On Monday afternoon I was driving south towards Seville on the motorway when I saw two bright lights just above the hazy horizon of the Guadalquivir plain to my right. I’ve a poor snapshot to prove it (at the end). They were reflections from the collectors of the two solar power towers at Sanlúcar la Mayor: twelve miles away. Wow.
The anecdote has no bearing on the rational case for solar thermal technology. Power towers may or may not be a better choice than parabolic trough, linear Fresnel, or Stirling-dish designs; and solar thermal may itself be bypassed by some breakthrough in photovoltaics. But it does speak to the irrational component of attitudes to technology. Some of the objection to renewable green energy is from machismo: rooftop windmills and solar-powered lights are small, intermittent, toylike, in short girly. Real technology is big, strong, reliable machinery at high temperatures and pressures. It’s easy, as I’m doing. to poke fun at the engineering romanticism of men – I think it’s always men – who yield to temptation in hardware stores and buy 50-piece socket wrench sets. (I have one gathering cobwebs in my cellar too.) But the boy’s romance with good tools is surely important to many scientists, engineers and skilled workers, and it’s connected with their pride in doing a good job. Kipling’s Scots ship’s engineer McAndrew gives this a religious turn:
From coupler-flange to spindle-guide I see Thy Hand, O God –
Predestination in the stride o’ yon connectin’-rod.
John Calvin might ha’ forged the same – enorrmous, certain, slow –
Ay, wrought it in the furnace-flame – my “Institutio.”
There’s a grain of truth in Shelley’s boast that “poets are the unacknowledged legislators of the world”, and the lives of scientists and engineers are in part the fulfilment of childhood dreams.
In this powerful romantic aesthetic, the ideal energy technology is fusion: temperatures of half a billion degrees, superstrong magnets or lasers, an exotic (but not incomprehensible) scientific basis, and a bit of danger. But it’s nowhere near a workable energy supply. Solar power towers are not bad runners-up, and we can have them tomorrow. A research solar furnace can routinely create temperatures up to 3,500°C in a pan-sized target, enough to melt pretty much every elemental material but diamond. For a power tower, you want a lower temperature over a much bigger area. The Sanlúcar power towers use a conservative design of collector, 14 metres wide, to generate steam at 250°C and 40 bar. This is quite enough to drive a standard steam turbine. The next step up has so far been taken in small demonstration setups: to heat air to 1000°C or so in a ceramic exchanger to drive a gas turbine directly. The beauty here is that you can combine the solar generator with fossil gas at night. And the technology (in whatever version) lends itself to grandiose plans to cover the Sahara with solar generators and ship the electricity to Europe.
Source: DESERTEC, via Wikipedia
The holy grail here isn’t really power generation – we know this works, it’s a matter of settling on the best technology and bringing costs down – but cement: 1.8 billion tonnes a year of it, made in kilns at 1450°C. The process generates a startling 5% of the world’s carbon emissions, comparable to those of steelmaking. Why not use the sun to calcine the limestone? This has been demonstrated on the kilogramme scale, and in a continuous process, by Bonaldi and Meier in a Swiss laboratory linked to Einstein’s ETH. I couldn’t find any evidence of a bigger pilot plant.
If I had money to spend on long-term, high-risk, high-payoff green research, I’d put a lot into solar cementmaking. For real men, and the boys inside them. You could build huge solar cement works in the remaining expanses of the Sahara and ship the powder out in bulk carriers drawn by giant kites …
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Promised bad snapshot, blown up by 2:
James,
About half the CO2 emissions from cement-making are intrinsic to the process: the calcium starts off as calcium carbonate and loses a molecule of CO2 for each atom of calcium. It's still worth removing the other half of the carbon emissions, of course, but the process isn't going to be carbon-neutral, or even close.
You realize that much of the CO2 emitted is from the limestone itself, not just the power supplied to do the work, right?
If we are to increase our (already dim and fast-dwindling) chances of avoiding climate chaos, we will need the kind of radical decarbonization that it appears that even "greens" cannot bring themselves to contemplate … like no more cement for use in rich countries, pretty much no more jet air travel, rapid shutdown of all coal use, no more grains fed to animals (meaning a steep decline in meat production), etc.
