Heliophage

Not that it’s really very likely, but I’m sure those who disagree with David Attenborough will be on to it. According to Earth2Tech it’s a Vestas windmill in Denmark, in a gale, with faulty brakes. The government is investigating.

Upside — as ecogeek points out, this is a pretty good counterargument to people who think there’s not much energy in wind.

Downside — pretty obvious.

Meanwhile, brownouts in Texas. No technology is perfect…

And also via EnvironmentalCapital, a rather neat map of global wind and solar resources

Update: the original version of the video, http://www.youtube.com/watch?v=lvvRHhsQhi8, vanished so I’ve put up another one.

Despite the urgent need to publicise my appearance at the Brighton Science Festival’s Big Science Sunday, I wasn’t planning another South Downs conservation post, but synchronicity forced my hand. Shortly before leaving work tonight, I was irritating my colleagues by voicing my probably irrational dislike for programming by David Attenborough. (It has at least vague justifications — I particularly dislike the way that he sees wonder as immanent in nature itself, rather than a creation of the way in which we position ourselves with respect to nature — but this is probably not the place for them, and honesty compels me to admit there may be a bunch of things like grandfather hang-ups at play too).

Anyway, having just fulminated over-expressively I pick up a newspaper on the train taking me home and read of the great man himself doing something very impressive: trying to talk a bunch of Sussex nimbys in my sometime hometown of Lewes out of their opposition to a largish windmill proposed for the Glyndebourne opera house. Quoth Sir David:

“I greatly applaud the plan to erect a wind turbine. That such a celebrated institution should pay such regard to its environmental responsibilities seemed to me to be wholly admirable, demonstrating that some communities really do take the ecological challenge seriously and do not simply utter pious words and leave it to others to take action.

“A wind turbine, with its graceful lines, collecting energy from the environment without causing any material damage, is a marvellous demonstration of the way we can minimise our pollution of the atmosphere if we wish to do so. It would help protect not only the countryside we have known for centuries but also the wider world beyond.”

I don’t think one windmill in Sussex makes much of a difference either way — wind’s role in the UK will surely be mainly off shore. And a windmill for an establishment that also maintains a helipad is a trifle absurd. But such things do have symbolic power, especially when coupled with a cultural attraction of such excellence and renown. And the arguments against windfarms — that they damage views that they often enhance, and that they, as interventions that will last a century at most, in some way do lasting damage to landscapes, rather than to the amenity they provide to those in the happy position of inhabiting those landscapes and unwilling to see them change — seem so wrong headed that I find myself broadly in favour of the things on principle. Besides, I like the energy-as-flow symbolism that they embody so gracefully; look at a wind turbie and you know that your seeing an open process, not a finite stock, and that’s a good lesson in how we have to understand energy in the decades to come.

In the grand-old-man stakes it seems odd to find myself on the same side as Attenborough, whose work I mainly dislike, and the opposite side to Jim Lovelock, whose work I deeply respect. But attitudes to the countryside do funny things to us all.

Picture from near Glyndbourne under a creative commons licence from SussexWalkabout

A bit of climate politics, cross posted from Climate Feedback

He also points out that Lieberman-Warner gives away a lot of free permits — “an idea that leaves some environmentalists tearing their hair out” — while Clinton and Obama are talking about auctioning all the permits from day one. The auction approach makes sense both in terms of justice and I think in terms of policy. Whether it makes sense in terms of politics is not so clear. The European Commission, which takes these things seriously, has so far not managed to engineer a consensus on auctioning all permits (though it may get to it sometime in the mid teens). If an incoming president were able actually to set up the sort of aggressive (in a good way) cap and trade system Obama and Clinton are talking about that would be quite something, and it might well encourage the Europeans to go further. Whether it is politically possible in an economy that may well then be in or recovering from recession has to be open to doubt.

What isn’t open to doubt is that it would require a massive investment of the new president’s political capital. One implication there is that if climate is key to your vote, you’ll be best off voting for the Democrat who you expect to have the longer coat-tails, and thus to end up with more and more grateful partisan support on the HIll. But bear in mind that while in the senate, neither Clinton nor Obama have championed climate change in a particularly noticeable way, while McCain has invested quite a lot in it, and did so against the predilections of his party. So I can’t help thinking that any climate legislation that does come through under a Democratic president may end up a fair bit closer to Lieberman-Warner than to the more dramatic stances currently under offer. Happy to be argued out of this stance, or indeed proved wrong.

