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Zero Carbon Australia: We can do it

Posted on 19 March 2011 by James Wight

My recent post about long-term CO2 targets was rather doom-and-gloom: I concluded that we must phase out fossil fuels to keep the climate in the range that humans have experienced. The good news is that action on this scale is not only possible but surprisingly feasible.

Last year, the University of Melbourne Energy Research Institute in conjunction with Beyond Zero Emissions produced the Zero Carbon Australia 2020 Stationary Energy Plan. The ZCA2020 Plan outlines an ambitious and inspiring vision: to power Australia with 100% renewable energy in ten years.

The report that has been released only covers emissions from Stationary Energy (though it does refer to electrifying transport). Five future reports are planned on how to eliminate emissions from other sectors (Transport, Buildings, Land Use and Agriculture, Industrial Processes, and Replacing Fossil Fuel Export Revenue).

Why do it, and why now?

As I’ve explained here, to prevent “dangerous anthropogenic interference with the climate system” we must reduce CO2 to below 350 ppm. That necessitates a rapid transition to a zero-carbon economy.

A common approach is to define a quota of allowable future global emissions to limit warming to less than 2°C above preindustrial levels, and divide them up by nation per capita. At Australia's current rate of emissions, we will use up our share of the global budget in just five years (the same goes for the US and Canada). This gives Australia about a decade to make the transition.

Global Carbon Budget for Emissions

Figure 1: CO2 emissions budget for selected nations.

That’s why Zero Carbon Australia 2020 is not a low emissions plan but a zero emissions plan. This is a fundamentally different way of thinking about the problem. It goes straight to zero emissions technologies, without a detour through low emissions ones which would waste time and resources.

If the Plan is adopted later it could still meet a later deadline. But obviously, further delay means ever increasing risks – and the risks are already very high.

What energy sources would power Australia?

The Plan chose only technologies that can meet demand, can be implemented within ten years, are already commercially available, and (obviously) are zero-carbon, not counting emissions from construction.

60% of the grid would be powered by concentrating solar thermal (CST). The other 40% would come from wind turbines. The Plan also includes small-scale solar to reduce the grid demand during the daytime. Biomass and existing hydroelectric would be used as backups.

Of course, this is only one possible scenario. Technologies that become available in future could increase our options and reduce the cost.

Nuclear power was not considered because the implementation time is longer than a decade. Hydro and biomass are limited in scalability for unrelated environmental reasons. Wave, tidal, and geothermal are promising technologies but not yet ready. Carbon capture and storage is neither commercially available nor zero-carbon.

How would they provide continuous power?

A common misconception is that renewables can’t provide continuous (“baseload”) power. But the technology of concentrating solar thermal can. It was proven at commercial scale in the 1990s. The US Department of Energy lists several dozen solar thermal plants currently in operation.

Here’s how it works. Mirrors called “heliostats” track the Sun and focus sunlight onto a central “power tower”. This energy is stored in molten salt as heat, warming the salt to 565°C. This energy storage has an efficiency of up to 93%. To produce electricity, the hot salt is pumped into a generator, where the heat is transferred to steam which drives a turbine. Once the salt is cooled to 290°C (still warm enough to be molten), it returns to the tank to be reheated.

Solar Thermal Power Tower

Figure 2: Diagram of a concentrating solar thermal power plant.

The Sun doesn’t shine at night, but this is not a problem for a solar thermal plant because it has a store of energy ready to go at any time. CST can produce power around the clock. The ZCA2020 report describes it as “better-than-baseload” because it is more flexible. CST works well with wind power, because the stored solar energy can be used when there is not enough wind.

As the cheapest form of renewable energy, wind can provide a generous portion of our electricity. Because the wind isn’t blowing all the time, wind farms average only 30% of their capacity. At least half of the electricity produced (ie. 15% of capacity) is expected to be as reliable as “baseload”.

Finally, the Plan includes more than enough backup biomass capacity to fill the gaps created by worst-case weather. The hydro and biomass backups are required for just 2% of demand.

The report modeled the ZCA2020 grid, based on real-world insolation and wind speed. They assumed a demand 40% higher than today (accounting for increased energy efficiency and electrification of transport and heating). The modeling confirmed the proposed portfolio of solar, wind, hydro, and biomass would indeed supply demand.

How much solar and wind must be built, and where?

Proposed Power Grid for Renewable Electricity

Figure 3: Map of proposed sites. Yellow squares are solar power plants, blue squares are wind power plants, red lines are high-voltage direct current transmission, and green lines are high-voltage alternating current transmission.

The Plan proposes 12 CST sites, each with 13 major power towers, each power tower with 18,000 heliostats. Together, they would have a total capacity of 42.5 GW and be able to store enough energy to meet winter demand.  

The proposed locations are near Bourke, Broken Hill, Carnarvon, Charleville, Dubbo, Kalgoorlie, Longreach, Mildura, Moree, Port Augusta, Prairie, and Roma. These towns are far enough inland to have high sunlight throughout the year, but close enough to the populated coasts for it to be economical to build high-voltage transmission lines.