See "The End of the Long Summer"
http://www.powells.com/biblio/9780307396075?&…
See "Climate Chaos"
http://www.powells.com/biblio/71-9780275998585-0
See "Now or Never"
http://www.powells.com/biblio/2-9780802118981-1
Thanks Thomas for making one of two very important points. Yes, regardless of energy source Portland Cement is emission intensive. However there are alternative cements such as GranCrete that are not based upon limestone. http://www.grancrete.net/. (only one example.) Incidentally, emissions from cement are large but nowhere near that of electricity production.
At some point the cure becomes worse than the illness.
What is all that cement being used for? Anybody know?
cutting CO2 emissions from cement making in half is still a big chunk. What the price on Carbon would have to be to make it possible, no clue.
Naturally, limestone is one of the greatest carbon sinks other than coal I imagine.
The chemical release of carbon from calcination is true (CaCO3 + heat -> CaO + CO2) but so what? The oil or gas needed for the heating, 2½% of world carbon emissions, is still a very big target. I assume that carbon sequestration from cement works is not much different than from fossil fuel power stations, and a lot of effort is going into that already.
JMG: please think about the five wedges. Some steps towards carbon neutrality are technically quite easy: insulating and properly thermostatting buildings, stopping deforestation, shifting electricity production to renewables. Others are difficult, like fixing aviation and cement. But Bonaldi and Meier have shown us that zero-carbon cement is possible, with a solar furnace plus sequestration. This is worth knowing, and worth encouraging with public money.
The myth or legend of Noah's Ark contains an important truth. The survivors of disasters are not those who pretend it's not happening till too late, or those who panic and run round in despair, sacrificing virgins and whatnot. Survivors come from those who get started with a rational plan using the resources available. Doesn't always work of course, but it's the only way to go.
"Some of the objection to renewable green energy is from machismo: rooftop windmills and solar-powered lights are small, intermittent, toylike, in short girly."
I'd hardly call objections to intermittent power sources "machismo". They're just objectively undesirable.
Cement from CO2: A Concrete Cure for Global Warming?: A new technique could turn cement from a source of climate changing greenhouse gases into a way to remove them from the air
Brett: are intermittent food crops objectively undesirable? is skiing objectively undesirable because you can only do it it in winter? Abundant, sustainable, fixed-cost, intermittent, energy sources are far more desirable than operationally reliable, environment-destroying, politically insecure, unhealthy, price-volatile, and increasingly scarce energy sources. Much of our current electricity consumption can be time-shifted or temporarily abated at minimal inconvenience, with obvious technical fixes like smart meters. I maintain that your objectivity is an aesthetic preference.
CharlesWT: according to your link, the Calera process sequesters CO2 (good) by bubbling CO2-rich flue gas through seawater to make calcium carbonate – chalk, limestone, coral, the raw material for cement. Surely it's a misnomer to describe the product as itself a cement, rather than something you can put into concrete harmlessly with real cement? If that's so, then the process is unlikely to reduce the need for the latter very much. I own a house in Brighton built in the 1870s out of practically cement-free "bungarouche", and it's not a building material I trust. Expert input welcome.
Ah. Calera's product is a "supplementary cementitious material", a pozzolan which reacts with Portland cement to add additional binding. So their claim to reduce the need for Portland cement is not fanciful. The dome of the Pantheon in Rome was made out of a pozzolanic, pre-Portland concrete and it's lasted 1900 years.
Let a hundred flowers bloom.
Yes, James, intermittency is an undesirable trait in a power source. Unpredictable intermittency even more so. It's no use pretending that a preference for reliable, constant sources of power is an irrational prejudice, all you'll do is come across as silly.
Seawater is a rather dilute source of calcium and magnesium, maybe the Calera people have some exceedingly cleaver breakthrough, but it's not at all obvious that it's practical. Believe it when we see it.
intermittency is an undesirable trait – and so is dumping CO2 into the atmosphere.
so perhaps intermittency on a source level can be leveled out with a dynamic continent wide grid?
We have to work around the bad traits we can, and avoid the ones we can't. CO2 is very, very hard to avoid for coal.
Ok, so what about Autoclaved Aerated Concrete?
Intermitent power sources become viable with a storage system. In Denmark (where they are making and using wind generators like there is a tomorrow) the government (imagine) is developing a plan to set up a network to plug electric cars into the grid using inactive car batteries as a national storage system. Car owners buy power when it's cheap and sell it back when it's expensive. It is even concievable that entrepreneurs could own storage batteries for the sole purpose of buying and selling power.
