Can coal come clean?

“The US has over 150 new coal power plants in the works. China opens one every five days.”

Old-style coal, of course, for all its many sins, is not yet ‘history’. Worldwide, consumption rises year on year - as it has for the past two centuries. No less than 38% of all electricity is generated by burning it - more than gas and nuclear combined. The US alone has over 150 new coal power plants planned or being built - and China opens a new one every five days. Even in the UK, despite the near closure of the mining industry and the accompanying ‘dash for gas’ in the power sector, coal-fired generation still meets one third of our electricity demand.

But, with the world staring the prospect of climate chaos in the face - and China choking and smarting from the all-too-familiar reality of sulphur and nitrogen oxide pollution - those figures surely spell ‘problem’ rather than ‘solution’. And almost no one denies the problem. Coal, even the best quality coal, is both dirty in the conventional sense, and a shockingly high-carbon way to generate electricity, with CO2 emissions per unit of power that are close to double those from gas-fired plants.

 “Clean coal depends critically on carbon capture and storage.”

Which is where the promise - or, as others would have it, the oxymoron - of clean coal comes in.

The ‘clean coal’ promise has several parts to it, starting with processes to take out the toxic stuff. There are various ways of doing this - some of them were developed 10 or 15 years ago, so they’re relatively well tried and tested. New techniques can also raise the efficiency of coal-fired power plants, bringing their energy conversion rates up from 35% or so to around 50% (more bang for your yuck, as it were). Put these two stages together - they tend to be quite a good technological fit - and some people would call that ‘clean coal’ already. But for coal to be a low-carbon contender, there are two more crucial steps, known in the jargon as carbon capture and storage (CCS). This involves removing and capturing that troublesome CO2 inside the plant, either at the pre-combustion stage or in the exhaust flue, before it is emitted to the atmosphere - and then storing it somewhere out of harm’s way, probably underground…

You can’t read an energy policy document these days without bumping into CCS. The EU’s latest energy future scenarios talk of “non-carbon sources” as including “renewable, nuclear, and carbon capture and storage”. Since the UN’s Intergovernmental Panel on Climate Change published a special report on the subject in November 2005, carbon storage has gained acceptance as a legitimate method of CO2 mitigation. This opens the prospect of funding such projects through the Clean Development Mechanism, potentially giving rise to carbon credits that could be tradable within the EU’s emissions trading scheme. The Stern review speaks favourably of CCS. Another obstacle is being removed by the emerging international agreement that storing carbon in saline aquifers beneath the sea bed - one of the front-running geological options - would not fall foul of the treaties that outlaw waste dumping at sea.

So far, so positive, you might think. But if clean coal depends critically on carbon storage (which it does), then that end of the equation needs to be not just legitimated, but tried and tested (which it isn’t - and won’t be, in commercial terms, for another decade). The potential uses of carbon storage go far wider than the coal industry; indeed, leading experimental applications like that at Sleipner [see GF46, ‘Exchange of Fire: Should CO2 go underground?’], run by the Norwegian firm Statoil, are linked directly with oil and gas interests. But if carbon storage, underground or in some other form, proves impractical, unreliable or prohibitively expensive, then the ‘clean coal’ route is a blind alley too.

Not that this has discouraged ambitious energy companies from coming forward with plans for ‘carbon-capture-ready’ power stations. In Australia, the world’s leading coal exporter, the federal and coal state governments came together last October to set up a AUS$1.1 billion development fund. The industry will contribute nearly 30% of this, and Ken Talbot, chief executive of mining company Macarthur Coal, is adamant that it’s time to stop talking about clean coal and start spending serious money on it. “At the end of the day,” he says, “our aim is to go to zero emissions. If we can do that, then coal will become a fuel of choice.”

Here in the UK, three companies have announced new ‘clean coal’ power station plans in the last 12 months [see panel opposite]. An EU ‘backed project envisages establishing a plant in China too, by 2015. “If the technology can be made to work,” said Alan Johnson a year ago when he was trade and industry secretary, “clean coal could play a crucial role in delivering increased energy security and helping the environment - and not just in the UK, but crucially in fast-growing economies like China and India where we are beginning to share this new technology for mutual benefit.”

 “What if the optimistic timescale estimates unravel? Should we go on keeping the clean coal option open while the carbon keeps pouring out?”

