Carbon Capture: no real solution

I was interested to note that carbon dioxide gas concentration rises are not evenly spread in the atmosphere around the world at any particular point in time, due to the location of power plants, factories and cars (mostly for the moment in the global north), the time taken to mix the extra injected CO2  gas globally (about a year), and the differing annual forest absorption/decay cycles and sea absorption/release processes around the world.

http://carboncycle2.lbl.gov/resources/experts-corner/annual-cycles-of-atmospheric-co2-concentration.html

You can watch it happening, and the result getting worse year by year, in this excellent animation: www.youtube.com/watch?v=vA7tfz3k_9A  

So what can be done about it?  Carbon Capture and Storage (CCS) is offered as a way to allow us to continue to burn fossil fuels, and, given the strength of the fossil fuel lobby, it certainly has powerful backers, who argue the case for rapid expansion, for example in the UK: www.ccsassociation.org/press-centre/reports-and-publications/

However, despite pilot projects and programmes around the world, progress has been slow, and so far it is undeveloped on any significant scale, with its cost likely to be high.  www.technologyreview.com/news/428355/will-carbon-capture-be-ready-on-time/

There are also uncertainties at to its long term viability-  e.g. would the stored CO2 stay in place  in open aquifers indefinately?  In any case it would only be a partial solution to emissions-   it would not capture any where near 100% of what a power plant produces. And it would certainly not reduce CO2 levels in the atmosphere. 

One idea for that is to reabsorb CO2 from the air. For example, Air capture of atmospheric CO2, coupled with chemical storage, has been proposed as a somewhat desperate geo-engineering attempt to deal with climate change.  The idea is to absorb CO2 by sucking air through vast towers of sodium hydroxide, with the resultant bicarbonate mulch then being stored, or recycled, to release the CO2 for storage in some other form. Superficially it sounds attractive - you can capture CO2 anywhere, not just directly from power plant exhausts. Fill deserts with so-called ‘green trees’. But quite apart the need to store or process the huge volumes of residues, and keep fresh supplies of NaOH coming, the proportion of CO2 in the air is around 0.039%, so to capture a ton of CO2 you would have to process over 2500 tons of air. The overall energy cost would be high. And, more subtly, it has been argued that absorbing CO2 from the air might lead to disruption of natural CO2 absorption processes, by plants and the sea, so you may be no better off. 

That argument seems odd at first glance. Surely getting CO2 levels back down a bit is good, however you do it. Unfortunately that ignores the fact that the seas have absorbed about 50% of our CO2 emissions, and, if we manage to reduce CO2 levels in the atmosphere by air capture, then it may be that some of this huge sea reservoir would be slowly outgassed to replace at least some it. Certainly one study, reported in Environmental Research Letters, suggested that mass removal of air CO2 ‘leads to an 
increase in the ocean-to-air CO2 flux, largely replacing the air CO2 
removed’  i.e. in time, the seas would outgas trapped CO2 pushing atmospheric levels back up. http://iopscience.iop.org/1748-9326/5/2/024011

This process would take time and the rate of outgassing might be low, so initially air capture would still yield a net reduction in atmospheric CO2. There’s evidently a complex balance between absorption and release processes, depending on, amongst other things (including temperature), the small partial pressure difference.  Also, over time, some of the absorbed CO2 is sequestered as geological carbon in seabed/rock formations and some say we could inject more to get it stored this way. http://web.mit.edu/energylab/www/pubs/overview.PDF

For the moment though, most of what’s there is still in surface layers, interacting with the atmosphere. There is a lot of it. Even so, it is possible that, if air extraction was to go ahead on a very large scale, eventually most of the extra sea-absorbed CO2 would presumably be outgassed, so that then, if air capture was continued, the atmospheric CO2 levels could be reduced much more. But it would take a very long time.

