If the answer is nuclear you don’t understand the question.

When selecting technology to solve a problem, a common method employed is to have “eligibility criteria” and “merit criteria”. Eligibility criteria are the must haves; if you are selecting a new machine to generate electricity “does it generate electricity” is the obvious one. Eligibility criteria are all pass/fail tests. Merit criteria are what you use to split all of the options that pass. Say you’re comparing a diesel or natural gas engine to power a remote site, a merit criteria could be “is fuel available all year round?”

In this post I will focus on the eligibility criteria for powering Australia while reducing the greenhouse gas emissions associated with electricity production. I will spend a long time arguing that, no, nuclear should not be considered, because it is utterly incapable of solving the problem. In later posts I will discuss the merit criteria, where again nuclear falls down.

The public conversation, for want of a better term, about nuclear power has become mired in a feelings discussion about whether or not someone “supports” nuclear power, usually in some sort of hypothetical vacuum. This discussion is almost entirely without value; how anyone can be for or against a technology is beyond me. The question with any technology is how it is applied.

For this conversation to have any value it must be carefully framed. More “is nuclear power a good response to mitigating climate change in Australia?” than “is nuclear power nice?” or even “if we have nuclear reactors already built should they stay open?”.

Despite the events in Fukushima, which many observers consider a disaster, nuclear still gets a look in as a policy response to climate change. Most of the commentary surrounding the release of the White Paper focused on the favoritism or otherwise shown for nuclear power, and public advocates like Barry Brook still poke their head up  and shout “NUCLEAR” from time to time. While I will admit some of them have a point, anyone seriously advocating nuclear power as a policy response to global warming in Australia doesn’t understand the problem.

How does nuclear even get a mention in this discussion? There are two reasons in particular, and I admit they are quite compelling.

The first eligibility criterion for addressing electricity generation emissions is whether the technology generates less greenhouse gas than the technologies it will replace. This is determined using the full-cycle emissions intensity, which is the sum of all the emissions during production, mining, operation and decommissioning, divided by the generated electricity. It is hard to imagine any generation technology being truly zero emissions, as windmills require steel, solar panels require silicon and even hydro can release methane.

The figures below are Australian numbers, calculated by a team from the University of Sydney. In these comparisons it is vitally important to use region-specific data, as the emissions of construction are heavily driven by the emissions intensity of local electricity. Cement for example will usually be manufactured locally, and so the emissions of that process are governed by the grid emissions. Cement is a significant component of a nuclear plant, and so one drives the other.

Nuke_Emissions

Emissions intensity of a range of generating technologies. Figures in brackets indicate range. Taken from Lenzen, M (2008), linked from the image.

These figures were calculated before grid emissions and annual demand started trending down, which began in about 2009. The author notes that they assume that any new grid capacity will be best practice, which should drag the future emissions intensity broadly into line with current data. A motivated individual could go through the paper, determine the grid emission component of the energy use and then apply the curves, but it won’t be very much fun. It is sufficient to note that the emissions are likely to be lower than published, but not very much. This applies to all technologies, not just nuclear.

Over their lifespan nuclear power plants produce emissions per MWh somewhere between wind and solar, and about 10% of the emissions of a combined-cycle gas turbine, one of the most efficient conventional generators available. So a pass for nuclear on emissions intensity.

While this seems unintuitive, nuclear power plants are gigantic things made out of concrete and steel, a slow nuclear bomb in a box, while solar panels can go on the roof of your house, it starts to make sense once you analyse the other side of the metric. Nuke plants produce vast amounts of energy, due to the astonishingly high energy content of uranium.  The table below compares the energy content, in terms of electricity production, of a number of fuel sources. LEU at the bottom is enriched uranium, and the numbers are truly astounding.

energy-fuel-comparison-600x385

Comparison of fuel energy content. The link through to the post that came from is worth a look, and includes an analysis of whether we have enough uranium to replace current energy sources.

This energy density sets it apart from coal, despite the generating technologies being very similar. Both plants make steam and drive a turbine to make electricity. Where a coal plant is very much a throughput problem, in the order of 100kg coal per second is required to keep an average plant running, nuclear plants require very little fuel, and the problem is getting the energy out of it slowly enough.

The second criterion, which might seem slightly ludicrous, is whether it is physically possible to make enough electricity from the technology. These calculations are most often applied to biofuels options, but are equally valid for electricity generators.