Each site would measure approximately 16 by 16 km. The total land used would be less than 3,000 km2. That’s comparable to Kangaroo Island, smaller than some large cattle stations, and 0.04% of the area of Australia.

To provide enough reliable wind power for a 40% target, we need a total capacity of 50 GW, 25 times what it is now. The best commercially available wind turbines have a capacity of 7.5 MW, so we need to build 6,400 of them. Land covered by wind turbines can still be used as farmland.

The Plan proposes 23 sites dotted around the coast. The locations are widely dispersed so the grid is not dependent on the weather in any one place. They are also chosen for high wind speeds in winter, when less solar power is available. Each site has annual average wind speeds of at least 25 km/h.

To put all this in perspective, some other nations are investing in renewables on a large scale. China already has 25 GW of wind capacity and will have 150 GW in five to ten years. Denmark has a target of 50% wind power by 2025. And Spain will have 2.5 GW of solar thermal capacity by 2013.

What is the timeline?

The CST plants would be built in two stages. The first stage would begin by constructing small power towers and gradually ramp up until 2015, when solar power costs become competitive with coal power. The majority of the power supply would come online during the second stage, with a constant rate of manufacture to 2019.

Wind would be scaled up faster because it is cheaper and there are already a number of installations in the pipeline. New projects would start every six months and take a year to complete. A three-year ramp-up should lower the cost to European levels, also followed by a constant rate of construction.

What resources are required?

The Plan involves building 23,000 km of high voltage transmission – both to connect the new power stations to the grid, and to connect the multiple existing grids to each other (so supply does not depend on the weather in one place).

At peak construction, the Plan requires 600,000 heliostats and 1,000 wind turbines per year. These could either be mass-produced in Australia or imported. In Australia it could create 30,000 jobs in manufacturing.

The plan would also create 80,000 new construction-related jobs, and 45,000 ongoing jobs in operation and maintenance, replacing an equivalent 20,000 in fossil fuels. In addition, the 30,000 manufacturing jobs could also be retained to export components to the world. Some solar jobs would even be in the same areas as lost mining jobs.

The concrete needed is a tiny fraction of Australia’s resources, and the steel a tiny fraction of our exports. A solar power plant uses merely 12% as much water as a coal power plant. However, we would need several new factories producing glass and other materials.

How much will it cost?

The total capital cost over the decade is $370 billion, or 3% of GDP per year. That’s about the amount of money spent on insurance, or the value added by the real estate sector, or the money spent on coal, gas and uranium. Most of the money is spent in the latter half of the decade, after the public has already seen some of the benefits of the initial investment.

About half of the money, $175 billion, would be spent on solar thermal plants, as well as $92 billion to upgrade the grid, $72 billion on wind turbines, $17 billion on off-grid solar, and $14 billion on biomass. However, the Plan looks at these costs as an investment. It leaves open the question of where the funding would come from, suggesting a combination of public and private sources.

The investment pays itself back by 2040 or as soon as 2022, depending on which costs you count. The Net Present Cost over the period 2011-2040 is equal to business-as-usual (BAU) if you only include direct costs. Though the capital costs of ZCA2020 are much higher than BAU, more money is saved because solar power plants do not need a constant supply of coal and gas for fuel. If you also take into account the Net Present Cost of oil and (possibly) priced emissions under BAU, ZCA2020 could potentially save $1.5 trillion.

Economic Model Comparison

Figure 4: Net present value of ZCA2020 Plan compared to business as usual.

All the above completely ignores climate and environmental costs, which obviously would heavily favor ZCA2020. The Stern Review estimated that a global effort to mitigate climate change could save 20% of GDP per year by 2050.

The effect of the transition on electricity prices depends on how it is funded. In one possible scenario, they could rise by $8 per household per week, similar to what is expected under BAU.

What will happen to the fossil fuel industry?

The report does not address this as it is a political question. However, it does point out companies were aware of the risk to their industry when they invested in their assets.

How do we convince our leaders this is a good idea?

Now I wish I knew the answer to that one. When Australia (and the world) finally wakes up to the climate crisis, Zero Carbon Australia 2020 provides a useful blueprint for decarbonising our energy sector. But we’d better wake up pretty damn quick.

Societies have shown that they can be mobilized by ambitious visions. When J.F.K. proposed landing a man on the Moon before the end of the 1960s, it seemed incredible. Yet the goal was accomplished twice before the deadline.

So far Australia has not shown leadership on clean energy, preferring to see itself as a mining nation. Renewable energy entrepreneurs are going overseas because there is no market in Australia. Yet we have vast untapped renewable resources.

Global warming is a very real and urgent threat. As an extremely high per capita emitter Australia has an imperative to take drastic mitigating action. ZCA2020 shows powering Australia with renewable energy is feasible using commercially available technology. Solar thermal can provide better-than-baseload power. The transition would stimulate the economy, save up to $1.5 trillion by 2040, create jobs, and make Australia a leader in clean energy. So what are we waiting for?

