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 tinyurl.com/(whatever 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, (http://tinyurl.com/deraff). The most recent data is up to the end of 2011. Important supplementary data came from various Energy Efficiency and Conservation Authority (EECA) reports (http://tinyurl.com/ydtzb5v) . 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 firstname.lastname@example.org or email@example.com.