The high energy density of uranium means that the technology is quite space efficient, a key advantage over current renewables. As a coarse estimate, we could replace all the coal generation in Australia with 25 or so plants, and provide all of our energy with 50ish, depending on what you include and grid requirements for peaking power. To do the same job with wind would be more in the order of 50,000 – 75,000 turbines, or a square 100km by 100km with solar panels.

So, I concede, when considering the hypothetical, technology assessment of nuclear, it sounds useful. Loads of energy, low emissions. But how appropriate is nuclear power as a response to climate change?

The warnings we routinely ignore from the International Panel on Climate Change are unequivocal; everyone must reduce their CO2 emissions by 40% by 2020 and by +90% by 2050. Nuclear power in Australia should only be considered within this context, because if you don’t care about climate change then we might as well burn all the coal we have. And we have a lot.

The current policy combination of the Renewable Energy Target and the carbon price seems to be working, although probably not quickly enough to hit those targets.

Cedex

What happens then if we decide on the 1st of January 2013 that we are going to go nuclear and start construction on the same day?

There are two things to consider when analysing the impact on emissions a new build can contribute; how quickly can you build it and how long will it take to pay back the emissions from the construction phase?

Build times vary, depending on your source, but there are a few builds underway to provide some signposts.

In 2009 the UK government decided to build 10 plants. That is just actual power plants, they already have an established nuclear power industry and will be able to leverage some skills and infrastructure that Australia doesn’t have. I’m having trouble finding references on construction time, but this is indicative “Ministers hope to fast-track the construction of the new plants so that some can be producing energy by as early as 2018.” Nine years from “yes we’re doing this” to electricity. Other similar builds in Georgia (US), France, China and Finland are on track for about 8-9 years as well.

Electricity production would commence in 2022 in the Australian scenario. Two years after our emissions should be 40% less.

Any low emissions technology now has to start saving tonnes of greenhouse gas to earn back the construction emissions. It won’t be making a positive contribution to greenhouse gas mitigation until it has saved more tonnes than it cost to build.

The whole of life cycle comparison between construction emissions and tonnes saved is incredibly complex and thus susceptible to a large degree of error. How do you account if the contruction emissions are 90% diesel, but it only offset electricity use? Do you include projections for average emissions intensity in the offset of electricity? This whole difficult metric is often referred to as the carbon payback, and is the sort of thing that requires a thesis to calculate properly. Some numbers are available, wind here with a payback of about 3.5 years,

A reasonable proxy then is the simple energy cost of production against the time it takes to generate that much electricity. Often called energy payback.

As emissions have been removed from this calculation regional variance is less significant. However, Lenzen (2008) linked above, has calculations for Australian conditions. Page 7 here makes it pretty clear:

The energy payback time of nuclear energy is around 6½ years for light water reactors, and 7 years for heavy water reactors, ranging within 5.6-14.1 years, and 6.4-12.4 years, respectively.
So if we start construction at the beginning of 2013, nuclear power will start reducing Australia’s emissions from electricity production in about 2028.
Any comparison with wind or solar will need a detailed list of assumptions, but reporting a range is close enough. The graphic below plots “energy return on investment” for various sources, which is an analog for energy payback. It is the ratio of electricity generated over the lifetime of the plant and the energy used in construction and operation. Higher numbers mean shorter payback.
The Offshore Valuation: A valuation of the UK’s offshore renewable energy resource. Published in the United Kingdom 2010 by the Public Interest Research Centre. ISBN 978-0-9503648-8-9 www.offshorevaluation.org PE (2006)

The Offshore Valuation: A valuation of the UK’s offshore renewable energy resource. Published in the United Kingdom 2010 by the Public Interest Research Centre. ISBN 978-0-9503648-8-9 http://www.offshorevaluation.org PE (2006)

I haven’t seen Australian figures for this and would be interested to see them done, but other sources support the values above. Converting these to energy payback puts wind at 6 months to 2 years and solar at 1.5 to 5 years. As these are renewables their output will of course depend on their location.
It should be clear by now that if your goal is to reduce emissions as quickly as possible the best way to achieve that is using renewables. Nuclear power actually cannot contribute in the next 15 years. And that’s from the start of construction. One expects that overcoming the public opposition to nuclear, and getting it onto the political agenda will take years on its own.
Advocating for nuclear power in Australia is advocating to do nothing about our emissions until almost 2030. Wind, solar and energy efficiency are reducing our emissions right now and will continue to do so.
The very reasonable point has been raised elsewhere that the above does not address the long term scenario; could nuclear contribute substantially in the 2050 scenario?
The incredibly thorough UMPNER review, released in 2007 doesn’t offer much hope:
The greenhouse gas emission reductions from nuclear power could reach 8 to 17 per cent of national emissions in 2050.
So if we abandoned the 2020 target of a 40% reduction, went nuclear and held out hope for hitting the 90% by 2050 target, we would also fail fairly spectacularly. Further, if we miss the 2020 target we also need to offset those additional emissions in later years.
So if your answer is nuclear, you don’t really understand the question.
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About evcricket

Extreme gardener, engineer and bird nerd. View all posts by evcricket

24 responses to “If the answer is nuclear you don’t understand the question.

