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Time for underground CO2 storage is now, advocates say

by

Staff Writer

From renewable energy, fuel cells and electric vehicles to energy-efficient home appliances, people have found ways to reduce greenhouse gas emissions to mitigate climate change.

One technology expected to play a key role in curtailing emissions is carbon dioxide capture and storage, commonly known as CCS.

The process entails separating and collecting carbon dioxide, including exhaust emitted from thermal power plants, and injecting it into deep underground storage cavities so the carbon dioxide won’t be released into the atmosphere.

Hundreds of millions of tons of carbon dioxide could potentially be buried underground, but the technology is still in the experimental stage in Japan. At this point it’s both extremely costly and not an easy sell to a nervous, earthquake-wary public, preventing its widespread introduction.

Yet experts stress that CCS is essential if the world hopes to get serious about curbing greenhouse gas emissions.

“The costs are steep, but carbon dioxide emissions must be reduced,” said Japan CCS Co. President Shoichi Ishii.

Established in 2008, Tokyo-based Japan CCS is funded by regional utilities, oil firms, engineering companies and trading houses as part of an industrywide effort to promote underground carbon dioxide storage.

The CCS process starts with capturing carbon dioxide from exhaust gases, such as thermal power plant emissions, that include other substances like oxygen and nitrogen. There are several ways to separate carbon dioxide, but the most common one is to absorb the gases in an amine solution. Heating this solution renders the carbon dioxide into a highly pure state.

Once extracted, the pure carbon dioxide, now in a “supercritical” gas-liquid state, is transported to locations where it can be injected through pipes into the ground to a targeted geological layer more than 1,000 meters down.

The injected carbon dioxide is initially lighter than water so it floats to the top of the underground formations but stays there because it can’t permeate upper layers of densely packed rock and soil, just like deep underground oil deposits that are unable to seep to the surface even if they are floating atop groundwater and being pushed against the roofs of sunken cavities.

In a process that will take hundreds of years, the carbon dioxide dissolves into its underlying salt water or flows into tiny cracks in rocks to become mineralized.

At the government’s request, Japan CCS has been carrying out an experiment in Tomakomai, Hokkaido. Starting in 2016, it plans to inject 100,000 tons of carbon dioxide underground per year at the site over a three-year period, with the goal of achieving practical use of the technique by 2020.

The CCS approach is costly, offering little economic incentive for private-sector firms seeking to eke out a profit unless they are under government contract.

The Kyoto-based Research Institute of Innovative Technology for the Earth (RITE), which studies environmental issues, estimates it would cost about ¥7,300 to store 1 ton of carbon dioxide via the CCS method.

According to figures from the Environment Ministry, Japan emitted about 1.3 billion tons of carbon dioxide in fiscal 2012. It would thus cost about ¥950 billion to store just 10 percent of that level of annual output, under RITE’s estimate.

Among the emitters that could potentially have the financial heft to utilize carbon dioxide capture and storage are large-scale facilities like thermal plants and factories.

RITE believes Japan has the capacity to store 150 billion tons of carbon dioxide underground.

Advocates say that the world has seen the dramatic, and harmful, impact of global warming in recent years and thus should not consider the pursuit of the CCS process an extra financial burden.

“Nobody thinks of (their municipal) garbage collection service as (an unnecessary) expense. It is funded by tax money. People welcome the service because they don’t want garbage piling up at their home,” said Kozo Sato, a professor at the University of Tokyo and an expert on the CCS approach.

The world won’t get serious about reducing carbon dioxide emissions unless people regard the gas as household garbage that has to be hauled away, Sato said.

If humankind chooses to take no effective steps to reduce carbon dioxide emissions and accepts global warming as inevitable, CCS would be unnecessary and the world should focus on coming up with defenses against the consequences of climate change, he said.

But at least for now, the world is aiming to cut greenhouse gas emissions.

The International Energy Agency has estimated that CCS is expected to account for 19 percent of global carbon dioxide reductions in 2050.

Sato argues that if the world intends to cut emissions, CCS is the path to follow.

The technology has been in practical use overseas for years, so it’s a matter of how serious people get about promoting CCS, he said.

Also, the public must be on board, experts say, noting that people living near planned storage sites must be convinced they are living in a safe environment.

People in Tomakomai were initially worried that the CCS experiment would be dangerous, Ishii said.

“Many people are unfamiliar with CCS and thus conjure up notions of radioactivity or carbon monoxide,” he said.

But Japan CCS eventually gained the community’s acceptance and relations are now good.

Another concern is that injecting carbon dioxide underground could cause earthquakes.

Ziqiu Xue, chief researcher at RITE, said it is true that injecting carbon dioxide underground could cause small-scale shaking episodes, but “they are very small. Humans feel (an) earthquake when it is about magnitude 3, but those (caused by CCS) are smaller than magnitude 1 (and are not felt by humans),” he said.

There have been no reported large-scale earthquakes induced by CCS projects anywhere in the world, he said.