The aforementioned ERL paper notes that there is another approach which might be more effective- direct ocean CO2 extraction i.e. from the sea itself.   It argued that ‘excess ocean CO2 removal is required for any effective air CO2
 capture scheme because removal of air CO2 alone will simply reduce air 
CO2 concentration relative to that in the ocean.’ Indeed it boldly claims that, with sea capture, you then won’t need air capture: ‘schemes that consume/remove and sequester excess ocean 
CO2’ can ‘effectively address both excess
 ocean and air CO2, sidestepping the need for direct air CO2 capture.’

Removing CO2 from sea water has its problems (e.g. it needs energy), and it would still take a very long time and a huge effort to make much difference, but the concentration is about 140 times higher than in air, and some clever ideas for sea extraction have emerged: www.pnas.org/content/early/2013/05/30/1222358110.abstract Though if synfuels are produce using the CO2, as some suggest (to give an economic incentive), when they are burnt the overall process is no longer CO2 negative. For an interesting overview (even it does suggest using nuclear energy to run the system)  see: http://bravenewclimate.com/2013/01/16/zero-emission-synfuel-from-seawater/  

There are other options, with perhaps less eco-worries, e.g. biochar production using biomass- trapping CO2 more permanently as charcoal and using this to help to enhance soil fertility and carbon retention : http://carbon-negative.us/docs/CharcoalVision.pdf  and www.biochar.ac.uk/ But see: http://climate-connections.org/2013/07/24/the-problem-with-biochar/  and this absorption option  doesn’t avoid the sea outgassing problem.

What about BECCS, biomass energy carbon capture and storage?  Depending on the source, BECCs should be CO2 negative, and although that doesn’t escape the sea outgassing problem, the energy output would replace fossil burning and new CO2 additions to the atmosphere. So some say that, since geological/aquifer CO2 storage space will be limited, BECCS projects should be given priority over fossil CCS. Though there are still worries about whether CO2 captured from whatever source can be safely stored underground for ever, and about the ecological and land use impacts of the large scale use of biomass.

Tragically, it seems then that most of these artificial /bio carbon capture options have problems, and, even if expanded massively, BECCS maybe aside, would not be able to make a large difference except over a very long period   Worse still, the albeit slow dissolved CO2 blow back may also mean that, sadly, the CO2 absorption from reafforestation, a much more attractive proposition on many levels, would also be undercut and may not be too much (climate) use long term, unless done on a very large scale. Certainly the overall scale of CO2 re- absorption needed, by whatever means, to make much difference is vast. As the ERL paper noted, ‘to maintain atmospheric CO2 concentrations at pre-industrial levels for centuries, ultimately an amount of CO2 approaching the total cumulative amount of anthropogenic CO2 emissions would need to be removed from the atmosphere’. And, it seems, the sea. And it should also be said, the land- excess CO2 has also ended up being trapped in land sinks. Basically it’s too big a job: http://iopscience.iop.org/1748-9326/5/2/024011/pdf/1748-9326_5_2_024011.pdf

Moreover some of these carbon capture options have environmental side effects. Certainly, when it comes to some of the larger scale geo-engineering projects, then we enter a realm where there could be major impacts: seeding the sea with ferric compounds to increase bio-productivity, blocking sunlight with aerosol particles, orbital reflecting mirrors and so on. A recent study concluded that, not only could there be local or global side effects, some of them possibly irreversible, the overall effectiveness was low: even if continuously deployed on a massive scale, the climate engineering methods it evaluated could ‘only sequester an amount of atmospheric CO2 that is small compared with cumulative anthropogenic emissions’ and were ‘unable to prevent the mean surface temperature from increasing to well above 2C by the year 2100’. www.nature.com/ncomms/2014/140225/ncomms4304/full/ncomms4304.html

So we can’t repair the earth much, except maybe very long term, with some risks, and the higher the temperature the harder that will be. Too much CO2 has be released, and trapped partly in the seas and land, to let us get the planet back even near to how it once was. But we can stop making it worse by not burning fossil fuels. That seems the only major option. Unless Gaia comes to the rescue and allows the sea to absorb a lot more CO2 without getting too acidic!  Or some other natural feedback loop intervenes.

Thanks to Jo Abbess from Claverton Energy Group for some of the links.