  • l.baxter (@tredlgt)

    Thanks for this, informative, no bulls. This is what is missing from OM. also enjoyed chookwatch and plant rustling tweets.

  • Tom

    You’ve brought out some really good information here, but I have to disagree with your conclusion – we can’t rule out nuclear yet.

    There are a couple of key problems with wind and solar: they deliver much less than their rated output much of the time (e.g. PV cells at night), the power output can fluctuate rapidly (large solar installations with intermittent clouds can cause power system instability), and their peak output is rarely at the same time as peak demand.

    Conventionally this means that you must back up all of your renewables with nearly as much non-renewable generation. It takes a long time to fire up coal power turbines from a cold start so if there is a risk that they will be needed they must be left idling, burning coal for no gain.

    Nuclear power generation doesn’t suffer from these difficulties because it is a continuous controlled source of power. Now, obviously this doesn’t do anything about the payback period – this is still an important problem in terms of hitting the targets we want.

    The reason nuclear power is still part of the discussion is that we are likely to be screwed _no matter what we do_. If we can’t solve the problems with wind/solar/etc. then nuclear may be the best of a bad bunch of options when we’re trying to play the long game.

    To end on a more positive note, hopefully nuclear power will be trumped by massive advances in energy storage technology. If we get to the point where it’s cost-effective and space-effective to install batteries that can power entire streets for reasonable periods of time, we will be able to use solar and wind to charge those and avoid all of the above problems. Sadly we are a long long way from that point, so I wouldn’t suggest we put all our eggs in that basket now.

    • evcricket

      Yes Tom, agree that wind and solar bring their own problems. Nuclear actually does suffer from some serious supply limitations, as it is a thermal power system, that means to turn it up and down is either very slow or very inefficient/water costly as the spare energy must be vented as steam. In any case, I’ll come back to these points in subsequent posts, and include some detailed discussion on storage, which is actually where my expertise lies.

  • Sean

    Seems the massive construction lead times, the need to have all sorts of skillsets and techniques rule out current technology nuclear for at least the first half of this century.
    How challenging is it to scale the cheaper renewables?
    Thanks for another informative post Ev.

  • David Caldwell (@roodave)

    Hi I’m just wondering how this answers the base-load issue? the report you cite seems not to address efficiency/ cost/ environmental life-cycle issues of storage systems to support inherently inconsistent sources like solar, wind and hydro? Sorry if I missed something here, I only skimmed the ISA report, but I would have thought the key difference between coal/ gas/ nuclear and renewables is that they are “on demand” and not subject to the vagaries of a cloudy day etc.

    • evcricket

      Hi David. You have touched on some useful points, but they don’t affect the one point I wanted to make in this post; nuclear can not reduce our emissions before 2030. Knowing that, we work within this constraint.

      As I’ve said elsewhere I do not agree that “baseload” should be a generating technology goal. Again, I’ll go into this in the subsequent Merit Criteria posts.

    • Rik

      One useful way of looking at storage is that in many ways it replaces and improves the efficiency of the national grid, so much of its cost can be struck off against the benefit of reduced maintenance and upgrade costs on the grid.

      Centralized generation requires an added grid infrastructure cost, distributed+intermittent generation requires an added storage cost. When considered in these terms the point at which storage is practical (in terms of $/kwh) becomes very achievable.

  • IainM

    I still don’t really understand why people seem to assume nuclear has to be an alternative to renewables (at the policy level). Yes, renewables, efficiency etc probably are the best response in the short term. Yes, nuclear alone cannot “get us there” in the long term -by itself-. But we have to remember that the marginal cost of emission reductions rise as emissions fall (speaking both financially and in more generic terms of difficulty). As I understand it, there are good reasons to think nuclear might take us from -80% to -90% emissions more readily than other technologies. Of course we still should consider our options carefully, but the sort of analysis above that ignores this context is just as unhelpful as much of what else is out there.

