Arguments
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.
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.
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?
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.
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?
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...
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.
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 ?
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.
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!
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.
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.
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.
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.
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.
Worth noting: Japan’s wind farms save its ass while nuclear plants founder
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.
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.
indeed, that pretty well sums up the nuclear option.
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.
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.
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.
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.
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?
Also, it would provide a place to send Gilles when he tries to derail a thread.
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.
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.
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.
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.
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*.
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.
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.
Well, I understand the point of publishing such a study is try to raise public interest and political will via showing the possibilities.
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?
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.
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?
Sorry, absolutely no idea.
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
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?
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.
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!
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.
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
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.