Shale gas- costs and limits

 There has been speculation and assertions about the impact of shale gas on gas prices. UK PM David Cameron said unequivocally that ‘fracking has real potential to drive energy bills down… gas and electric bills can go down when our home-grown energy supply goes up’. But Lord Stern disagreed, arguing that the economics were very uncertain.

 www.independent.co.uk/news/uk/politics/baseless-economics-lord-stern-on-david-camerons-claims-that-a-uk-fracking-boom-can-bring-down-price-of-gas-8796758.html         

While Sir David King, ex Chief Scientist, said the eco-impacts of shale gas may be large and the UK contribution limited: www.theguardian.com/environment/2013/sep/16/david-king-fracking-shale-gas

Energy Secretary Ed Davey warned that it was ‘no quick fix and no silver bullet’ and was at ‘the very early stages’. So the UK was unlikely to see benefits from shale gas until the next decade and, with the uncertain scale and nature of the resource, it was ‘far from clear that UK shale gas production could ever replicate the price effects seen in the US’. www.ft.com/cms/s/0/6090d082-1954-11e3-83b9-00144feab7de.html#axzz2eQ6sk4mW

However some see the prospects differently given international energy trading patterns: www.independent.co.uk/voices/letters/letters-frack-and-cut-gas-prices-by-a-third-8800063.html . It is certainly complicated. Prices have certainly fallen in the USA, though that may be a unique event- the geology and population densities in the EU are different. So is the market. The US doesn’t import much gas, and in the past hasn't used as much gas for heating as the UK- it’s been expensive there and they didn't have the North Sea boom. So Shale gas has had a big impact, expanding the market and pushing the price down. They can even export some-and some freed up coal. In the EU there is a big internal gas market fed from the North Sea but increasingly from Russia, and prices are competitive- topped up though by expensive imports of LPG. Shale gas might reduce the scale of the later, but then LPG may get cheaper now the USA is exporting into the world market. So shale gas may change patterns of supply, but it’s hard to say whether a shale gas boom in the UK or EU would reduce prices. Especially since Japans use of LPG to replace nuclear (hopefully temporarily until renewables can take over) has raised global LPG prices.

Then again the shale gas boom may not last. Well productivity falls rapidly, so early gains may not be sustained: you have to invest continually in new wells and the costs are significant.  Jeremy Leggett has provided regular updates to his book ‘The Energy of Nations’ and says ‘the top 15 players in US shale drilling have written off $35 billion since the boom started, and that investors are beginning to pull out. Meanwhile, production has peaked and is now falling in all but one of the major shale-gas drilling regions. The boom is looking like it could turn into a bust before too long’. www.jeremyleggett.net/

So not surprisingly views on what will happen next vary.  Writing in New Scientist (10/8/13), Michael Brooks noted the concern expressed by Sergey Paltsev, an energy economist at MIT, that, seduced by a false promise of cheap, plentiful energy from shale gas, we will cut back on investment in renewable alternatives. If so, Brooks said, as the costs and emissions associated with shale gas rise, as they inevitably will, we will end up on a costly bridge to nowhere. DECC by contrast still sees shale gas as the bridge to a green energy future.

However, despite DECC’s assertions that shale gas has lower GHG impacts than coal or imported LPG, the environmental impact issues continue to be debated.  http://www.eeb.cornell.edu/howarth/web/Marcellus.html Fugitive emissions/leaks of the powerful GHG methane are a key worry, water contamination another, along with the sheer volume of water needed, and there is also the possible risk of radioactive radon gas pollution: http://gdacc.org/2012/01/10/radon-in-natural-gas-from-marcellus-shale-by-marvin-resnikoff-radioactive-waste-management-associates/


For a good overview of the impacts issues see www.carbonbrief.org/blog/2013/08/shale-gas-more-or-less-polluting-than-coal/ For a short if partisan guide: http://www.resilience.org/stories/2014-04-21/those-fracking-lies And for an independent technological assessment, which identifies a range of worrying drilling and site problems associated with fracking, see: www.davidsmythe.org/fracking/fracking.htm