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Comments 1 to 50 out of 120:

  1. Thanks for the article, James.

    A couple of engineering-type questions:

    1) Do you know if the ZCA analysis looked at Brayton cycle generation for the solar thermal (as the CSIRO is looking at in their prototype plant at Newcastle), rather than steam generation? They give significantly higher thermal efficiency. I understand, though, they generally stuck with "off-the-shelf" technology, and thermal-powered supercritical steam turbines are exactly that - I'm not sure if there's an "off-the-shelf" Brayton cycle technology out there;

    2) How would the generation output from the solar thermal be affected by a La Nina such as we're having now, with significantly higher cloud cover and cooler temperatures than 'average' for Australia? BoM data shows some of the sites have received 400% of their average rainfall for the past three months - particularly the Mildura area.

    I know that point 2 can be partially solved by over-building capacity, but that comes at a significant cost, if you're looking at an extended period with, say, 20-30% less insolation. Having said that, I imagine air-conditioning demand has been significantly lower than usual this summer...
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  2. "I imagine air-conditioning demand has been significantly lower than usual this summer..."

    I rather think that's an issue that needs to be publicised more. When we hear complaints that some renewable source or other 'doesn't work when...', more often than not that self-same condition moderates demand for heating or cooling.

    The more important thing is to look at the mismatches. When are conditions adverse to generation likely to coincide with demand increased by exactly those conditions. Not too many - but that's just my impression for Australia. No idea about countries or areas subject to snowstorms, ice, tornadoes and the like.

    Anyway, storage technologies should take care of most of it. And they will certainly advance to commercial rollout within this timeframe.
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  3. I'm sorry, I missed a point. A windmill is made of steel (or carbon fibers) and concrete. How do you produce them without FF (and even dissociation of calcium carbonate produce CO2) ? electricity is transported by copper (or aluminium) wires : how do you produce them without FF ? how do you carry and erect the windmills without FF ? how do you travel across Australia without FF ? how do you power trucks, boats and planes ? how do you make isolators, paints, elastomers, fertilizers ?

    you concentrate on power generation. May be you're ignoring that some countries have ALREADY electricity with a very low or zero carbon intensity : Norway, Iceland, some canadian provinces, thanks to hydroelectricity , France, thanks to nuclear. Here are their CO2 production per capita :

    Norway : 9.1
    Iceland : 7.6
    France : 6
    Quebec : 11.1
    the average is around 8 TCO2/capita. Note that 8 times the soon 8 billion people in the world are 64 billion t CO2 per year ( !!!!)
    so what do yo say to these countries to reduce this production ? forgive the electric power - it's already solved. What do you say them for all the rest ?
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  4. That is pretty weak Gilles.

    The Plan does not call for zero emissions tomorrow but rather once the generation is built.

    As for the other countries CO2 emissions, that would be off topic and beside the point. The title clearly states "zero carbon Australia". Scientists and engineers in other countries around the world are undoubtedly addressing their unique challenges in creative and ingenious ways and are not likely to be troubled with your pessimistic, can't do attitude.
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  5. Gilles,
    You forgot to read the post again. The third paragraph says "Five future reports are planned on how to eliminate emissions from other sectors (Transport, Buildings, Land Use and Agriculture, Industrial Processes, and Replacing Fossil Fuel Export Revenue)."

    It is good to have you point out that many developed economies have lower carbon intensities than the USA and Australia. If we all copy the features of these countries we can all reduce carbon emissions. And it has already been proved that does not reduce quality of living!
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  6. I note with interest, Gilles, that you're again pushing fossil fuel industry propaganda down our throats. Even with the CO2 footprint of wind farm construction (which can be reduced via advances in low energy concrete & steel production that already exist, & are being improved every day), the life-time CO2 footprint of a wind turbine-or solar collector, or photovoltaic cell-is still less than 1% of that of coal (in gCO2/kw-h of electricity). Of course we've already told you-though you're *clearly* not listening-that our transportation needs can be achieved, with a much, much lower CO2 footprint, using either bio-diesel (from algae) or electricity from renewable energy sources-indeed, Iceland is on the verge of cutting its per capita CO2 emissions still further by shifting the bulk of its transportation from fossil fuels to hydrogen. Given that many of the nations on that list you supply generate 2 to 3 (if not 4 to 5) times as much CO2 per capita as the nations you selected, I'd argue that its far better that we try & cut our CO2 emissions down to those of Iceland or Norway, rather than keep them at the level of Australia or the US-which will result in CO2 emissions of closer to 150 billion tonnes per annum, not 64 billion.
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  7. "how do you power trucks, boats and planes ? how do you make isolators, paints, elastomers, fertilizers ?"

