Tag: renewable

Sustainable Energy NZ #10 – How can we achieve a big reduction in our personal and national energy consumption?

Welcome to the tenth post in the Sustainable Energy without the Hot Air – A New Zealand Perspective series. We’ll be changing gears here from our previous posts on hydro power, geothermal and wind (and a summary on the big three), solar, biofuels, marine and waste energy. From here on out we’ll be attempting to answer the question:

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

It’s a very important topic – and one prone to greenwashing and hype. Like McKay, we want to have informed discussion about the options available to us here in NZ, so we’ll be going through topic by topic and looking at energy use in each sector of our lives: transport, residential energy, the things we buy, and so on. We hope that you find it interesting and informative.

Continue reading “Sustainable Energy NZ #10 – How can we achieve a big reduction in our personal and national energy consumption?”

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.

Continue reading “Sustainable Energy NZ #9 – Here Comes the Sum – what are renewables worth?”

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:

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

Sustainable Energy New Zealand #4 – Thar’ She Blows! Wind potential in New Zealand

Welcome to the fourth post in the Sustainable Energy without the Hot Air – A New Zealand Perspective series. Today we’ll be crunching the numbers on wind 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 and geothermal. 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.

New Zealand has significant wind resources with much of the country having average wind speeds in excess of 6m/s. Even with the amount of development since the last report in 2009, we’ve only added around 0.64 kWh/day/person.

Another 1000 turbines (around 2 times the existing capacity) could deliver 4kWh/d/p while a reasonable upper limit (avoiding national parks, settlements, structures, waterways, steep slopes, low wind areas and assuming 50% willingness by landowners) has been calculated at 83kWh/d/p [cntnmby], with 32kWh/d/p available at competitive pricing. 33kWh/d/p would see windmills on 0.6% of total NZ land area, that is, if clustered, an area the size of Stewart Island.

Continue reading “Sustainable Energy New Zealand #4 – Thar’ She Blows! Wind potential in New Zealand”

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 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?

Continue reading “Sustainable energy NZ #1 – can we live on renewables only?”