So far, the UK government has only put £35 million of its money behind clean coal technology. US government backing has been much more loudly trumpeted, but the FutureGen project so proudly announced by President Bush four years ago has yet to choose its site…

In any event, government money can’t make clean coal a winner, unless the market sees it as an attractive option. So far, there’s been no rush to invest. Only a handful of the US’s 150 planned or proposed new coal power stations incorporate what’s generally seen as the most promising technology for carbon capture, based around the ‘integrated gasification combined cycle’ (IGCC) process, which aims to capture the carbon dioxide while turning the coal into gas prior to combustion. And any power station whose carbon capture depended on post-combustion flue gas scrubbing technology would consume an estimated 10% to 40% extra energy to do that job. Either route might theoretically reduce emissions by up to 90%, but there’d still be the problem, and cost, of providing the infrastructure to take the CO2 off to… wherever.

“The cost that worries environmentalists the most is the opportunity cost.”

In short, a great deal is effectively still being kicked into the middle distance in terms of the actual workability of the CCS element in ‘clean coal’. This leaves most environmentalists highly suspicious. The cost they worry about most is the opportunity cost - the potential diversion of attention, funding and research from the pursuit of energy efficiency and the development of genuinely clean renewable energy technologies. Another real concern is that ‘clean coal’ (like nuclear) offers no alternative to the model of centralised energy generation, feeding into a grid - and ignoring all the advantages of distributed small-scale generation at, or close to, the point of use.

Greenpeace International takes an unequivocal position. “There is no such thing as clean coal,” it says. “Obvious oxymorons aside, it is mad folly to replace one environmental disaster with another. Climate change will be stopped by increased energy efficiency, and a shift to renewable energy such as wind, solar and biomass. It will not be solved by taking a step backward to the dirty and dangerous technologies of the last century.”

Do we need it?

So should we indeed turn our collective back on coal, as the most flawed fuel even among the fossil varieties, and focus on finding a more viable way forward?

Part of the problem with renouncing coal is the ‘I will if you will’ conundrum, and the widespread and hard-to-dispute perception that China won’t. With the ever-expanding energy needs of its extraordinary economic growth and rising living standards, China recently overtook the US as the world’s largest coal consumer, and generates the overwhelming majority of its electricity that way. Seen in this perspective, the only hope for bringing China’s coal-firing carbon emissions within any kind of limit is to pursue clean coal technology and fund its deployment there.

Then there’s the simple economics. Coal firing in its commonest current form is usually a low-cost option - when it doesn’t have to factor in its environmental impact. Unclean coal won’t go away unless it is regulated out of existence, or we get much higher carbon prices emerging from cap-and trade arrangements like the EU emissions trading scheme. However, the ‘cheap coal’ card is a bit trickier to play with ‘clean coal’: the more you clean it up, the more the costs go up (which helps explain why there’s more talk than action on this front). Economist Marc Jaccard, a powerful advocate of a (nuclear-free) energy mix that combines renewables with responsible use of fossil fuels, says CCS should be viable if oil is over $35 per barrel, but the actual costs of carbon storage are really still in the realms of guesswork - and, as energy prices rise, more renewable energy technologies come into the frame anyway.

“The clean coal model ignores all the advantages of distributed small-scale generation.”

Another factor is the sheer familiarity of coal. Admittedly, its image could scarcely be called benign, blighted as it is by grim working conditions in the mining industry, appalling occupational health problems, a shocking accident record, and brutal impacts on the landscape, the more so in this age of strip mining and “mountaintop removal”. Yet there’s something comfortingly low-tech about coal. It’s just not, well, volatile. You move it around in trucks, trains, boats, barges even. And you store it in… er, heaps, actually. These just don’t seem like scary targets for terrorist attacks, whereas the public imagination can quickly conjure up any number of nightmare scenarios involving oil terminals, gas pipelines and nuclear power plants.

Coal’s biggest plus points on energy security, however, are its plentiful reserves and their distribution across the globe. The only fossil fuel that can be confident of sustaining output well into the next century, coal has known reserves of 909 billion tonnes oil equivalent (according to BP’s Statistical Review of World Energy 2006), enough to last 155 years at current rates. And the geopoliticians set great store by the fact that they aren’t all concentrated, like oil and gas, in the Middle East or Russia. The biggest reserves by far are in the energy-hungry US [see chart], and China too is among the well-endowed.

“Coal heaps just don’t seem like scary targets for terrorist attacks.”

Such arguments carry enormous weight. But there’s a danger that they’ll merely persuade us to keep the coal option open, in anticipation of clean coal technology - while the optimistic timescale estimates unravel, the carbon keeps pouring out, and the quest for viable answers swallows up time and funds.

The mediaeval alchemists had a quest. They sought a substance (or process) to transform corruptible base metals into incorruptible gold. Few doubted that, if found, this ‘philosopher’s stone’ would repay the effort they invested. But they never found it. With hindsight, we tend to regard it as a blind alley, a waste of their skills, their knowledge, their time. We don’t have that time.

9 March 2007

Roger East