    • evcricket

      It kind of does need to be a choice between nuclear and renewables; nuclear is far more cost effective the more plants you run. I will talk about this in more detail in the later Merit Criteria posts.

  • Christina MacPherson

    In the discussion here of the greenhouse gas emissions from the nuclear fuel cycle., “mining, operation, and decommissioning” are included. This is good to see, as most often, the “operation” only is considered, in this.
    However, “decommissioning” is a lovely vague word, applied to dismantling the nuclear reactor.
    What is not mentioned here is the greenhouse gas emissions from the huge process of digging the nuclear waste tomb, and also from all the transport involved in this.

  • Why nuclear power is utterly incapable of tackling climate change « Antinuclear

    […] I haven’t seen Australian figures for this and would be interested to see them done, but other sources support the values above. Converting these to energy payback puts wind at 6 months to 2 years and solar at 1.5 to 5 years. As these are renewables their output will of course depend on their location. It should be clear by now that if your goal is to reduce emissions as quickly as possible the best way to achieve that is using renewables. Nuclear power actually cannot contribute in the next 15 years. And that’s from the start of construction. One expects that overcoming the public opposition to nuclear, and getting it onto the political agenda will take years on its own. Advocating for nuclear power in Australia is advocating to do nothing about our emissions until almost 2030. Wind, solar and energy efficiency are reducing our emissions right now and will continue to do so. The very reasonable point has been raised elsewhere that the above does not address the long term scenario; could nuclear contribute substantially in the 2050 scenario? The incredibly thorough UMPNER review, released in 2007 doesn’t offer much hope: The greenhouse gas emission reductions from nuclear power could reach 8 to 17 per cent of national emissions in 2050. So if we abandoned the 2020 target of a 40% reduction, went nuclear and held out hope for hitting the 90% by 2050 target, we would also fail fairly spectacularly. Further, if we miss the 2020 target we also need to offset those additional emissions in later years. So if your answer is nuclear, you don’t really understand the question. https://evcricketenergy.wordpress.com/2013/01/01/if-the-answer-is-nuclear-you-dont-understand-the-que… […]

  • Forget nuclear power as an answer to climate change « Nuclear Australia

    […] I haven’t seen Australian figures for this and would be interested to see them done, but other sources support the values above. Converting these to energy payback puts wind at 6 months to 2 years and solar at 1.5 to 5 years. As these are renewables their output will of course depend on their location. It should be clear by now that if your goal is to reduce emissions as quickly as possible the best way to achieve that is using renewables. Nuclear power actually cannot contribute in the next 15 years. And that’s from the start of construction. One expects that overcoming the public opposition to nuclear, and getting it onto the political agenda will take years on its own. Advocating for nuclear power in Australia is advocating to do nothing about our emissions until almost 2030. Wind, solar and energy efficiency are reducing our emissions right now and will continue to do so. The very reasonable point has been raised elsewhere that the above does not address the long term scenario; could nuclear contribute substantially in the 2050 scenario? The incredibly thorough UMPNER review, released in 2007 doesn’t offer much hope: The greenhouse gas emission reductions from nuclear power could reach 8 to 17 per cent of national emissions in 2050. So if we abandoned the 2020 target of a 40% reduction, went nuclear and held out hope for hitting the 90% by 2050 target, we would also fail fairly spectacularly. Further, if we miss the 2020 target we also need to offset those additional emissions in later years. So if your answer is nuclear, you don’t really understand the question. https://evcricketenergy.wordpress.com/2013/01/01/if-the-answer-is-nuclear-you-dont-understand-the-que… […]

  • Robert Merkel

    Given that the CO2 will stay in the atmosphere for centuries (at a minimum) I don’t see why it is so important whether the emissions from a particular generation technology are front-loaded or back-loaded.

    As for the UMPNER projections, I think it grossly mischaracterises that report to say that the 17% represents an upper bound of the contribution nuclear power could potentially make. For instance, it doesn’t consider the effects of electrification of transport at all.

    That report, incidentally, neatly shows the danger of assuming too much about the future architecture of energy supply – for instance, the assumption that grid demand would just grow into the never-never seems to have been fairly strongly contradicted by the experience of the past few years.

  • Backslider

    Renewables will never, ever generate baseload power. You are dreaming sonny.

    There is actually no empirical evidence to show that CO2 causes any warming that we need to worry about. The CAGW scam is now on its last legs, please keep up.

    • evcricket

      Great comment, neatly illustrating the paucity of debate by those opposed.

