lwjg]
All of the reference links (like the one above) are tinyURL codes. Eg the EECA library will be [ydtzb5v]). We’ve done this to maintain the same format as McKay. Most are hyperlinked but if not, type in the code).

The sources that we’ve used are noted at the end of this post, as well as our contact details and a link to the spreadsheet that we’ve used for all of our calculations. OK! With that housekeeping out of the way, lets get into it!

The big question that is continually asked about renewable energy is: Can NZ live with renewable energy only?

New Zealand consumer energy use (electricity and fuels) in 2011 was 88 kWh/d/p from all sources, and represents a drop of approximately 5kWh/d/p since 2007 (the numbers Phil used when he published his first paper). Some notes are required about assumptions used in deriving this figure. The “official figure” is 138kWh/d/p but this includes energy in coal and crude oil that is immediately exported, as well as all the energy losses involved in converting fossil fuel to electricity. However, these factors distort personal consumption figures and any consideration of how to replace one energy source with another.

Unfortunately, neither figure (i.e. 88 or 138) is a real indication of our total energy use, because both exclude “embodied energy” in imports such as cars and electronics, and exports in things like aluminium. The numbers also do not account fully for fuel we use in overseas air travel since only fuel sourced here is counted.

Currently 50% of the 88kWh/d/p is from oil alone, and only 32kWh/d/p is from renewable energy sources. While this represents a growth of ~3 kWh/d/p of renewables since 2007 (mainly due to wind and geothermal projects), it still leaves a big gap for improvement. The challenge is could we reduce our energy usage so as to live either on existing or expanded renewable sources alone? Costa Rica, North Korea and Indonesia manage to survive on around 30kWh/d/p from all sources but could we? Presently no developed country is even close.

Conclusion: To maintain existing energy consumption levels and reduce our dependency on fossil fuels we will have to say yes to new renewable energy development.

There is no magical efficiency fairy that can allow us to maintain anything like our current lifestyle without the development of new renewable energy sources. For example we need to find another 6kWh/d/p of renewable generation just to generate our current electricity without using coal or gas.

Fossil fuel use raises major issues with respect to impact on climate and sustainability of supply. MacKay builds a case for the western world aiming to reduce fossil fuel consumption to effectively zero by 2050, putting aside the question of whether this will be too late to avoid catastrophic consequences for many people. For New Zealand to achieve this goal we need to find another 56kWh/d/p from renewable sources to maintain our current lifestyle (again, not counting the embodied energy totals from our consumption of ‘stuff’).

However, there is one permissible use of coal which by itself would have low impact on atmospheric CO2. This is steel production, because we do not have an alternative technology for steel making – which is essential in many components widely used in housing construction etc. If we must have steel and cannot afford the emissions then CO2 capture must be achieved. If 1.25kWh/d/p of coal is used (current consumption), this reduces our energy production gap to ~55kWh/d/p.

The temptation at this point is to selectively extinguish major industrial energy users, thereby freeing up existing renewable energy. For example, why not close the aluminium smelter? The Tiwai smelter uses 3kWh/d/p producing aluminium for export, and closing this would reduce our gap to 52kWh/d/p [9lhp5ok]. However, aluminium is a very useful metal with many redeeming qualities, and can be easily recycled. Reducing our demand for aluminium would be useful but merely exporting the energy demand elsewhere is not. As we shall see, New Zealand is relatively well off for renewable energy and it could be easily argued that here is actually a good place to smelt aluminium.

So what is the potential for renewable energy in New Zealand?

Check the next post in the series, as we go through the capacity for hydroelectric power in New Zealand.


Our main data resource is the Energy Data File, available from the Ministry of Economic Development, ( The most recent data is up to the end of 2011. Important supplementary data came from various Energy Efficiency and Conservation Authority (EECA) reports ( . In addition to the Energy Data File, NIWA undertook a project called Energyscape in 2007/08 that mapped New Zealand’s energy options. Some of their findings have also been included [d82wl49]. Finally, the government has also studied the issue in some detail with numerous technical reports available from the Electricity Authority. [9cg5fp7]

Energy reporting for New Zealand is complicated by the questions of gross versus net, and by how and where energy transmission and transformation costs are accounted for. Again, we will follow MacKay‘s book usage as far as possible and do the accounting in a way that is relevant to the questions being asked. Are our numbers to be trusted? Well no – we make mistakes. If something doesn’t seem right, then please go back to the spreadsheet that we have used to make all calculations (found here: 9g5oupc), and email errors to or

32 thoughts on “Sustainable energy NZ #1 – can we live on renewables only?”

  1. I think one of the areas NZ is very weak on is its housing quality, particularly with respect to insulation and double glazing.

    Improving housing quality should be a top priority as a “no regrets” policy that improves energy efficiency and personal health

  2. However, there is one permissible use of coal which by itself would have low impact on atmospheric CO₂. This is steel production, because we do not have an alternative technology for steel making.

    As earlier reported on Hot Topic, charcoal might work for steel production.

    But let’s assume that doesn’t pan out: carbon sequestration is surely adequate to get to zero CO₂ net emissions, no? Or is that what you’re getting at with the gross vs net emissions part?

        1. The difference between Thorium energy and CCS is this:

          Thorium has the potential to provide us with virtually unlimited energy for thousands of years

          CCS is a complete and utter waste of human life and resources that has no environmental or economic worth whatsoever.

          1. Seriously, though, whatever potential thorium has, it does not have the potential to solve the crisis facing us right now, which is to stop emitting carbon over the next thirty odd years.