Which is not to say there are no distinctions to be drawn. Interestingly, Chris doesn’t say much about energy policy, as opposed to emissions goals. Checking out the Popular Mechanics really kinda wonderful Geek the Vote site shows that both the dems have a lot to say about the energy side of the equation, McCain rather less so. The site (which I got sent to by an earlier post of Chris’s) lists 17 Clinton policy ideas in climate/energy/environment areas, 40 (!) from Obama, and one from McCain. Here’s Obama’s energy page, and here’s Clinton’s.

It seems to me that if you want to find a difference between the candidates on this issue, the amount of thought and talk they are putting into smart energy investment (which is something that will be a lot easier for a new president to make progress on than charging politically powerful industries for their carbon emissions) may be a more revealing way of making the distinction than their stated policies for emissions on the 2050 timescale.

Of course Chris would say that if you want to find a difference you should arrange a debate. But opinions differ about that…

(Incidentally, those of you with a subscription to New Scientist should check out Chris’s rave review of Gabrielle Walker and David King’s The Hot Topic.)

Image from Mike Licht, NotionsCapital.com under a Creative Commons licence

When, a while ago, I was thinking of a slogan for solar power enthusiasts, perhaps to be used as the title of a blog, what I came up with was “Two terawatts by 2020″. I never started the blog — ignoring this one and the other one takes up pretty much all my blogging time — but the slogan sort of stayed with me.

The idea was that we now run a +/-13TW civilization; that’s the amount of power we generate and use. If we want people in developing countries to live as well as Europeans or the Japanese, and assume that they need to be in the same ballpark in terms of energy use to do so (a questionable assumption, admittedly — but better than assuming it can be done with less energy and finding we’re wrong) then on current figures we need to get to around 40-50TW by mid century. That’s a fairly high end assumption, but I’m fairly pro development.

If we want to get to that sort of energy use without aggravating the carbon/climate crisis unbearably, then 80% or so of that generating target needs to be carbon neutral, with the trend continuing on towards 100%.

With this in mind two terawatts of installed solar capacity by 2020 seemed to me to be a pretty good intermediate target. It would represent 10% or more of total energy use at that point, and form a nice gateway to 35TW of solar or so in 2050. (From 2TW to 35TW in 30 years represents a reasonably staid annual growth rate of 10%).

To get up to 2TW in 2020, though, requires pretty dramatic growth between now and then; today’s installed solar capacity is less than 1% of that. The nice news embodied in the graph at the top of this entry is that, if things follow the trend of the past few years, then that sort of growth is not inconceivable. The Earth Policy Institute’s solar economy figures (via Jim at the Energy Blog), represented in the graph above that demonstrates such a pleasing trend to the perpendicular, say that in 2007 solar cell production rose 50%, producing cells with a total capacity of 3.8 gigawatts. If the 50% annual growth could be kept up, by 2022 we would be adding a terawatt of new capacity a year — and our installed capacity would by that point be more than 2TW, since solar cells stick around. If new growth in our capacity to produce solar cells simply stopped right then then adding a steady terawatt a year would still give us 30TW of capacity by 2050 as long as the cells in question lasted for decades.

None of which is to say that this will necessarily happen. By and large, betting on exponential growth continuing is never very wise in a finite world. But the world is not, in all respects, finite — or rather, its finitude expands. As Moore’s law reveals, technologies can maintain exponential growth over decades if the economic setting is sufficiently expansive, both in terms of the growth of the economy and the growth of demand. As I mention in passing in the book, the x-rays available for scientific research double in “brilliance”, a technical measure of how good the beam is, every 15 months, and have been doing so for some time (see chart here).

In the case of X-rays the expansive economic setting is a willingness to pay on the part of research funders (which is not unproblematic — a willingness to pay for the UK’s very brilliant new X-ray source Diamond is being linked to an unwillingness to pay for work in astronomy and particle physics, to widespread discontent in those communities). In solar cell terms, the growth in use is closely linked to subsidies; that is why Germany leads the world in new installations. In 2006 it became the first country to install a gigawatt of solar capacity in a year. (That doesn’t mean Germany generated a solar gigawatt — night and clouds and winter eat into the capacity. But that lack of availability is a constant term and as long as we’re talking about exponential growth at this sort of rate we can in effect ignore it.)