    You need to get your head *out* of fossil fuel industry pamphlets, Gilles, & instead read the stuff being published in scientific & engineering journals. Every week I seem to learn about something that can now be done *without* the need for oil-or any other fossil fuel. Plastics & Fertilizers are already available that don't have a single ounce of petrochemicals in them. Its the same source from which I find out about new methods for significantly reducing the initial CO2 footprint of building renewable energy systems (things like e-crete, which goes back to the Roman method of cement production-using aluminium silicate instead of the much lower quality Calcium Oxide based cement, or steel made using arc-furnaces & recycled steel-thus requiring only 1/4 of the energy needed to make the steel from scratch using outdated blast furnace technology) & new, renewable fuel & energy technologies.
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  8. I just said that several countries had ALREADY achieved a zero or almost zero electricity production, and that their carbon emission weren't negligible at all, and I gave the figures. So can you explain me WHY all these countries (including Iceland that has no FF at all and must import everything) still keep using FF if they could suppress them? well may be they are kept hostages of bad oil and gas industry ... but.. why and how did they achieve their geothermal and hydroelectric power plants , in this case? is there a strange international disease that would everybody like electrons from renewable water, but not from renewable air or solar photons ?
    I was in iceland last year. I saw a BP hydrogen station in Reykjavik (actually I think there are a few of them). Very nice green paints. Unfortunately, not a single car stopping at them. May be some buses stop there from time to time , but I missed the time; no information in the tourism office, unfortunately. I never heard of anything concerning hydrogen when I travelled across the country - I cannot imaging hydrogen refuelling in all the small villages and lunar landscapes I went through.
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  9. and Marcus, again : if you understand that I'm claiming that it is not worth improving our energy efficiency and save FF, you totally misunderstand me. I'm sorry you're not able to get what I'm really saying - although as a teacher I am somewhat used to this kind of situation.
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  10. Gilles, you seem to suffer from a lack of imagination.

    You think that just because things are done with fossil fuels now, that there is no way that they can be done *without* fossil fuels in the future.

    Well, the whole point of this article is to show that the opposite is true - there *are* ways of doing things without fossil fuels. So we might use some coal-fired electricity to build the first few renewable sources. The point is, the more we build, the less coal we burn, and the less fossil energy goes into producing the next round of renewable sources.

    Back on the topic at hand - I like the molten salt storage option the ZCA report examines. It gives enormous flexibility in the actual source of the energy.
    Concentrating solar is the source discussed here, but literally any source of heat will work - including geothermal, biomass (the 'backup' ZCA option), or nuclear. You could, potentially, even use it as a storage for electricity generated by other renewable means, although there would be significant losses involved there, in converting the electricity into heat, and then back again when you needed it.
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  11. Adelady @ 2: yes, demand does fluctuate considerably. The question is whether it reduces as much as the generation does.

    I downloaded demand data for Queensland from the Australian Energy Market Operator (AEMO) website (demand data found here) for the month of December in 2009 and 2010. Dec 2010 was significantly wetter than 2009. Looking up the BoM data for solar exposure at Roma (one of the locations ZCA proposes for a CST field), we have Dec 2009 average of 7.5kWh/m2, compared to 6.9 for 2010.

    But there was a significant reduction in electricity demand - about 9.1% across the board (with peak demand showing the greatest decrease of about 10.5%, and minimum demand dropping 8.5%). So that's an 8% drop in solar energy input, averaged over the month, compared to a 9% drop in electricity demand. Those numbers look pretty good!

    At the top end, that's a difference of 850MW of electricity generation - or more than the entire output of the Kogan Creek coal-fired power station. Peak demand was 8,804MW in Dec 2009. At 217MW a pop (the numbers ZCA gives for the solar thermal units), we'd need 41 of those solar thermal towers, plus backups. Call it 50 total. At the ZCA price of $739m per, that's $37billion to completely de-carbon Queensland's electricity supply.

    Sounds like a lot, but going by the bit of data I downloaded, the wholesale market paid $162m for electricity in Dec 2009 in Qld (maybe $1.5-1.9 billion per year?), and that's without a price on carbon.

    Anyway, those are the rather simplistic numbers I've just been crunching. Ignoring any alternatives, like demand reduction, efficiency gains, etc etc. Food for thought.
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  12. I have a couple problems with this ambitious plan that it will cost far more in the long run.

    Life of products to cost.
    What time frame will these need to be replaced due to age and structural breakdown. Also salt corrodes metal.

    Next storm damage. Is this taken into account?

    Technology needs to be far cheaper to be viable or whoever puts this in place will be booted out of office when it collapse and cost even more to replace with something else.
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  13. 12 Joe: "next storm damage"...

    Worth noting: Japan’s wind farms save its ass while nuclear plants founder
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  14. 13 les,

    Good thing there was a little wind, eh?
    Considering how terrible that technology is that it needs a great deal of subsidizing for governments to buy them.
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  15. Lalonde #12

    I'm not familiar with the details of the project, but coal and nuclear powerstations have their own maintenance and depreciation costs too. It all has to be taken into account.
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  16. Of course, not to mention risk management...
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  17. 14 Joe "Considering how terrible that technology is that it needs a great deal of subsidizing for governments to buy them."

    indeed, that pretty well sums up the nuclear option.
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  18. Joe Lalonde - regarding your comment about salt corroding metal - I'd say that it's more like chloride salts corrode metal (chlorine ions do nasty stuff to steel). If you're talking about the molten salt heat storage, the salt in question is likely to be a nitrate salt, not a chloride salt, so corrosion isn't a major issue.