            CCS isn’t going to do that either, which is why the realistic alternatives are renewables – hydro, geothermal, tidal, solar and (wait for it) wind.

            Of course, given that you deny we are in a crisis, you will keep pumping your pie-in-the-sky thorium.

            1. Why do you think Thorium is “pie in the sky”?
              There was a working prototype at Oak Ridge labs in the 1950s. We went down the Uranium route for various geopolitical reasons.

              I guess you might be right in that we have dumbed down our workforce so much that there are few qualified people left to do any serious engineering work.

              The Chinese seem pretty keen though

            2. It’s certainly less science fiction than, say, fusion power.

              But as I alluded to in our last discussion of this, the R&D cycles of nuclear power development are very long and expensive. It may simply never compete with renewables on this front. At least not with people investing in energy.

              I think the nuclear industry should be the ones investing in Thorium. It should be able to burn through their waste piles, which means they get rid of that risk, and pay less for their insurance, saving money… oh, that’s right, they don’t pay for their risk.

              Perhaps these other countries will rescue this technology from the corridors of nice ideas that never made it. But last time I heard China were scaling back their nuclear ambitions drastically.

            3. I think the nuclear industry should be the ones investing in Thorium

              They are. Who else is going to do it? Oh and you are right, a lot of the modern reactors can burn through that so-called waste, which is about 95% unused uranium anyway

              Some of that “waste” is actually useful,
              e.g from Thorium

              stable rhodium and ruthenium, rare elements needed in modern electronics; technetium-99, which offers great promise as a catalyst similar to platinum; iodine-131 and cesium-137 for medical applications; strontium-90 for radioisotope power; and xenon, used in commercial products and industrial processes


            4. Thorium is pie-in-the-sky as far as being a solution to the climate problem, given how much investment would be needed to displace fossil power in the required timeframe. I don’t object to nuclear power of any form as such, although I don’t think the economics will ever make sense in NZ. But on a global scale, as a means of decarbonising in the next 20-30 years? Not a hope.
              I wrote an article in 1989 advocating a switch to nuclear power as a means of displacing fossil fuels, and maybe if the world had gone full tilt at nuclear back then we wouldn’t be in the mess we are in now. But that ship has sailed, so we need to look at the non-carbon sources that can be rapidly deployed. And we all know what that means…

    1. Interesting samv – I had missed that. Getting good airflow with charcoal is tough but NZ steel is buying, then I would say they had cracked it.

      Andy S – while I agree that cost estimates are horrendous, all elements of CCS are working in part, somewhere in the world (eg Kapuni strips CO2, CO2 is injected in for storage by Statoil, and for enhanced recovery by many companies – manufacturing their CO2! ). I think we have plenty of alternatives to CCS but too soon to right the technology off.

      1. I stand corrected that Sleipner has CCS but I remain somewhat sceptical about the widespread use of this and also I am somewhat dubious that the CO2 will stay in the underground aquifers over a long period of time

        Nevertheless, it is in the interests of Statoil to claim that it works

          1. As far as CCS is concerned, it is a function of economics and engineering feasibility.

            I know a number of UK based geologists that think there is an industry to be had pumping CO2 into depleted oil fields in the North Sea. However, if you are getting paid about 2-3 euros a tonne to get rid of CO2 then it is not even a starter

      2. By far the most effective CO2 sequestration technology might be fertilized algae blooms on the ocean. In the end this is part of the process that go the fossil carbon to where we dig it out from today. It could probably be done with the least amount of technology and energy.

    1. NZ Energy consumption dropped 5kWh/d/p from 2007 to 2012 but I doubt this attributes as an ETS effect. We have also put in lots more wind and geothermal which is inline with energy policy of moving to renewables and surely the ETS is making the cost equation for these schemes more favourable than building a new coal-powered station.

  3. CTG writes ‘…pie-in-the-sky thorium’
    India’s first large scale fast reactor should start operating within six months. It will be used to cook up thorium from their abundant monazite sands to make uranium 233; six more are due to follow.
    ‘ ….last time I heard China were scaling back their nuclear ambitions drastically.’
    China has 15 reactors at present; in three years, with the ones being built now, that will rise to 42. By that time their construction teams should be getting into the swing of things. They are also working on three different types of alternative reactor, two of which should be suited to modular construction – build them in a factory, ship them out.

  4. Short answers, a lot and plenty. Proponents claim that it should be possible to bring the price of power from a fluid fuel reactor below that from coal ; even just replacing the dozen largest coal power plants worldwide would make a sizeable dent in emissions. Note that Google a few years ago made a goal of bringing solar costs below coal ; even ignoring storage, they failed. Any scheme to replace all fossil fuels is going to be an enormous undertaking, but with largely intermittent and dispersed energy sources, I doubt it would even be possible.
    Thorium is one possible path forward, but current reactors are doing a good job of providing power without emissions, and could do a lot more. New Zealand was planning a nuclear plant in the late seventies, but they found Maui gas and Huntly coal ; now that most of those are in the atmosphere , we should reconsider it.

    1. All possibilities need to be explored – I’m a fan of the “wedges” approach – start investing now in 8 or 9 different approaches for energy generation, transport and efficiency, and as each of them expands you end up with very rapid displacement of fossil after a few years.

      The countries that already have nuclear need to keep on with those. Like I said, I don’t think the economics of nuclear will ever work in NZ, especially given the renewable resources Phil and Oliver are describing.

      But certainly thorium isn’t “the” answer.

  5. MacKay’s book available on line with nuclear section here has discussion of this. (and yes, we have plenty of nuclear). Extensive discussion at Brave New Climate blog as well.

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