At subsidy levels of a few dollars a watt the difference between supporting a gigawatt of use and a terawatt of use is fairly noticeable. Subsidies in the trillion-dollar-a-year-range would be hellishly large even by agricultural or military-industrial-complex standards.

That’s why this chart is a crucial one.

The worrying thing you’ll notice is that on this one the rate at which costs were falling flattened out at pretty much the same time that the first graph shows production capacity starting to leap. I have no idea why this is, or indeed if it’s a real effect or some sort of artefact of combining different data sources. Off the top of my head, one possibility is that it was around that time that the bulk price of silicon started to dominate total costs. Another is that it was about that point that subsidies started to take off, reducing interest in cutting costs (I rather doubt that one) [see update, below]. Another is that it was around this point that the costs of the module you put the cells in became an appreciable factor in total cost, and module costs are less easy to cut than cell costs. If anyone who actually knows about this stuff could weigh in, I’d be most appreciative.

Leaving aside the strange inflection, though, the chart still trends down. It doesn’t do so strongly enough to justify the industry rule of thumb that you can expect a 20% drop in production costs every time capacity doubles, at least not to my eye, but maybe that rule is for cells not modules. If that rule does still hold, them by my rough calculations you’d expect 50% growth in production year on year to reduce costs by 50% every five years or so, with costs dropping to 20% of today’s costs by 2020. That would be comfortably below the subsidy level, I think.

Anyway, I’m not sure I trust that old rule of thumb in a world of new markets and new technologies. I can imagine costs falling quicker with the advent of continuously processed thin films; with systems optimised for integration into new buildings; and with a lot of the sort entrepreneurialism and technological innovation of the sort found in Silicon Valley (and elsewhere). I wrote a feature about this for Nature in 2006, a piece which, thanks to kind sponsorship, is available here for free. Excerpt:

Amid all the cleantech opportunities, photovoltaics seem to resonate most with Silicon Valley’s history and culture.

One attraction is technological familiarity. Solar power has grown up in the shadow of the chip industry, using its cast-off materials and technologies. The silicon in traditional solar cells comes from the same suppliers who feed the chip market; new techniques to make solar cells often use processing technology, such as chemical vapour deposition, that is already widely used in the production of integrated circuits. Miasolé, a Silicon Valley solar start-up in which Kleiner Perkins has invested, uses expertise derived from the manufacture of computer hard drives.

But there is a broader cultural attraction, too. The potential of solar power to decentralize energy generation — a potential shared, to a lesser extent, by wind power — appeals to a culture that places huge societal significance on the empowering spread of the Internet. And a business community that saw personal computers go from hobbyists’ workshops to almost a billion of the world’s desks in 30 years is not fazed by the small size of the solar market today, but energized by the possibilities of tomorrow.

It’s also a help that Silicon Valley is sunny not just in its outlook; a solar cell in California can produce almost twice as much electricity a year as one in the Ruhr.

….

A decade’s growth, however buoyant, doesn’t by itself mean that much. That growth needs to last for several decades to change an economy, and needs to accelerate to an even higher level to change the world.

The difference between growing at a more than respectable 25% a year [a widely accepted forecast figure discussed in the article] and at 44% a year — the rate at which volume grew in 2005 — is the difference between doubling in size in just over three years and in just over two. That may not sound a great deal, but over 15 years it means something growing at 44% would outdo something growing at 25% by a factor of eight. Between now and 2050, the difference is a factor of 500. And that could be the difference between providing just 2% of Earth’s energy needs — and 10 times those needs.

The remarkable thing is that the products of the semiconductor industry have grown at a yet faster rate for a similar length of time. If Silicon Valley can apply Moore’s law to the capture of sunshine, it could change the world again.

The company that was a focus for that article, NanoSolar, has just started shipping its thin-film panels; another of the companies, HelioVolt, has just announced manufacturing plans of its own, having raised $100m in capital last year. (Interestingly the two are going in different directions. Nanosolar is targetting installations on sites dedicated to power generation on the outskirts of towns and cities, while heliovolt is intrested in integrating solar cells into construction materials for new buildings.)