    W.r.t. storm damage - well, if we can accept the risk of storm damage to our homes & the thousands of commercial buildings around the country, then I think we can live with the risk of storm damage to the heliostats... In other words, they can be designed to withstand all but the most severe storms - and one of those would shut down a coal-fired plant just as easily.
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  19. Giles is a teacher? If I were an English composition teacher, I would have flunked him for writing post #3. He broke every rule in the book!

    Why, I would even have to modify the complaint I see others making: not only is he "shoving FF propaganda down our throats", he is doing it so badly, it only inspires revulsion for his claims.

    But now trying to get us back to the science of global warming/climate change: the CST technology Wight describes certainly does better on the storage problem then I was aware for for any solar thermal solution, but the article still gives too glowing a picture: click on the Scientific American link and you will discover that though the efficiency is impressively high, it can keep up the power output level for only 7.5 hours.

    Of course, for much of the year, the night is longer than 8 hours. And not all the world is as sunny as Central Spain or Australia.

    So it leaves me wondering if one of the reasons the plan works so well for Australia -- even eliminating a need for nuclear-- is that Australia gets more sun than even the American SouthWest.

    But that's OK: we won't ask Australia to endorse the nuclear solution -- as long as you keep doing the uranium mining and selling it to the rest of us;)

    As for the corrosive potential of salts, yes, Bern, it is less corrosive than chlorides, but at that temperature, it it still corrosive. One should expect that there will be problems, hopefully tractable problems, discovered due to this corrosion as the technology gets more use.

    And yes, I am in favor of seeing it get more use.
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  20. I think asking "is it possible to decarbonise without relying on fossil fuels" is a good question that needs solid evidence. There are a lot of ideas - I was recently discussing the same point here - where there's an example of the opposite kind of knee-jerk reaction: "renewables without fossil fuels is impossible and we're all heading for mediaeval levels of per capita energy use." There was also some info on solar breeder plants, that try to tackle the problem head-on.

    But it seems to me we're some way from understanding the full range of issues in energy transition. So personally I'd lay off Gilles: it's a fair question, and one that I've not seen any completely convincing framework for answering.
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  21. Now concerning "society mobilized by ambition vision": yes, JFK did it. But let's not forget: young and even immature though he was, and despite his lamentable weakness for women of questionable reputations, JFK was a great leader. Somehow, for some mysterious reason, we just don't seem to produce such leaders any more.

    There is even a relatively famous book on this sad phenomenon: "Where Have All the Leaders Gone?" by Lee Iacocca.

    Nor is Iacocca the only one to comment on the problem. Bennis has an even more indicting title, "Why Leaders Can't Lead", and an endorsement from the legendary Peter Drucker. Then there are the famous Dilbert insights into the "mastodon dung" that passes for managers these days.

    The climate of the times has definitely changed since JFK. Instead of leaders rising to the top, our whole human society has started to look more and more like the sickening decay leading up to the Russian Revolution, when high-placed government ministers, instead of addressing real problems with probable solutions, would sequester themselves in occult meetings to try to conjure up the ghost of Rasputin (this really happened), at the same time, throwing roadblocks in the way of those precious few who really did try to solve problems.
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  22. MattJ #19 - the study addresses your CST overnight storage concern by noting that overnight demands are low. The 7.5 hour storage estimate is based on daytime power demands. The benefit of CST with storage is that output can easily be ramped down, unlike many traditional sources, which just waste the extra overnight production. Hence the "better than baseload" comment in the article.
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  23. How far above 350ppm does a total zero by 2020 get us?

    410-420ppm?

    "A windmill is made of steel (or carbon fibers) and concrete. How do you produce them without FF (and even dissociation of calcium carbonate produce CO2) ? electricity is transported by copper (or aluminium) wires : how do you produce them without FF ? how do you carry and erect the windmills without FF ? how do you travel across Australia without FF ? how do you power trucks, boats and planes ? how do you make isolators, paints, elastomers, fertilizers ?" (Gilles 2011)post 3.

    What is possible without FF and at a low carbon cost?
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  24. Bern @11, one factor that needs to be considered is the impact of clouds on domestic solar photo voltaic cells and solar hot water systems. We have the former at my house, and over the last few months in Brisbane, it has not been very effective. As domestic solar becomes more prevalent, increased cloud cover will see an increase in demand on mains power to run essentials like fridges and computers ;)
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  25. Moderators, could we have a thread about zero or low carbon alternatives to fossil fuels. Some of the alternatives here I have never heard of before, and it would be convenient to have a list with references in one location.