The debate in the UK has gone on, as more details emerged. An AMEC report for the government, said that a major fracking effort could deliver about 25% of the UK's annual gas needs in its peak years in the 2020s and provide up to 32,000 jobs. But that could involve up to 2,880 wells being drilled and run for 20 years.  Fracking would need 58-144bn litres of water, with up to 108bn litres of waste water being contaminated by fracking chemicals and radioactive elements that occur naturally in rock. This would AMEC said ‘place a significant burden on existing wastewater treatment capacity’.  Some of the fracking water would need to be trucked into sites, with wastewater being trucked out, and Amec estimated 14 –51 journeys a day for each site, which ‘could have an adverse impact on traffic congestion, noise or air quality’. www.gov.uk/government/consultations/environmental-report-for-further-onshore-oil-and-gas-licensing

However the pressure is on to press ahead fast. Energy Minister, Michael Fallon said. ‘There is a huge amount of shale gas underneath us all and what is important for public confidence is to show the regulatory framework is robust’ and Shale gas fracking could take place across over half of Britain if plans to ‘step up the search’ for shale gas and oil are fruitful, with many new exploration sites being licensed.

To help things along Local Councils that back shale gas projects will get to keep 100% of the business rates collected from the schemes, rather than the usual 50%, and up to £10m per wellhead if shale gas is successfully extracted in their communities, through a1% levy on revenues. Fallon said ‘We expect 20 to 40 wells to be drilled in exploration over the next couple of years and I think it's very important that local communities see some of the benefit”.

So what next? While the Lords Economic Affairs select committee said that the UK was  ‘exceptionally fortunate’ to have substantial shale gas and oil resources, and urged the Prime Minister to lead a ‘sustained and concerted effort’ to go ‘all out’ for shale development , it accepted that drilling could not proceed without the support of the public, even if the majority of environmental and health concerns were ‘unfounded’ and leading to unnecessary delay. DECC, and Ed Davey especially, has been less that forthright is backing rapid expansion: DECC says shale gas has to be put in perspective: it should be pursued in combination with carbon capture and storage, and should not be seen as an alternative to renewables.

www.gov.uk/government/news/davey-uk-shale-gas-development-will-not-be-at-expense-of-climate-change-targets

That view was reinforced by a WWF reaction relayed by the Economist Intelligence Unit: the UK needed to decarbonise, so shale gas, which may not be cheap, plentiful or fast, was a diversion  http://www.economistinsights.com/energy/opinion/uk-shale-gas?

And  Paul Mobbs writing  in The Ecologist saw it unequivocally as a diabolical stitch up:

http://www.theecologist.org/News/news_analysis/2417288/fracking_as_bad_for_climate_as_coal_uks_dodgy_dossier_exposed.html

The National Trust and CPRE may be wobbling a bit, but local protests continue, further stimulated by the spectre of gas pipe link up projects going ahead without consultation. 

So what’s the bottom line? We can all agree that tight regulation will be needed if shale gas  goes ahead on any scale, but it is still far from certain that it will- much less should. Not least since the threat to renewables still remains. AD biogas from waste would be a better bet surely. Some say it will in fact all blow over: the US shale gas boom is a short term one-off episode driven more by speculation than by the scale of the realistic resource. Some see it accelerating in net terms, up to 2040 and beyond (see the EIA’s projection for the US at http://www.eia.gov/pressroom/presentations/sieminski_03012013.pdf). Others think it will fade way long before then.  In practice the outcome is likely to be shaped by other factors- for example, if carbon emissions are taken seriously then shale gas use may be constrained, unless CCS can be deployed on a wide scale.  The US EIA suggested that under high carbon costs, renewables and nuclear would boom more, with coal being all but extinguished. In the short term however shale gas does represent a threat to non-fossil fuels. It’s one reason why nuclear has declined so dramatically in the USA, but its impact on renewables has so far been more muted- as their costs fall, they are still booming in the US and elsewhere, although perhaps not as much as they would if there was no shale boom. Then again there are those that say fossil gas, of whatever sort, is a good partner for renewables. So shale gas represents no real problem. Although try telling that to those having fracking projects imposed on them!