But while it seems possible that costs may start to drop more steeply it’s not certain they will. There may be all manner of factors waiting to impose a floor that costs can’t sink below, or for that matter to constrain the overall size of the market in some way.

In short, there’s no cause for celebration just yet, and there’s a long haul ahead — but the news is not bad. For the time being, at least, optimism of the will may be possible without too much pessimism of the intellect.

Update: James Annan points to this interesting story — Japan going for a 30-fold increase in domestic solar power by 2030. Which is encouraging, but also illustrates the scope of the challenge; this ambitious programme would involve growth at only 17% per annum, and would provide in the end only 0.04TW of capacity

Further update: B J Stanbery at Heliovolt tells me that the plateauing of price in ‘87 does indeed correspond to the start of large scale subsidies by the Japanese government. Not the only factor, but a real one — it increased demand enough to lower downward trend in costs, and continuing/expanding subsidies there and in Europe have also had the effect of stabilising costs by producing a bottleneck in the silicon market (which may be alleviated, at least in part, by relocation of silicon foundries to places with both capital and cheap labour).

Graphs from Earth Policy Institute, picture of Silicon Valley used with very kind permission of Charles O’Rear

Cross-posted from Climate Feedback

There’s an interesting commenary in Nature this week by Steve Rayner of the James Martin Institute in Oxford and Gwyn Prins of the LSE, arguing that while emissions abatement is a global priority, the Kyoto Protocol is the wrong tool for the job — a one-size-fits-all approach that, among other failings, doesn’t actually look likely to deliver the reductions that it has promised. Unfortunately, as they argue, this sub-optimal approach has developed an iconic status of its own, so that in many minds to be against Kyoto is tantamount to being against any form of action on climate. They’re worried that this means people will uncritically attempt to follow up the Kyoto protocol (which expires in 2012) with a son-of-Kyoto that contains many or all of the same flaws, when they should be having a much more radical rethink.

In their words:

The Kyoto Protocol is a symbolically important expression of governments’ concern about climate change. But as an instrument for achieving emissions reductions, it has failed. It has produced no demonstrable reductions in emissions or even in anticipated emissions growth. And it pays no more than token attention to the needs of societies to adapt to existing climate change. The impending United Nations Climate Change Conference being held in Bali in December — to decide international policy after 2012 — needs to radically rethink climate policy…Already, in the post-Kyoto discussions, we are witnessing that well-documented human response to failure, especially where political or emotional capital is involved, which is to insist on more of what is not working: in this case more stringent targets and timetables, involving more countries. The next round of negotiations needs to open up new approaches, not to close them down as Kyoto did.

They go on to talk about some of the things they are in favour of: concentrating on the economies that are big emitters rather than treating all nations as equal partners in negotiation, a massive “wartime footing” increase in R&D, “bottom-up” emissions markets, increased spending on adaptation, and a multi-scale “madisonian” approach to the problem like that advocated by David Victor. which I guess encompasses a bunch of their previous points. Their conclusion:

Sometimes the best line of attack is not head-on. Indirect measures can deliver much more: these range from informational instruments, such as labelling of consumer products; market instruments, such as emissions trading; and market stimuli, such as procurement programmes for clean technologies; to a few command-and-control mechanisms, such as technology standards. The benefit of this approach is that it focuses on what governments, firms and households actually do to reduce their emissions, in contrast to the directive target setting that has characterized international discussions since the late 1980s.Because no one can know beforehand the exact consequences of any portfolio of policy measures, with a bottom-up approach, governments would focus on navigation, on maintaining course and momentum towards the goal of fundamental technological change, rather than on compliance with precise targets for emissions reductions. The flexibility of this inelegant approach would allow early mitigation efforts to serve as policy experiments from which lessons could be learned about what works, when and where. Thus cooperation, competition and control could all be brought to bear on the problem.

Illustration by Belle Mellor, borrowed from Nature

This week the International editions of Time are doing their annual “celebrating heroes” thing, praising people making a difference, and this year the chosen people are heroes of the environment. (Not available in the US print edition, I’m afraid — but hey, you get a J-Lo interview that we miss out on…) It’s a slightly odd list to my eye, satisfyingly broad-based (it has many people on it about whom most of us will know little or anything, but for whom there’s a good case to be made) but with some people on it that I wouldn’t choose and some omissions that I would have liked to see filled (and since they asked me for advice and I didn’t give as much as I should have, I really shouldn’t complain). It’s particularly weird, the week after the Nobel prize, not to see anyone associated with the IPCC singled out — or for that matter the IPCC itself. It’s also odd not to see much about farming and new farming approaches: we get the Prince of Wales (about whose troubling beliefs I wrote disobligingly for Time’s rivals Newsweek back in 1999, but the piece seems lost to the web Update: now found) and Jose Goldemberg, Brazilian biofuels pioneer, and that seems to be it.

