INSIGHT: Carbon sequestration; possible or pipedream?

23 July 2009 13:08  [Source: ICIS news]

By Joe Kamalick

WASHINGTON (ICIS news)--Carbon capture and sequestration (CCS) is central to US and other nations’ hopes of continuing to use abundant coal resources for power generation without pouring billions of tonnes of carbon into the atmosphere.

Indeed, climate change legislation advancing in the US Congress more or less assumes that carbon capture and sequestration technologies will be available for broad commercial application in the very near future.

The viability of CCS is crucial to US energy plans because the country depends on coal-fired generation for half of its electric power. If climate change legislation should accelerate a wholesale shift away from coal for environmental reasons - a shift that is already under way - the nation could be facing a catastrophic energy shortfall.

The trouble is that carbon capture and sequestration - as yet unproven at commercial scale - just might be a pipedream.

A leading authority on oil and gas drilling holds that wide scale carbon capture and sequestration will never be practical or cost-effective, that it could contaminate ground water, will cost trillions of dollars, raise energy prices - and won’t have meaningful impact on global concentrations of greenhouse gases (GHG).

Michael Economides, a professor of chemical and biomolecular engineering at the University of Houston, makes that case in a paper prepared earlier this year for the Society of Petroleum Engineers (SPE), in which he is a distinguished member.

Economides uses the 1997 Kyoto Protocol as a starting basis. That agreement provided that developed nations were to reduce their carbon dioxide (CO2) emissions to 5% below 1990 levels by 2012.

The US was a signatory to the Kyoto treaty but the Senate, which must approve treaties, overwhelmingly rejected the deal with a 95-0 vote.

In his paper, Economides contends that had the US tried to comply with the treaty, which went into force elsewhere in 2005, the US would have had to drill more than 66,000 CO2 injection wells in 2008 alone, rising to 160,000 by 2030.

For comparison, he notes, about 40,000 oil and gas wells are drilled annually in the US.

In addition, the costs would be enormous, he contends.

Citing US Department of Energy (DOE) data, he notes that CO2 capture from flue gas alone costs about $150/tonne. 

“Capturing 90% of CO2 from Integrated Gasification Combined Cycle power plants takes 20-25% of the plants’ energy,” Economides says. “It would increase the capital costs by 47% and the total cost of electricity by 38%,” he said, citing an Environmental Protection Agency (EPA) study.

The cost of compressing CO2 is about $17/tonne, and building and providing power for pipelines to move the liquefied gas to sequestration sites would run around $3m/mile.

In addition, Economides says, “it is reasonable to assume an average of $10m to drill and complete a CO2 injection well”. 

Those costs along with operational, maintenance and labour expenses mean that “over $1,000bn [€700bn] annually may be needed for the operation if all the cost is considered,” he said.

Then there is leakage, he warns. “Under supercritical conditions [high underground pressures], CO2 is less dense than water and tends to migrate to the top of the storage formation,” he says. “It is inevitable that the highly pressured CO2 will leak at some extent due to the permeable nature of the porous rocks, causing uncertainties on the storability of the reservoirs.”

Under those pressures, Economides argues, “CO2 is a highly effective solvent and capable of extracting contaminants from geological materials such as polycyclic aromatic hydrocarbons”. Citing other research, he contends that “those toxic compounds could be mobilized and could compromise water quality in nearby aquifers”.

Worst of all, Economides argues that even if all Kyoto signatory nations had lived up to their commitments - of the 36 obligated developed nations almost all have instead increased their CO2 emissions - the impact on global temperatures would be negligible.

However, a top Department of Energy official in charge of sequestration research and development contends that CCS is not only viable and cost-effective, it will be ready for widespread commercial application by 2020, just over a decade away.

John Litynski, division director for carbon sequestration at DOE’s National Energy Technology Lab in Pittsburgh, Pennsylvania, said that the number of injection wells that might be needed for a national sequestration effort is within reason.

Although Litynski did not want to address Economides's arguments specifically - not having seen the paper - he contends that the US already has “hundreds of thousands” of injection wells for oil and gas field remediation, industrial and municipal waste, mining and hazardous materials disposal.  The nation could ramp up to the needed injection rate when commercial sequestration is ready, he said.

Litynski also noted that current injection operations are carefully monitored and regulated by EPA’s Underground Injection Control Programme.

“That programme ensures that those fluids remain under the surface forever,” Litynski said. “The permitting process ensures that those fluids remain underground and that there is no migration.”

“CO2 would be handled in the same way, and that is a [regulatory] structure that has been in place for more than 30 years,” he argued.

Litynski said it is too early to estimate what costs would be for a nation-wide commercial sequestration effort.

“If we had to install sequestration today, maybe it would be cost prohibitive, but it is a proven technology and we can drive down the cost and have minimal impact on the cost of electricity."

As to sequestration’s impact or lack thereof on atmospheric temperatures, Litynski said that CCS must be one of several tools needed to combat global warming.

“There is no one silver bullet or one type of answer,” he said. “And CCS will be a principal technology if we are to achieve emissions reductions goals.”

He cited studies by the International Energy Agency (IEA) and the UN’s Intergovernmental Panel on Climate Change (IPCC) finding that carbon sequestration could account for up to 50% of the greenhouse gas reductions needed to arrest global warming.

“Without CCS it is clear that we will not be able to meet those reduction targets,” Litynski said.

“We have a robust research programme, and the goal is commercial adoption by 2020,” he said. “Our technologies will be ready at that time for deployment.”

So, who’s right?  Economides or Litynski?  Congress is rolling the climate control dice on the assumption that DOE research will deliver.

($1 = €0.70)

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By: Joe Kamalick
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