Costs play dampener on CCS

After the brake on the US FutureGen project and closure of a CCS unit in West Virginia, now it is the turn of UK to face some truths in the area.

A major carbon capture and sequestration (CCS) project planned in Scotland may soon bite the dust. The project, slated for the Longannet coal power station, to the northeast of Edinburgh, has been heavily supported by the government, but apparently the price tag might be too high in current economic and political conditions.

The Longannet station owned by ScottishPower, has a massive generating capacity of more than 2300 megawatts. The idea was to capture some of the CO2 emissions and bury them under the North Sea. But the report in The Guardian noted: "The investment case for CCS remains uncertain due to the absence of a firm timetable and a clear roadmap for how these demonstrations will enable and form part of a large scale deployment of CCS in the UK."

The report also notes that most likely 20 to 30 gigawatts of CCS-fitted power plants must be in operation by 2030 in order to meet emissions targets and a growing energy demand.

Perhaps CCS is an idea before its time, at least for now!

Possible, but expensive

A new study by the American Physical Society shows that it's technologically feasible to take CO2 out of the atmosphere but to do so will cost at least $600/ton, 7.5 times more expensive than capturing emissions from power plant smokestacks.

Meanwhile, a team of leading researchers from some of Australia's top universities and research institutes will join forces to develop new ways to capture and transform carbon dioxide. The team will explore how smart materials, called metal-organic frameworks (or MOFs) can be used to capture and concentrate CO2 with minimum energy requirements.

These materials are capable of absorbing large amounts of CO2 into nanometre-sized holes within their structures, leading potentially to the efficient separation of this gas from power station flue gases.

The team will also look at how MOFs can be used to convert CO2 into useful substances, including feedstocks for agriculture, hydrocarbon fuels and precursors to complex metal oxides for use in solar cells.

Never say die! What perhaps we are forgetting is that fossil fuels will not last forever. Already peak coal is on the near horizon. Does it make sense to invest so much money on something short-lived?

More research on CCS needed

Leaks from carbon dioxide injected deep underground to help fight climate change could bubble up into drinking water aquifers near the surface, driving up levels of contaminants in the water tenfold or more in some places, according to a study by Duke University scientists.

Storing carbon dioxide deep below Earth's surface, a process known as geosequestration, is part of a suite of new carbon capture and storage (CCS) technologies being developed by governments and industries worldwide to reduce the amount of greenhouse gas emissions entering Earth's atmosphere. The still-evolving technologies are designed to capture and compress CO2, emissions at their source -- typically power plants and other industrial facilities -- and transport the CO2 to locations where it can be injected far below the Earth's surface for long-term storage.

But the technology involves many hurdles besides the aspect of a chemical unit next to a power plant! Will the areas chosen hold the gas or leak it eventually? How do we handle the loss of efficiency of plants when CCS is implemented? And like this study says, water contamination is another concern.

This shows that CCS will have to be studied more in detail before it becomes a way out. The study identified four markers that scientists can use to test for early warnings of potential carbon dioxide leaks. Along with changes in carbonate concentration and acidity of the water, concentrations of manganese, iron and calcium could all be used as geochemical markers of a leak, as their concentration increase within two weeks of exposure to CO2.

For now, we have to live with CO2 in the atmosphere!! Better be sure before we open yet another Pandoras box.

If the carbon leaks...

CO2 sequestration has many potential advantages over other forms of climate geoengineering. It makes good sense to modify the Earth's radiation balance by putting carbon back in where it came from. Atmospheric CO2 is long-lived and evenly-distributed globally making it possible to manage it in a long-term, controlled way with less chance for unpleasant climate surprises. But is it really safe, especially in the recent oil spill background? If we cannot cap oil, can we do the same for a gas? Is it a good enough excuse to continue using fossil fuels?

Gary Shaffer, professor at the Niels Bohr Institute, and leader of the Danish Center for Earth System Science, made long model projections for a number of sequestration/leakage scenarios. His results show that leakage of the stored CO2 may bring about large atmosphere warming, large sea level rise and oxygen depletion, acidification and elevated CO2 concentrations in the ocean.

Admitting the advantages of CCS, he notes "However, one should not underestimate potential short and long-term problems with leakage from underground reservoirs. Carbon in light form will seek its way out of the ground or seabed. The present situation in the Gulf of Mexico is a poignant reminder of that."

Bury it, forget it?

Till such time when nanotechnology and microbes that take in carbon dioxide and spew fuel (methane) step out of the realm of possibilities, most of the world will continue to rely on coal for their primary energy needs.

But, coal, everyone knows is not a honourable gas. That being so, how does one take the bite out of coal? CCS or carbon capture and sequestration. Here, the carbon emitted by thermal plants is captured and buried underground. Out of sight, out of mind.

But as some natural worriers have been pointing out, what if the buried carbon could cause problems?! Do we know our geology well enough to be sure the carbon we bury will stay put?

New research now sets that fear aside. The team led by the University of Manchester has shown through their study that for millions of years carbon dioxide has been stored safely and naturally in underground water in gas fields saturated with the greenhouse gas.

Naturally-occurring carbon dioxide either dissolves in underground water (like Coke) or it reacts with minerals in rock to form new carbonate minerals, essentially locking away the carbon dioxide underground. While much of this has been studied by simulation using computer models, the new study measured the ratios of the stable isotopes of carbon dioxide and noble gases like helium and neon in nine gas fields in North America, China and Europe. These gas fields were naturally filled with carbon dioxide thousands or millions of years ago.

They found that underground water is the major carbon sink and has stayed stable for millions of years.

Of course, one study is no guarantee. And there are other aspects to CCS.

Vaclav Smil, an energy expert at the University of Manitoba, has estimated that capturing and burying just 10 percent of the carbon dioxide emitted over a year from coal-fire plants at current rates would require moving volumes of compressed carbon dioxide greater than the total annual flow of oil worldwide. The economy of scale and the costs are prohibiting.

Retrofitting old plants for CCS would mean laying pipes to carry the gas to nearest aquifers. For new plants the dilemma is whether to build the plant over aquifers or near the fuel source? Either way it spells more costs over pipes, transmission lines, etc. Money which could well be spent on renewables.

But coal is what is available in plenty (relatively), be it in India, China or the US. So how can we simply lump it?? Leave it all to the free market?