My contribution is a short paean to Jim Lovelock. Excerpt:

Lovelock has been my subject, friend and inspiration for 20 years. Humble, stubborn, charming, visionary, proud and generous, his ideas about Gaia have started a change in the conception of biology that may serve as a vital complement to the revolution that brought us the structures of dna and proteins and the genetic code. That revolution came from the realization that biology required an understanding of living systems at a molecular level; Lovelock’s revolution, as yet unfinished, seeks to understand their mechanisms on a planetary level.

One thing that intrigued me is in the article written by Jim Hansen on Paul Crutzen. Hansen writes:

We would be wise to heed Crutzen on global warming, too, because he can fairly be described as the chief scientific caretaker of life on the planet … In contrast to the prompt attention paid to the ozone threat, foot-dragging on climate change has convinced Crutzen that major geo-engineering may be needed to cool the planet. He suggests a massive injection of sulfur into the stratosphere to form particles that reflect sunlight away. It’s a radical proposal that just might jolt some politicians into realizing what researchers learned long ago: that this scientists’ scientist always seems to be one step ahead of everybody else.

I don’t think Hansen (who’s also one of Time’s heroes, written up by Jeff Sachs) has been so sanguine about geoengineering before. Interesting times (Nature feature | blog post | and another.)

Picture of Jim Lovelock by Sandy Lovelock

Some things we have in Nature this week prompt me to a catch-up post on biofuels.

If you’re talking about photosynthesis as an energy source, then you’re talking about biofuels, and you have to respect both their promise and their pitfalls. They cannot be a wholesale replacement for fossil fuels. But they are already a large part of the energy economy in many poor countries, where the rural population relies on gathered firewood. Enhancing the efficiency of this biomass use (and replacing it with other renewable sources where possible) would be a worthwhile development goal simply in terms of reducing indoor air pollution. Beyond that, solid and liquid biofuels may have potential in various situations and niches. And by enriching soils, growing biofuels may also draw down some carbon from the atmosphere and tuck it away.

To make this work, though, we need to do two things. One is to find out how best to grow and use the most promising biofuel crops. Another is to stop wasting time and money and goodwill on corn-based ethanol and various low efficiency temeperate-climate-based biodiesel schemes.

We addressed both of these issues in Nature this week. My colleague Daemon Fairless reports from India on jatropha, a much touted oil crop.

Although there is reason to be enthusiastic about jatropha’s potential as a biodiesel feedstock in India and beyond, there is one rather sobering concern: despite the fact that jatropha grows abundantly in the wild, it has never really been domesticated. Its yield is not predictable; the conditions that best suit its growth are not well defined and the potential environmental impacts of large-scale cultivation are not understood at all. “Without understanding the basic agronomics, a premature push to cultivate jatropha could lead to very unproductive agriculture,” says Pushpito Ghosh, who has been working on the plant for the best part of a decade, and who is now director of the Central Salt and Marine Chemicals Research Institute (CSMCRI) in Bhavnagar.

I think it’s a fine and thought provoking read (and benefits from the fact that our recent redesign has encouraged sometimes robust discussion in the new comments threads).

We also have a leader on biofuels more generally, posted here in its entirety

Kill king corn

Biofuels need new technology, new agronomy and new politics if they are not to do more harm than good.

Zea mays has become the very emblem of plenty, with rich golden cobs of corn (maize) overspilling from some of the most effectively farmed arable lands on the planet. Jatropha curcas, on the other hand, is an unprepossessing and indeed toxic plant, better suited to scrubland and hedges. Yet in the world of biofuels, ugly-duckling jatropha has the potential to be, if not a hero, then at least one of the good guys, and a harbinger of better things to come. The golden-headed siren corn, on the other hand, is inspiring a wrong-headed gold-rush — to a dead-end of development that is polluting the modest aspirations the world might have for biofuels in general.

