Tag: NZ

Sustainable Energy NZ #9 – Here Comes the Sum – what are renewables worth?

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.

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Sustainable Energy NZ #8 – The Tides They Are A-Changin’ – the marine and waste energy resource

Welcome to the eighth post in the Sustainable Energy without the Hot Air – A New Zealand Perspective series. Today we’re crunching the numbers on marine and waste incineration potential in New Zealand. 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 and biofuels. 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. 

The marine environment offers several possible renewable energy sources, notably wave and tidal energy. Wave energy systems have been studied by the Electricity Authority, and data here comes from their report [yeqtogu]. Feasible wave energy plants need wave energy greater than 20kW/m “close” (say 6km) to coast. New Zealand has 2000+ km of coast-line fulfilling these parameters, mostly on the west coast. Wave derived energies in the far south can be 60 to 80kW/m, which is impressive. That is approximately 86kWh/d/p for a 50% efficient wave generator covering half our available coastline. However, a reality check indicates that no such mechanism exists (so far wave generators have been built for survivability rather than efficiency) and many factors would constrain where wave generators could be built.

A fairly detailed analysis based on currently available technology has identified sites offering perhaps 2kWh/d/p and a maximum potential for perhaps 27kWh/d/p. While a number of prototype and early commercial plants have been deployed worldwide since 2009, this realistically still is best be described as an emerging technology with very substantial environmental and economic barriers to deployment.

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Sustainable Energy NZ #7 – Biofuel Bonanza? – NZ’s bio-energy potential

Welcome to the seventh post in the Sustainable Energy without the Hot Air – A New Zealand Perspective series. Today we’re crunching the numbers on the potential for biofuels in New Zealand. 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. Yesterday we dealt with solar (and found it was pretty big!). Note: the units are in kWh/day/person – that is, 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. 


Energy problems are just one of the significant challenges facing our civilisation so we are reluctant to consider options that affect food production or contribute further to soil degradation. However, as we transition away from liquid fuel-based transportation, biofuels could play a role in keeping us mobile.

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Sustainable Energy NZ #6 – our place in the sun – doing the math on solar power

Welcome to the sixth post in the Sustainable Energy without the Hot Air – A New Zealand Perspective series. Today we’re crunching the numbers on solar potential in New Zealand. 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 yesterday’s summary. 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, solar! We’ve got a lot of it, or do we? Our lower latitude means that New Zealand’s solar potential is certainly rather better than that of the UK and the current world leaders Germany. A roof inclined at the optimal angle in NZ gets on average 181W/m2 in Northland, 178 in Auckland, 195 in central Otago, 185 in Canterbury. (This is based on averaging all available NIWA hourly radiation data at suitable measurement sites). This is impressive compared to the UK average of 110W/m2 and 130W/m2  in Germany.

There are 4 ways to harness solar energy:

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Sustainable Energy NZ #5 – Summing up the Big Three – hydro, geothermal and wind

Welcome to the fifth post in the Sustainable Energy without the Hot Air – A New Zealand Perspective series. Today we’re summarising the numbers on wind, hydro and geothermal potential in New Zealand (and finding they’re pretty big!). 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. 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.

So, after going through the numbers for hydro, geothermal and wind, we find that we have a total realistic extra potential generation of 59.4kWh/d/p (hydro 23, geothermal 4.4, and wind 32kWh/d/p), without considering offshore wind. So, if we don’t mind parts of the country covered with windmills, multiple new hydro schemes, including all those proposed for the Clutha and Waitaki Rivers, and new geothermal schemes, we can readily get more than our required 55kWh/d/p from hydro, geothermal and wind alone.

We don’t have to say yes to every wind and hydro proposal but we have to say yes to a great many of them. And if we want power to be affordable for everyone, we have to say yes to proposals in places where it is cost-effective to generate power.

In other words, it’s a feasible possibility.

The important point to make here is that much of the energy we’ll be generating will be in different forms to those we will be replacing – i.e. we’ll be generating a lot more electricity, but moving away from energy in liquid fuels. It’s worth noting that even if we manage to find a significant resource of oil in our offshore drilling efforts, this will be sold on the international market. Also, because they’re finite won’t change the long term requirement of having to transition towards renewable energy sources.

Aside from these options, there are other possible sources of power that will become more important over time. We’ll be having a look at them in our next post.

Summary: We could meet of our energy requirements (note: not including our air travel, diesel fuel used for shipping or the embodied energy in imported products) almost exclusively on a hydropower, wind and geothermal. It would mean saying yes to schemes that are in places where it’s cost effective to generate power.

Up next: We crunch the numbers on solar for New Zealand and find it’s a pretty massive resource.