Shaking occurs when the carbon dioxide is injected into the targeted layer and bonds that hold grains of sand together are broken due to the change in pressure, Xue said.

But the energy created from a carbon dioxide injection is small amount compared with the massive amount that would be required to trigger a large-scale temblor or other tectonic upheaval, he said.

Some people may also worry about the consequences should a massive amount of stored carbon dioxide somehow escape to the surface, because such a high concentration could cause carbon dioxide poisoning and have other harmful effects.

To prevent this, Ishii said it is critical to choose a site and geological layer that can definitely trap carbon dioxide underground, and strict monitoring will be essential so that operators can quickly take measures if they detect leaks.

Sato of the University of Tokyo meanwhile said storing carbon dioxide underground is not so extraordinary.

“Natural gas found underground contains carbon dioxide. This is common,” he said, adding that the carbon dioxide found in the Natuna gas field in the South China Sea is about 70 percent pure.

This section features new technologies that are still under research and development but are expected to hit the market in coming years.

  • Philip Haddad

    The effort to capture and store CO2 is misguided and counterproductive. First, CO2 is not the major anthropogenic contributor to global warming. The major cause is the heat emissions released from the combustion of fossil fuels,(and from nuclear power plants which emit three times the total heat as their electrical output). These emissions contain more than four times the amount of heat accountable by the air temperature rise. These increased 20-fold during the 20th century and as the temperature gradually rose so did the CO2 since 80% of our energy use is supplied by fossil fuels. From 320 ppm in 1965 to over 400 ppm at present, there is no point at which CO2 became the CAUSE of global warming. The goal of 100,000 tons a year is insignificant. To reduce CO2 concentration by 1 ppm requires the removal of 9 BILLION tons. (At what concentration of CO2 will the EPA say the “Carbonic Plague” no longer threatens human health?) We are continuing to add tens of billions of tons a year through use of fossil fuels. The only answer, even if you question “is it heat or CO2″ is the replacement of fossil fuels with renewable energy such as solar, wind, etc. This will take time and investment and must be encouraged. Taxing either heat or CO2 will only increase cost of energy. We cannot trust governments to use the taxes for the express purpose of expanding renewable sources

    • Starviking

      Do you have any scientific references for your claim that power plants are the major factor in warming the earth, not greenhouse gasses?

      • Philip Haddad

        Starviking: I have just presented the only scientific reference that even acknowledges the impact of heat emissions. I have a PhD in Chemical Engineering and have calculated that with an energy consumption of 16 terrawatts enough heat is emitted (50x10E16 btus per year ) to heat the atmosphere (mass of 1166x 10E16 pounds and a specific heat of 0.24) by more than four times the actual measured rise in temperature. This is only an addition of 0.028 watts/sq.meter but is enough to upset the thermal balance that existed before the 20th century. This is not only from power plants but any facility that burns fossil fuels like most of our transportation.The increase in the effectiveness of greenhouse gases due to a 30% increase in CO2 is probably minor as compared to the 20-fold increase in heat emissions for the same period. The greenhouse gas not only slows the release of solar energy but also holds back the release of ordinary heat from combustion of fossil fuels or from cooling water or air used in nuclear power plants, or other industrial plants. The Kyoto scientists studying the cause of global warming used the correlation of CO2 and temperature rise to correctly determine that fossil fuels were a major contributor, but neglected to consider that the heat emissions could also be correlated with temperature rise. Al Gore’s “An Inconvenient Truth” made global warming a recognized problem, but unfortunately cast in concrete the idea that it was due to CO2 alone. The IPCC simply amplified that perception. There are NO correlations of CO2 and temperature for which it can be shown that CO2 is a cause and not a result of a third contributor. I look forward to your response.

      • Starviking

        Hi Philip,

        your waste heat forcing agrees with Professor Mark Flanner’s figure from his 2009 paper, “Integrating anthropogenic heat flux with global climate models”.

        However, Greenhouse Warming’s net forcing sits at around 2.9 W/m2, so waste heat – at less than 1% of that value – is negligible at present.

      • Starviking

        Hi Philip,

        your waste heat forcing agrees with Professor Mark Flanner’s figure from his 2009 paper, “Integrating anthropogenic heat flux with global climate models”.

        However, Greenhouse Warming’s net forcing sits at around 2.9 W/m2, so waste heat – at less than 1% of that value – is negligible at present.

      • Philip Haddad

        Comparing waste heat flux versus the TOTAL greenhouse forcing is only slightly less disingenuous than comparing it to the total solar input. We are not concerned with the totals, but the change in each heat source during the past century. I don’t know, nor probably does anyone else know how much the Greenhouse Warming’s forcing has changed during this period. We do know how much waste heat emissions are and that they are of a magnitude that correspond to the changes that we measure. If the change in Greenhouse Warming is not known, it has no place in the discussion. The artificial determination of CO2’s effect on temperature is based largely on the assumption that a rise in temperature was caused by a rise in CO2 but there are no correlations for which it can be shown that CO2 was causal. Thanks for the reference to Professor Flanner”s paper. I will check it out later. Thanks for your response.