Welcome to the ninth post in the Sustainable Energy without the Hot Air – A New Zealand Perspective series. Today we’re summarising the numbers on the various renewable energy options in New Zealand (and finding they’re more than sufficient!). For the background to the work please our introductory post here. Also check out our earlier posts on the potential of hydro power, geothermal and wind, and the summary on the big three. More recently we’ve dealt with solar, biofuels, marine and waste energy. Note: 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.
So we’ve gone through the various renewable energy options over the last week or so. So where does this leave us for increased generation potential among renewable options? The affordable, mature technologies are hydro, geothermal, wind, waste gas, solar heating and biofuel. Large-scale solar and marine technologies are really promising options for the future but cannot be realistically considered now.
Fig.1 summarises the current and potential future amount of energy generated in NZ from the various renewable sources discussed above. The numbers used are conservative, allocating only relatively small areas to solar in the distant future. New Zealand is energy-rich but every option using renewable sources will have its own problems.
- Current consumer energy use is 88kWh/d/p, of which 32 is from renewable sources. 50% of energy use is from petroleum.
- These numbers are for current population (4.4 million). If the population grows to 5 million by 2050 as projected, then the numbers should be scaled back by 9/10.
- The estimate for biofuel is based on minimal encroachment onto food producing land. Using all arable land for biofuel instead would deliver 43kWh/d/p.
And finally a word about Nuclear Energy
Nuclear energy is not a renewable resource but MacKay argues that it is possibly a sustainable energy source, and certainly it could be an alternative to lots of windmills and dams. The issues associated with nuclear energy are dealt with at length in MacKay’s book and don’t need further repetition here. For a New Zealand perspective, we would note that we don’t have any commercial uranium deposits, we are prone to earthquakes and tsunamis with similar risks to Fukushima and that commercial technologies for truly sustainable nuclear energy production are still in the future. For the moment, New Zealand has other renewable options.
And that ends this first part of the series. Next up, we’ll be looking at what options exist for reducing our energy footprint, and then looking at what a realistic plan might be for New Zealand. Check in for the next post — coming soon.
Oliver and Phil
We’ve tried to include supplementary reading during these posts, and this one is no different. UCSD professor Tom Murphy, author of the excellent site Do The Math, has done a similar set of analysis (mainly concentrating on the USA) and come out with the following Alternative Energy Matrix. It is well worth a read because the global scenario is a bit different from our own – the majority of the world’s population don’t live on a island with a very temperate climate, low population density and plenty of energy options.