      Hydro generates power whenever anyone wants it, right now. So does biogas. So does geothermal. So does solar thermal with storage.

      I have inquired about what would constitute empirical evidence of climate change, if any exists, and none of those opposed have been able to describe what data would support the AGW theory. Maybe because they don’t understand it?

  • Frantic

    You get lost in your “analysis ” when you fail to compare the environmental cost of building a reactor to those of building an equal production/ output number of solar cells or wind turbines Do a bit of simple math for us 50-70,000 wind turbines at 500tons of steel each = 25million tons of steel. Each of which has to be shipped from china in a polluting bunker fuel burning ship then transported to rural / remote areas, erected using diesel powered mobile cranes and have infrastructure built to take the power generated back to populous centres.
    A set of reactors would use far less steel or concrete than 50,000 wind turbines, and be located more easily to connect to the majority of the population.

  • Frantic

    Ok so lets change your original opposition from resources used and their carbon cost, as it will be far greater with wind,to time taken. How long will it take to build 50,000 turbines, ship them here( they require specialist ships to get the blades here= more fossil fuel wastage and limited by slow supply) . Build them in a remote area, then bulldoze the forests/farms to lay the infrastructure required for power generation.
    Do an even fair comparison, otherwise your just showing a bias. Show the full construction, transport and linking to grid costs ($ and carbon)of geo, wind and nuclear along with timeframe to build.
    Further stating that we would need 25 reactors is technically true but in reality it would be more like 4-5 plants with 4-5 reactors at each site so could be misinterpreted. This would make it more environmentally friendly and allow the power gen to ramp up over time along with reduced linkage costs.

  • wideeyedpupil

    DIY comparison, Frantic. To get started download the Beyond Zero Emissions Stationary Energy Report as a free PDF and you will find data for BOM for a 2MW wind Turbine installed in La Rioja, Spain. p 101 Table 6.3. It’s similar in size to the turbines proposed in the Zero Carbon Australia Stationary Energy Report.

    You will also find calculations for the transmission line construction timelines and material use. Same info provided for the SolarCST which makes up the other large generation component of 100% renewable solution. 50GW wind generation with 42.5GW of SolarCST with molten slats storage has been found in modelling (using 2008 and 2009 insolation, wind data and NEM demand on half-hourly scale) to meet 98% of projected energy demand — and that’s including the electrification of industrial processes using gas and the transport sector. The remaining 2% can be meet buy burning (available) bio-waste at SolarCST plants to drive turbines. See Part 4 of ZCA SEP. Modelling was provided by Jack Actuarial Consulting Pty Ltd.

    This plan costs about the same as Business As Usual. Given the rising costs of fossil fuels and increasing cost of risk adverse money supply to fossil fuel based investments it could well turn out to be a lot less expensive the BAU in a decades time. And the bonus is we play our part in not destroying our (relatively but increasingly less so) safe climate.

  • cfable

    I’m not an Engineer and was once a supporter of solar, but far less so now. Lets say we have a city of a million people and we’re going to provide electricity using solar alone. Because the sun sets we’ll back it up during the night using a hydro scheme. How many solar panels will be required to run the city during the day AND pump all the water back up the hill, just as fast as it ran down during the night
    .
    Remember when calculating the number of solar panels that will be required, we need to consider how much energy can be collected on an overcast winter solstice, when the sun’s 22.0 lower, compared to a sunny summer solstice. These are the locked in parameters of energy that are available. Also 240 volts is completely useless to a city grid, so we’re going to need massive Inverters (?) to get the voltage right up to overcome the resistance of the grid. Not to mention Industry uses 3 phase power based on 315 volts. I know Inverters heat up, so use power too. (Personally I don’t think you can make solar panels do the job)

    How long will it take to build a suitable dam with an over capacity to ward off evaporation and drought. Dozens of 2m. pipes running down the hill through a massive hydro power station and into a huge holding pond. Don’t forget the massive pumping station to push the water back up the hill at the same volume.

    Would the lead in time be the same as building a Nuclear powered generator of the same capacity? Requiring one lot of infrastructure, one capital outlay and one fight to get it through.

  • Zvyozdochka (@Zvyozdochka)

    (Note to self – must read more cricket-work).

    Plus, and besides, at the end of 2022 you have VERY expensive electricity.

  • Is nuclear a good investment? | Evcricket's Energy

    […] the much belated follow up to the eligibility criteria post on nuclear power, I consider the first merit criterion; is nuclear power a good investment? Is […]

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