    Also, it would provide a place to send Gilles when he tries to derail a thread.
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  26. Rahul #23 - the plan is based on limiting warming to 2C, which is about 450 ppm, but only if every other major emitter follows suit.
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  27. Tom #25 - perhaps renewables can't provide baseload power?
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  28. Dana, I was thinking more in terms of alternative forms of concrete that do not release CO2 to the atmosphere as they set; or alternative transport solutions, such as solar powered derigibles instead of passenger ships, or modern automated sail for shipping. Somebody also mentioned non-fossil fuel based plastics and fertilizers. There are a large range of issues in decarbonizing an economy, but only power generation seems to get much discussion. A discussion of other options would be interesting (and very informative to me, so I'm not the one to write it).
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  29. @MattJ

    Well, Europe has ambitious plans for renewable energy, but I don't see any JFKs around there. We may not need a Superman to get this done.
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  30. MattJ @ 19: yes, the prototype / pilot plants constructed so far only had 7.5hrs of storage.

    However, in addition to demand being substantially lower at night (about 40% lower, according to the figures I downloaded), you have to look at how that 7.5hrs of storage is achieved - it's a big insulated tank full of molten salt.

    You want more storage? Build a bigger tank...
    Of course, that also requires an increase in the size of the collector to heat it up during the day, but it's not an intractable problem.
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  31. "if you understand that I'm claiming that it is not worth improving our energy efficiency and save FF, you totally misunderstand me. I'm sorry you're not able to get what I'm really saying - although as a teacher I am somewhat used to this kind of situation."

    Wow, you're a *teacher*? I really pity your students is all I can say. Every single post you extol the virtues of fossil fuels & tell everyone how civilization can't exist without them. You constantly assert-or at best imply-that energy efficiency is a worthless endeavour-so I'm not sure what there is to misunderstand? Maybe if you want to be better understood, you need to be a more effective communicator of what your actual views are on this subject, because so far you've done an exceptional job of portraying yourself as an unreconstructed supporter of all things fossil fuel.
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  32. "However, in addition to demand being substantially lower at night (about 40% lower, according to the figures I downloaded), you have to look at how that 7.5hrs of storage is achieved - it's a big insulated tank full of molten salt."

    A couple of points Bern. Firstly, if the majority of our street lights were solar powered (i.e. powered by batteries charged by sunlight during the day) & if owners of office buildings didn't feel the need to leave the whole office block lit up like a Christmas Tree, then I reckon night-time demand for mains electricity could be cut to little more than 20% of day-time peak demand. Secondly, Molten Storage is great, but I'm surprised there isn't more work going into so-called "Thermo-chemical storage". A number of ubiquitous chemicals-like Methane, sulfur trioxide, ammonia & apparently even water-can be broken down into their constituent components at the temperatures achieved by Concentrated Solar Power (though its true that some require a catalyst as well). Methane can be broken down to CO2 & H2, Sulfur Trioxide can be broken down to SO2 & O2, ammonia can be broken down into N2 & H2 & even water can (with a nickel catalyst) apparently be broken down into H2 & O2. Now, once broken down, the energy can be retained as long as you want, until you re-react them together again-which will, of course, re-release the heat as an exothermic reaction. Not only does it represent an excellent source of long-term storage of solar heat for night time & very cloudy days, but some of the by-products can even be used as feedstock for other industrial processes. Just a thought.
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  33. "I was in iceland last year. I saw a BP hydrogen station in Reykjavik (actually I think there are a few of them). Very nice green paints. Unfortunately, not a single car stopping at them. May be some buses stop there from time to time , but I missed the time;"