The common complaints about biofuels — and they seem to become more common by the day — are that they are expensive and ineffective at reducing fossil-fuel consumption, that they intensify farming needlessly, that they dress up discredited farm subsidies in new green clothes, and that they push up the price of food. All these things are true to some extent of corn-based ethanol, America’s biofuel of choice, and many are also true of Europe’s favoured biodiesel plans.

As far as the greenhouse goes, figures from the International Institute for Sustainable Development’s Global Subsidies Initiative put the cost of averting carbon dioxide emissions by using corn-based ethanol at more than $500 a tonne of carbon dioxide. What’s more, the heavy use of nitrogen fertilizer in growing corn leads to significant emissions of nitrous oxide, an even more potent greenhouse gas.

Despite this, the generous tax allowance of 51 cents a gallon given to ethanol blenders in the United States has made corn peculiarly profitable (provided that tariffs continue to keep out far more efficiently produced ethanol from the sugar plantations of Brazil). In a recent article in Foreign Affairs, C. Ford Runge and Benjamin Senauer of the University of Minnesota in Minneapolis point to estimates that this artificial price-hike will drive world corn prices up by 20% by 2010. This has a knock-on effect on other staple crops — more land for corn means less for wheat, for example. Higher prices are good news for farmers, including some of those in developed countries. But they can be bad news for the very poor, who spend a disproportionate amount of their income on food. According to World Bank studies, for the poorest people in the world a 1% increase in the price of staple food leads to a 0.5% drop in caloric consumption.

This sorry state of affairs has the small benefit of providing a stark, contrasting background against which to sketch out what a successful and sustainable biofuels industry might look like. It will be based not on digestible starch from staple crops such as corn or cassava, but for the most part on indigestible cellulose, with some room for biodiesels that, because they grow on marginal land, do not compete with food production. In the medium to long term, it will not seek to produce ethanol — a poor fuel — but a range of more complex fuels delivered by carefully designed microbes.

A rosy biofuels future will enjoy the benefits of free trade, allowing the countries and peoples of the tropics to ship some of their abundant sunlight north in the form of fuel. It will also require serious amounts of agronomic research — as we report on page 652, one of the most significant problems with jatropha is that, as yet, remarkably little is known about how best to grow and improve it. One focus of such research must be in the development of plants, such as jatropha, that make do on little water, and those that require low inputs of nitrogen. This is inherently more feasible in the case of fuels, where all that needs to be taken out of the system are carbon and hydrogen, than in the case of food, where there is a need to export nitrogen in the form of protein as well. Another focus will be on systems that actively store carbon in the soil, improving it for future agricultural use and at the same time doing a little bit more to take the edge off the carbon/climate crisis.

Biofuels are unlikely ever to be more than bit-players in the great task of weaning civilization from Earth’s coal-mine and oil-well teats. But they may yet have valuable niches — including some that allow them to serve some of the world’s poor, both as fuels for their own use and as exports. Provided, that is, that someone kills king corn.

A few links for those wanting more: Biofuels : Is the cure worse than the disease? (pdf), is a much talked about recent document from the OECD, and the ins and outs of its reception are discussed on the FT’s website. The point about greenhouse emissions from heavily fertilised biofuel crops was made recently by Paul Crutzen and others in this paper (pdf) discussed by Chemistry World and Futurepundit; the conversely optimistic point about biofuel plantations not needing to export nitrogen and thus opening up low intensity options has recently been raised by Robert Anex of Iowa State in work discussed here on the Biopact site. Biomass polycultures leading to increased soil carbon is the subject of a much discussed paper by David Tilman and colleagues in Science last year. This summer the FT ran an op-ed by Jacques Diouf of the UN Food and Agriculture Organisation on trade and development issues around biofuels. And then there’s John Mathews’ thought provoking Energy Policy article Biofuels: What a Biopact between North and South could achieve (subscription required), which is I think the first place I’ve seen the term “ergoculture” contrasted with agriculture.