Of course a system like that requires a lot of people to drive electric cars so the government needs to be very proactive in ecouraging and enabling people to buy electric cars. I can hear the cries of outrage from the right declaring it far better to destroy the planet than to let big government interfere in the free market. Besides who wants cheap, clean energy? How whould Haliburton, Blackwater and BP make money then?
What is up with all the plans to send electricity from Sahara to Europe? Isn't the need for more power far greater in Africa? I think we are repeating some rather unfortunate history if we don't plan for running at least some of those power lines south as well as north.
Brett: "intermittency is an undesirable trait in a power source." By itself, yes. But I do think it's irrational to raise this to a lexical priority rather than one of a set of technical, economic, environmental and social features which have to be evaluated as a whole, and in the context of a complete energy supply system including feasible workarounds. My point was really about the stereotypes that people inevitably bring to the table, before the rational analysis begins: which sometimes prevent them from listening to it, and always colours what they take away.
Mattias: the Desertec paper exercise does talk about covering the energy needs of North Africa and the Middle East as well as that of Europe with a pharaonic $400bn green supergrid. They write (p.38) that "the solar energy resource in MENA [Middle East and North Africa] is about a hundred times larger than demand will ever be." Desertec is a policy lobby rather than a project consortium, though it has backing from Siemens and other heavy German players. The group is involved in a project to build a solar plant in oil-less Morocco, and Tunisia (on the strait to Sicily) is also supportive. The concept looks doable rather than nutty; on what scale it will be realized depends on the opaque and authoritarian politics of Algeria, Libya and Egypt as much as anything.
Desertec don't say anything about sub-Saharan Africa. It would a priori be pointless to transmit power from one side of the Sahara to the other. The Sahel countries – Mauretania, Mali, Chad, Sudan – have lots of sun themselves, and are just about the poorest club in the world, with a tiny current demand for electricity. They could export it south to the richer and more populous coast under some other hopeful megaplan.
Brett Bellmore says:
"Yes, James, intermittency is an undesirable trait in a power source. Unpredictable intermittency even more so. It’s no use pretending that a preference for reliable, constant sources of power is an irrational prejudice, all you’ll do is come across as silly."
He's not. He's pointing out that there are other factors involved.
(Hmmmmm. I wonder what Brett would do if I said that CO2 was an Islamo-Euro-femi-nazi plot?
We've already seen Mr. Libertarian become Mr. IftheIsraeliGovernmentBeatsYouThenYouDeserveIt, with a second helping of cheering government repression).
Your basic point about the male tendency to get mired in the edifice complex is a good one — and you have illustrated it perfectly yourself!
You have a suggestion for a techno wondertoy that will somehow enable us to keep using more and more energy and materials and a duex ex machina that you can add to the end of any process (carbon sequestration) to make it appear carbon negative.
Lovelock is right — between the right-wing idiots in denial about climate disruption and the lefty idiots in denial about pace of that disruption and the scale of the changes that would be required to address it, we're not going to do anything meaningful. As Flannery suggests, it's now or never, and it appears increasingly likely to be never.
JMG, it's not the 'new jesus' – it's just one more small step, of which we need hundreds.
Despair is not a road to travel today, and neither is denial.
"Hmmmmm. I wonder what Brett would do if I said that CO2 was an Islamo-Euro-femi-nazi plot?"
Probably suggest that you find a psychiatrist. How can a chemical be a plot? It's not even the sort of thing that COULD be a plot…
I realize there are other factors involved. I also realize that, under most circumstances, and presently, energy storage is so expensive that any source of energy which isn't available 24/7 is almost guaranteed to be uneconomic. Certainly, all else being equal, we don't want our energy sources to be intermittent, and even less so random.
The grid already deals with randomness in electricity usage – whether I run my dishwasher today or tomorrow.
Solar and wind availability is somewhat random, but on a different scale. Ie, San Francisco is foggy this morning, so none of the solar is going to do much good. But 10 miles east….
But yes, intermittentcy is a big problem requiring tech, money, work, and change to our habits even. Letting CO2 rise to dangerous levels is also uneconimic, and in a way that is harder to fix once it's there. So I'll try to solve the easier problem.