    Yes, & how old is this technology Gilles? From my reading its barely been around more than 5 or 6 years. Sheesh, I reckon if I went back in time about 120 years, I'd be able to gleefully "predict" that petroleum & Internal Combustion Engines were a total dead end-because there would have been no petroleum distribution network yet & very few people making use of what little petroleum dispensing centers currently existed at that time. We all know how useful that little prediction would be though, wouldn't we? This highlights how pointless *all* of your questions regarding *current* use of renewable fuels actually is. It doesn't *matter* what the current situation is, as the technology is still relatively new-only the future potential of the technology is what matters. Coal & Oil were, in their beginnings, the only real game in town, yet they took several *decades*, even with 100% government support, to go from the drawing boards to commercial viability-& even today these industries enjoy very healthy subsidies courtesy of tax payers. Yet people like you frequently *demand* that renewable energy technologies be 100% commercially viable, subsidy free, *yesterday*.
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  34. Tom @28. I've read about a number of low-carbon building techniques over the years-in a purely amateur fashion of course. Like I said, the Romans made their cement out of Aluminium Silicate-which was to be found in abundance on at areas of high volcanic activity. Ironically, fly-ash waste from burning coal is also a rich source of aluminium silicate as well (& there must be *billions* of tonnes of the stuff buried around the world after at least 30 years of the stuff being collected in flue stacks, rather than released into the atmosphere). Anyway, the stuff we've been using since the 19th century makes use of Calcium Carbonate which, when baked at high temperature, releases CO2 & leaves behind Calcium Oxide-which is what they actually use to make the cement. Aluminium Silicate, by contrast, releases no CO2 when it is made into cement-so is effectively CO2 free.
    Another area is steel manufacture. It's just common sense that steel containing a large amount of material from recycled material will require less energy to manufacture than making it from raw iron ore. Arc Furnaces are also more efficient than blast furnaces, requiring just 1/3rd of the energy to melt iron & steel than blast furnaces. Also, I've read of attempts by the some steel manufacturers to capture the waste heat from making steel, & converting it into electricity (so-called co-generation). All combined, this could make the manufacture of renewable energy generation systems much less CO2 intensive.
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  35. Thanks
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  36. I think there's something we need to ask in relation to the title of this post-how are we defining "Zero Carbon"? I mean, are we talking net zero CO2 (i.e. where the amount of CO2 put out is at least matched by the CO2 soaked up by new & existing sinks), gross zero CO2 (i.e. no CO2 emitted from Human Sources at all), or net/gross CO2e (i.e. where the amount of *actual* CO2 produced is offset by a reduction in the production of other, worse, greenhouse gases). If its defined as net CO2e, then I think Bio-gas is an oft overlooked option for base-load energy production. After all, human waste streams are *always* going to produce methane, which is an 8 times worse GHG than CO2. So every tonne of methane converted to a tonne of CO2 means 7 tonnes of CO2e effectively saved (at least as I understand it). Also, every tonne of CO2 produced from burning bio-gas to generate around 2 MW-h of electricity saves around 2t of CO2 produced by burning coal to generate the same amount of electricity. So, unless I misunderstand it, burning 1t of methane to generate around 2 MW-h of electricity saves approximately 9t CO2e. Of course, this benefit can be extended further by (a) using any waste heat to heat local buildings or heat for industrial uses & (b) if the bulk of the CO2 gets captured in algal biomass, which can then be gasified & re-used to produce electricity/heat. Anyway, just a thought.
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  37. While I appreciate the optimism and logic you display in your article, from what I can see going on politically in the U.S. and elsewhere, I think the momentum for making serious changes has slowed to a near stand-still and in some respects reversed. To make the kinds of changes you suggest will require a different mind-set of the majority of citizens-- something akin to a "war footing" and that is not currently in place. It will only be to the extent that climate change related "inconveniences" impact the lives of the average person that they get a war-footing mentality and support the kinds of changes suggested. In short, even if the majority of politicians were behind what you suggest (which they aren't), they'd still need to convince the majority of voters to go along with these changes as their will be the upfront costs.
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  38. Marcus - yes, you're right, there are many options out there for energy storage. I understand it's a rich field of research at the moment.

    The molten salt option was chosen by ZCA, as I understand it, because it's easy, proven, and off-the-shelf. It's also all you need if you only want to provide storage for ~12-15 hours or so.

    I do like the "long term storage" that some of the chemical options give you, very much worth looking in to.

    Oh, re methane - as I understand it, it's 77 times worse than CO2 over 20 years, and 25 times worse over a century. So biogas is an even better option than you state (and is why landfill gas projects are sometimes considered to be greenhouse negative).

    R.Gates - yes, the political will needs to be there. I was going to comment further on that, but it's seriously off-topic for this thread, which I think is focussing more on the technical side of things.
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  39. R. Gates #37

    Well, I understand the point of publishing such a study is try to raise public interest and political will via showing the possibilities.
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  40. Original Post

    Has James considered the situation of a large weather system such as has deluged Queensland this summer where heavy cloud and rain persist for several days (up to a week or more) - and there is much reduced solar and not much wind.

    The molten salt would not cover more than 12-15 hours storage.

    Looking at the map - 4 or 5 power towers and some of the wind would not be producing much at all.

    What would be available to avoid power cuts and disruption to nearly all our work and domestic life?
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  41. Hi all,

    I have a bit of a gripe against wind turbines.

    In your article, John, you say at one point "...zero-carbon, not counting emissions from construction."...

    Well, a couple of points of information, of dubious accuarcy, as I quote from a fallible memory:

    1. About 5% of all anthropogenic CO2 is generated by cement production.

    2. So much cement goes into a wind turbine that it takes 30 years to save the equivalent in CO2 emissions.

    I also strongly suspect that there is something to be learned from our forefathers here. Windmills were historically only ever widely built where there was absolutely no other choice, in areas such as Holland and the English Fens.

    Wherever anybody ever had a choice between building a watermill or a windmill, you see very few windmills.

    Now, I'm not at all sure that fluvial water power would be adequate to supply Oz's power needs, though it would be more reliable than wind, where available. But there might be a good deal of point you lot keeping a very close eye on the latest developments in tidal and otherwise maritime power generation.

    The latest scheme I heard of is to supply the Island of Islay in Scotland with all of its household power needs, and enough to run 8 single malt distilleries, entirely from submerged marine generators of some kind.

    Given that loads of Ozzies seem to have settled along the coasts, so you can practice surfing and being bad at cricket, and that the Roaring Forties of the Southern Ocean aren't that far away...

    Anyway, I'm no expert, and unlikely to be one any time soon, but just thought I'd say.

    Also, I only just came across this yesterday, and haven't looked into it at all, but I have seem it claimed that thorium is the magic bullet. Safe nuclear. Hmmmmmmmm...