Images from Valerio Pillar, www.jatropha.org and ~dabbler~, formerly jowo under creative commons license with thanks

There’s a letter to the editor in this week’s Nature from Jim Lovelock and Chris Rapley (late of the BAS, now at the Natural History Museum) suggesting that pumping up nutrient rich water from below the mixed surface surface layer of the oceans would increase the rate of photosynthesis in the seas above and thus pull down carbon from the atmosphere. Key para:

The oceans, which cover more than 70% of the Earth’s surface, are a promising place to seek a regulating influence. One approach would be to use free-floating or tethered vertical pipes to increase the mixing of nutrient-rich waters below the thermocline with the relatively barren waters at the ocean surface. (We acknowledge advice from Armand Neukermans on engineering aspects of the pipes.) Water pumped up pipes — say, 100 to 200 metres long, 10 metres in diameter and with a one-way flap valve at the lower end for pumping by wave movement — would fertilize algae in the surface waters and encourage them to bloom. This would pump down carbon dioxide and produce dimethyl sulphide, the precursor of nuclei that form sunlight-reflecting clouds.

There will be a lot of people who don’t like this suggestion for a lot of reasons (I wrote about some of the generalised disapproval of “geoengineering” in a Nature feature a few months back, and see also these blog posts (first | second) over at Climate Feedback). As well as the generalised mistrust of engineering interventions, though, I suspect that there will be some pretty specific criticisms, as my colleague Quirin Schiermeier notes in a news@nature article on the subject. Here’s his take on the downside:

“The concept is flawed,” says Scott Doney, a marine chemist at WHOI. He says it neglects the fact that deeper waters with high nutrients also generally contain a lot of dissolved inorganic carbon, including dissolved CO₂. Bringing these waters to the lower pressures of the surface would result in the CO₂ bubbling out into the air. So contrary to the desired effect, the scheme could result in a net ‘outgassing’ of CO₂, he warns. “There is no technological fix for this problem,” he says.

Others say such a project would have no net effect on CO₂ in the atmosphere. “At every meeting I’ve been to, when they have talked about this idea for surface ocean CO₂ removal, the point has been made that you would bring up nutrients and inorganic carbon in the same ratio as you remove as biomass,” says Ken Buesseler, a marine chemist at WHOI. And there are potentially many harmful impacts on sea life, he says.

I haven’t taken on board the wider press coverage, but I hear that various oceanographers — including some who are not ideologically averse to a touch of geoengineering — share these or similar doubts. One encouraging thing is to learn from Quirin that David Karl (author of a fine review that touches on some of the science behind all this in the Nature Reviews Microbiology oceans special I was enthusing about earlier) will soon be trying out a pump along these lines made by Atmocean and seeing what effects it has. That experiment will surely teach us something, just as the iron fertilization experiments being discussed at Woods Hole this week have. And just as in the iron case, there should be exciting science on how the oceans work here even if there’s no world-saving breakthrough.

Update: There’s a fairly full and convincing account of the issues in a comment made by Peter Williams of Bangor over at Climate Feedback 

They sound, I’ll admit, a little less appetising than corn-fed chicken. But they might be a source of fuel for some, and there was a short article about them in The Economist’s Tech Quarterly last week. The idea is to take effluent CO2 from power stations and bubble it through some sort of bioreactor in which there are photosynthetic algae. CO2 enrichment makes the algae grow faster. You then harvest the algae and turn them into something useful — such as biodiesel (the oil yield can be up to 30% for some algae). The Economist story highlights two companies working on this, GS Cleantech and GreenFuel Technologies. There’s more on algal biofuel in general in a recent Popular Science article.

I remember getting into a discussion about this on Synthesis, Rob Carlson’s blog a little while back. (As the biological technology archive on Synthesis shows, Rob knows a lot about this sort of stuff and keeps insightfully abreast of new developments, which is probably why he is quoted in the Economist piece). Looking back on it, I now think the discussion was somewhat at cross purposes. I was trying to think of the algae in terms of carbon capture and storage — as a way of cleaning the power station’s waste stream. Others were seeing it as a way of making biofuels better. Fossil-carbon based biofuels might be cheaper to produce than whole-plant biofuels, and as such could form part of the solution for some problems, such as energy security. They would also help a little with global warming, by displacing the use of fossil fuel oils.

