Tag: sustainability

Sustainable Energy NZ #3 – When having a Hot Earth is Desirable – Crunching the numbers on Geothermal.

This is the third post in the Sustainable Energy without the Hot Air – A New Zealand Perspective series. Today we’ll be crunching the numbers on geothermal potential in New Zealand. For the background to the work and an explanation of the methodology, please visit this post. Also check out the last post on the potential of hydro power.

Unlike the UK, New Zealand has significant geothermal resources which currently contribute to national energy requirements. Geothermal energy has the advantage of being always available at full capacity, and unaffected by weather. Currently about 5.2kWh/d/p is available (3.6kWh/d/p of electricity is produced plus 1.6kWh/d/p in direct heating) but it is estimated that there is potential for a total of 12kWh/d/p at an admittedly higher price than gas generated electricity [dbpz7n]. Environmental and regulatory constraints further limit development. The Electricity Authority foresees generation rising by a further 4.4kWh/d/p by 2025 [9v5c9my] but little growth beyond that. Geothermal energy is low quality, producing lots of hot water for disposal. Ideally, better use of this hot water in co-located industry would improve overall efficiency.

Summary: There’s definitely potential here – but remember that even if we built every geothermal plant in the pipeline it’ll only ever make up about 8-9% of our overall energy supply.

Further Reading:

UCSD Professor Tom Murphy of Do The Math does the numbers on global geothermal potential.  

Sustainable Energy NZ #2 – How much dam energy is there anyway?!

Welcome to the second post in the Sustainable Energy without the Hot Air – A New Zealand Perspective series. Today we’ll be crunching the numbers on hydroelectricity potential in New Zealand. For the background to the work and an explanation of the methodology, please visit our last post here. Remember that we are looking for around 55 kWh/d/p from renewable sources to replace what we currently use today. So, with that, today’s post!:

At the moment, ~15kWh/d/p of New Zealand’s energy comes from hydroelectric generation. How much more is feasible? For the United Kingdom, MacKay simply does back-of-the-envelope calculations, but because of widespread hydro-electrical use in New Zealand, there are reports that allow us to make a more complete assessment of hydroelectric potential. [8k8vf25] and [9nvw27h]. Firstly, I discount any scheme that would be in a National park, or protected by a strong Water Conservation Order (e.g. Motu), or extremely remote. Some 34 schemes of >20MW capacity have already been identified as economically and technically feasible (e.g. Mokihinui River). These deliver a potential of 10kWh/d/p. on top of the 15.4kWh/d/p already commissioned. 26% of that is from North Bank Tunnel project in the Lower Waitaki and a further 22% comes from four possible schemes on the Clutha River.

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A Sustainable Energy Future For NZ (without the hot air) – An Update

This is a guest post by Phil Scadden and Oliver Bruce (bios at the end of the post), who have updated to Phil’s 2009 paper Sustainable Energy Without the Hot Air – A New Zealand Perspective, which was published at Hot Topic. Inspired by the approach used by Cambridge physicist (and now chief climate change advisor to the UK government) David MacKay in his book of the same name, they bring a common sense perspective to the strategic energy debate we need to be having. Over to them:

Sustainable Energy – Without the Hot Air by Cambridge physicist David MacKay is an excellent and highly readable book of numbers about the questions associated with sustainable energy (available as a free download at www.withouthotair.com). As an advocate of sustainable energy, he describes himself as “pro-arithmetic” rather than a campaigner for one type of energy production over another, which is surely what informed debate needs. Rather than dealing with daunting numbers, he reduces energy calculations to units of kWh/day/person. 1kWh is the unit we pay for in our electricity bills — the energy used by one bar heater switched on for one hour. If you want to understand the which actions actually save energy (and which are just hype) then you need to read this book. Turning off a cell phone charger when not in use for a year saves the energy found in one hot bath. “If everyone does a little, then we will achieve only a little”.

The majority of MacKay’s calculations are done for the UK. Phil was interested in a New Zealand perspective and so published the original paper at Hot Topic in 2009 (found here). Oliver read McKay’s book earlier this year, came across Phil’s work (thanks to John Peet at Phase2 for the referral) and with his help updated the figures for 2012.

To this end, we have used a similar approach to look at two questions:

  • Can New Zealand maintain its current per capita energy consumption without fossil fuels and, in particular, can we live on renewable energy sources alone?
  • How can we achieve a BIG reduction in our personal and national energy consumption, in order to reduce our power requirements?

After completing the updated paper, we had a discussion with Gareth about the best way to publish the work and decided to run the report as a series of posts at Hot Topic. There are two reasons for this:

  1. Easier to get feedback issue-by-issue from the Hot Topic (and wider) community.
  2. It makes for a more palatable read than simply giving you folks a 22 page document.

This post today is a quick overview of the changes since the 2009 report, and serves as an introduction to the series which will appear at Hot Topic over the next couple of weeks.

For those that can’t wait, the full updated (2012) document can be downloaded here. Note it may end up being revised as your community finds errors in our work, so it might be better to wait till we’ve completed our series!

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Indonesian President promotes “sustainable growth with equity”

Indonesian President Susilo Bambang Yudhoyono gave an impressive speech at the Centre for International Forestry Research last week. How his words translate into the political life of his country I don’t know, but it is hard to fault them as an analysis of the world’s current challenges and a pointer to the direction in which we must move.   Not many political leaders take the time to stand back and present such a coherent and complete understanding of what is happening to human societies and the natural environment on which they depend. The speech is worth reading in full, but I’ll extract some of the salient points here.

His theme was sustainable growth with equity.

“What are our choices ?

“We can choose to continue to exhaust the present course, the same course that has been in place for decades and centuries. A world where we obsessively chase after economic growth without regard for ethics or the environment.  A world of excessive exploitation of resources, and insatiable consumerism.  A world driven by “greed” rather than “need”.

“If we go down this path, we will only find more of the same.  It will lead us to more environmental degradation.  More deforestation.  More pollution.  More global warming.  More endangered species.  More conflict between man and nature.  And ultimately, more desperation for the human race.”

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A Pathway to Sustainable Energy

“Will we look into the eyes of our children and confess that we had the opportunity, but lacked the courage? That we had the technology, but lacked the vision?” These words preface the report Energy [R]evolution 2012: A Sustainable World Energy Outlook published this month by Greenpeace, the European Renewable Energy Council and the Global Wind Energy Council.  It’s the fourth edition in a series which began in 2007. The publication is book length and over its pages describes a renewable energy scenario which sees CO2 emissions fall 85% from 1990 levels by 2050. I thought it well worth drawing attention to.

The authors can hardly be accused of utopian dreams. The technology exists to access stores of renewable energy far larger than the world’s energy requirements. The publication describes in careful and comprehensive detail an achievable programme of transition which would leave no need for the world’s fossil fuel resources to be pursued to the point of exhaustion or anywhere near it.  Carbon capture and storage is not part of the scenario, for reasons of cost and uncertainty; nor is nuclear energy, which, for reasons of cost, safety and inability to reduce emissions by a large enough amount, is marked for phase-out.

The reduction of demand through energy efficiency, the “sleeping giant” which offers the most cost-effective way to reform the energy sector, is a vital element in the transition. Over and over again surveys and analyses are making this clear, and the report is very much in line with an increasingly common theme in the literature.  High levels of projected energy demand diminish dramatically when energy efficiency is given high priority. The document shows the effect of best practice in various sectors of the economy.

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