    P.S. Anybody wishing to encourage Islay in its efforts to go carbon zero can probably find a most enjoyable way to express your appreciation in the most expensive section of the drinks aisle.
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  42. Idunno: 1. About 5% of all anthropogenic CO2 is generated by cement production.

    2. So much cement goes into a wind turbine that it takes 30 years to save the equivalent in CO2 emissions.


    But how much of total cement production is used to construct wind turbines?
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  43. Hi RickG,

    Sorry, absolutely no idea.
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  44. idunno:

    CO2 emissions from fossil fuel power generation:


    Pollutant CO2 (Tonnes/GJ)
    Hard coal 0.0946
    Brown coal 0.101
    Fuel oil 0.0774
    Other oil 0.0741
    Gas 0.0561

    The average CO2 intensity ranges from 0.65 to 0.92 tonne of CO2 per tonne of cement across countries with a weighted average 0.83 t CO2 /t. The global average CO2 intensity in cement production declined by 1% per year between 1994 and 2003.


    Around 150 tonnes of concrete are used in the foundations of a single wind turbine.


    So, in the least efficient case, when we substitute wind for gas power generation, the cement in the wind power station would produce the same amount of CO2 as the Gas power station would produce after producing 2,460 GJoules. So, over 30 years, and assuming no power production due to maintenance for two days in every 7, the wind turbine would have to produce all of 3,650 Watts on average during operational times. For a 1.5 MW wind turbine, that represents an efficiency of 0.24%.

    Somebody was feeding you a furphy.

    And just a minor point, how much cement do you think there is in a gas fired power station?
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  45. idunno, further to your 41:

    Fluvial water power could not supply even a very small fraction of Australia's power needs. Hydroelectric power, on the other hand, already supplies a significant amount, but opportunities for new stations are limited.

    On the other hand, I personally believe that wave power is the way forward for much of Australia's renewable power needs. It is, however, an undeveloped technology and is unlikely to be readily available by 2020. (2040 is a bit different.)

    Finally, I have seen a number of people pushing Thorium as a magic bullet for nuclear safety. I have seen exactly the same people come out on mass a few days ago to declare that the problems at Fukujima power station were very minor and would not lead to significant exposure to radiation for anyone. That, in fact, the event was a squib and wouldn't even rate with Three Mile Island. Jokes were made comparing the expected radiation exposures from the event to those experienced from eating a banana (which are very slightly radioactive because of their phosphorous content).

    I take it with a grain of salt, or perhaps a grain of iodine.
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  46. Rahul #23 - the plan is based on limiting warming to 2C, which is about 450 ppm, but only if every other major emitter follows suit.

    Dana but isn't that wishful thinking, that 450ppm is 2C, when the pliocene was 3-5C warmer at 350ppm?

    Basically 450ppm means we won't even be able to adapt!
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  47. Further to my 44, at a reasonable efficiency (35%), the CO2 from the concrete foundation would be fully compensated for after 75 days. Of course, I have assumed that the foundations are entirely cement, whereas concrete consists mostly of steal and gravel, much reducing that figure. Also, some turbines require up to 800 tonnes of concrete for their foundations, increasing the time required by a factor of five. All in all, three months is about the top time that should be required.
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  48. @energy storage
    I would like to draw your attention to the interesting storage technology from the British startup called Isentropic.
    They store electric energy as a heat, claiming 80% accuracy of energy recovery. They use two storage tanks filled with gravel. One is heated to 500C and the other cooled to -150C, with the argon that is heated and cooled by heat pumps powered by electricity. Then, when the electricity is needed the heat pump works as generator recovering energy from the gravel.
    As far as I know they have built two small scale prototypes, working according to specs.
    They claim the storage costs between $55 and $10 per kWh, the latter for a large scale installations, which quite impressive.
    Certainly it could be very interesting alternative to the molten salt heat storage.
    Their web page.
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  49. Hi several people,

    I retract. I had assumed that most of the pylon of a wind-generator was also concrete. If anybody else has published correct info, ignore that bit of my comment #41.

    I still do think there may be more potential in water-driven generation, specifically subsurface marine and/or tidal.

    As I say, I have really no idea if the claims made for thorium are credible.

    About the whisky and the cricket though, ;p
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  50. ranyl #46, keep in mind that the current CO2 level is 'artificially inflated' in the sense that it represents an overflow rather than equilibrium value. Basically, about half the CO2 we emit each year is currently being sequestered (mostly in the oceans). If we were to drop to zero emissions that sequestration would continue and the atmospheric concentration would start dropping... probably at a rate of about 2 ppm per year.

    Thus, even if we hit 450 ppm before zero emissions goes into effect, we would not stay at that level once emissions stopped.

    As to 2C vs 3-5C... the difference is between fast feedbacks and slow feedbacks. A doubling of CO2 (about 560 ppm) will likely cause about 3C warming from fast feedbacks (i.e. within a few decades), but more likely around 6C when slow feedbacks (i.e. within a couple of centuries) are considered. However, both of those would require that the atmospheric CO2 level remain elevated... which it would not if our emissions drop significantly below the rate at which atmospheric CO2 can be sequestered.
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