But I don’t think The Economist is quite right in saying that “Using photosynthesis to capture exhaust gases from power plants could reduce the emissions produced by coal-fired stations.” The emissions stay the same — it’s just that an extra loop is put into the process, potentially making things more profitable. The original electricity generator takes out of the dug-up coal the energy that plants put into it in the past, oxidising the coal into carbon dioxide in the process. Then the algae reduce that CO2 to fuel by putting put some fresh sunlight back in. Then internal combustion engines in diesel vehicles reoxidise it. If the use of this biodiesel displaces the use of fossil diesel, there’s a net effect on global warming. But all of the carbon dioxide from the original electricity generator still gets into the atmosphere eventually. The advantages from the system are the same as those for any other biofuel — there’s no real decrease in the electricity associated emissions.

There might be a way of doing something similar, though, in a genuinely carbon neutral way. If the electricity generation is done with a small CHP plant fired by using biomass — say eucalyptus — it could simultaneously generate electricity, heat for domestic or industrial use and diesel for motor vehicles. The generating plant + algal bioreactors system becomes a way of making diesel out of a biomass that is efficiently grown but not good as a liquid fuel, while at the same time producing electricity. That might me quite a nice low/medium tech locally supported generation and transportation solution, if anyone wants such a thing. Of course you’d have to show that the diesel produced was more than enough to power the trucks bringing the wood to the generating plant to start making much of an impression, and there are other ways of turning wood into vehicle fuels, through pyrolysis and the like. But in a place with enough sunlight to grow serious amounts woody biomass and drive efficient algal growth in photobioreactors such a system might be in with a chance.

Image of algae in a photobioreactor by Dan Bihn, who probably reserves all rights

Via Gary at Muck and Mystery, various reports on the conference on biochar/agrichar/terra preta nova/what-you-will that just ended down in Australia. If you’re not up to speed on this, the general idea is that people could help solve a great many problems by putting enriching soils with reduced carbon in charcoal-like form. This gets rid of the carbon for a long time (charcoal is very refractory) and improves the soil in various not yet fully understood ways. My colleague Emma wrote a lovely feature on the subject last year. There’s what seems to be a thriving discussion board on the subject at Hypography.

The conference was opened by Tim “Weather Maker” Flannery, which is a pretty big name for a new field to manage to attract, I’d have thought. Here’s an overview of the conference by Kelpie Wilson of the Energy Bulletin. One interesting aspect is the idea of tying this issue to the issue of crappy stoves that drive indoor air pollution and waste a lot of energy.

Transect points, a blog by soil scientist Philip Small who, like Gary, is tracking this issue, has more reports in a round-up. As one of the people quoted says, the great thing about this field is that it opens up in so many different directions. Its also low tech enough to be of real use globally. The flip side of that is that different techniques will be needed in different places — this is unlikely to be a one-size-fits-all technology.

As it happens we’ve a look at the subject in Nature this week, too — a commentary (pdf) from one of the field’s main men, Johannes Lehmann of Cornell, which takes things forward nicely, I think. One of the advantages he points out for biochar sequestration — as opposed, say, to sequestration of carbon in aquifers — is that once the carbon is in the soil “it is difficult to imagine any incident or change in practise that would cause a sudden loss of stored carbon”. And he also argues that this sort of practise could be carried out at a serious scale:

I have calculated emissions reductions for three separate biochar approaches that can each sequester about 10% of the annual US fossil-fuel emissions (1.6 billion tonnes of carbon in 2005). First, pyrolysis of forest residues (assuming 3.5 tonnes biomass per hectare per year) from 200 million hectares of US forests that are used for timber production; second, pyrolysis of fast-growing vegetation (20 tonnes biomass per hectare per year) grown on 30 million hectares of idle US cropland for this purpose; third, pyrolysis of crop residues (5.5 tonnes biomass per hectare per year) for 120 million hectares of harvested US cropland. In each case, the biochar generated by pyrolysis is returned to the soil and not burned to offset fossil-fuel use. Even greater emissions reductions are possible if pyrolysis gases are captured for bioenergy production.

Similar calculations for carbon sequestration by photosynthesis suggest that converting all US cropland to Conservation Reserve Programs — in which farmers are paid to plant their land with native grasses — or to no-tillage would sequester 3.6% of US emissions per year during the first few decades after conversion; that is, just a third of what one of the above biochar approaches can theoretically achieve.

Those, Lehmann stresses, are rough calculations to highlight the potential, not realistic scenarios. But might it not make sense to start developing them into realistic scenarios? If you have inexpensive feedstock, this is a pretty intriguing technology.