Monday, 7 October 2019

Carbon capture and storage: Realities and myths

In the same year my father died, when I was still living in southeast Queensland, I was asked to attend a conference to write stories for use in a company’s in-house communications. I still have a friend who works for this company, which makes instruments, systems and software used by many different industries, including construction, refining, petrochemicals, and mining. I haven’t seen him for many years.

Meetings such as the one I travelled to give people who work in companies that use the technology provider’s products an opportunity to learn about new product offerings, to talk with peers, to learn about government initiatives, and to learn about new research. People also go to them to have fun and, on the final night, there was a fancy-dress party. I didn’t go to the shindig and spent most of the time outside work hours in my room in the hotel transcribing recordings and writing up the stories I had been commissioned to produce. I was reimbursed money for the plane fare, and for other travel expenses, and was paid for the story drafts I submitted but I don’t know if all of them were used.

I started this blog in 2006 and so, for many years, had been vocal in favour of causes I took an interest in. At the time I was also taking commissions for stories from magazines including Australian Anthill (which focuses on entrepreneurs) and Ethical Investor (which had been founded by Australian journalist Paddy Manning and which ran stories about innovations allowing companies to do business and at the same time minimise their impact on the environment). The woman in the technology company’s comms role, who asked me to go to the confab, doesn’t work there anymore. I was never asked to cover another conference held by the company.

In what follows I will anonymise people’s identities. Note that it describes the state of the art almost a decade ago. However if, in the intervening years, someone had discovered an affordable method of capturing and removing the carbon that exists in the emissions of industrial plants, we would surely have heard about it by now. Constant reminders in the media from some sectors of the community about the potential of CCS indicates that it still remains a hope for many. But the problem with CCS is that it is not feasible and I will show why that is so.

One man who spoke at the confab worked at the time for a Commonwealth research agency that had been established under Tony Abbott’s leadership and that is still operating. I shall call him Mark although that is not his real name. He had worked for an Australian petroleum company and is now associated with a privately-funded research centre that helps gas producers.

“The first part of the chain is to capture the carbon,” Mark told seminar attendees, who were seated in a room in the hotel the event was held in. “We’re talking about the capture from anthropogenic sources, man-made sources. The most common examples we have tend to be emissions from power stations, iron and steel plants, fertiliser plants, natural gas processing plants.”

There existed, at the time the conference was held, examples of carbon capture installations at gas processing plants in the United States and offshore Norway, and at fertiliser plants in the US and Canada. Offshore of Western Australia there were plans afoot, Mark went on, to realise an installation at the Gorgon gas project located off the coast of Western Australia (construction of this plant was completed in 2017, so well after the confab had finished).

“Where we do have an issue in terms of technological development, is the application of CO2 capture at scale to industries like power generation, iron and steel, cement, pulp and paper,” Mark said. “It’s been worked out at lower scales, smaller scales. Not at large scale.” The requirement is to take the application from where it is mature into industries where it is still to be proved, Mark said.

He asked, rhetorically and to make a point, why CCS is important for businesses. “One scenario that has been painted by the International Energy Association takes the storyline, ‘If we don’t do anything from this point on and we live in an as-is world, by the time we get to 2050 annual emissions will have doubled, roughly.’”

Global annual CO2 emissions were expected (at the time of the conference) to increase from 28 gigatonnes to 56 gigatonnes. To keep current CO2 concentrations in the atmosphere constant up to 2050, it would be necessary to halve emissions, Mark said. “We’re talking about, in this particular scenario, it’s almost like a new industrial revolution in the way we use energy.”

Around one-fifth of the reduction would be due to the implementation of CCS. “It is part of a suite of measures on climate change,” said Mark. “Just being smarter with what we do now, which actually is the major contributor.”

In August 2007, the House Standing Committee on Science and Innovation had tabled a report on an inquiry into geosequestration technology. The report says there are three ways to capture carbon: post-combustion, oxyfuel combustion, and pre-combustion. It goes on:
There are a range of views on the suitability of each of these technologies, particularly in the Australian context. There is some agreement that post-combustion capture is the process most applicable to Australia’s current stock of power stations. There is also general agreement that the focus of research and development should be on the technologies that can be applied to the existing power stations.
On the day before Mark made his address at the conference, I spoke with Karush (not his real name), a migrant from the Middle East who graduated from one Group of Eight university and now works for another. Karush had won a competition, run by the company that held the confab, for research into carbon capture in power plants. He did this by simulating plant operations on a computer.

The academic who supervised Karush’s work, who I will name Omar, said to me, “The project is about improving the efficiency of power plants once they are integrated with carbon capture processes.”

“The carbon capture process is introduced to remove the CO2 from the power plant and purify it, separate it, and compress it downstream and into the geosequestration,” Omar went on. “There are many issues with this implementation.” (Geosequestration is the process of burying CO2 in geological formations in a liquid form as a dense supercritical fluid.)

The power industry, Karush told me, had been focusing its efforts to prove a carbon capture technology using absorption technology, although this is only one of the available methods of removing CO2 from emissions. Absorption had been used in the oil and gas industry for decades, said Karush, but at a larger scale it is still an emerging technology.

“In small scale this technology has been developing over maybe three decades. When we go for PCC [post-combustion capture] we have something, it’s not fully available, but it is the best one and industry can at least say, ‘I will take this one and go to the next stage of making it large-scale,’” said Karush.

In power plants, flue gas is channelled to an absorption system where solvent is added to the stream and binds to the CO2. The solvent is then taken to a regenerator where the CO2 is separated from it, so that the solvent can be reused. The energy required to separate the solvent from the CO2 is, currently, “huge”, said Karush.

“I always use the analogy to make it quite simple,” said Omar. “It’s like a pregnant woman. The power plant is the woman, now pregnant with the baby that is the capture plant. It’s a burden. The case here is that the baby is estimated to be the same size as the mother. The capture plant is estimated to be the same size as the power plant.”

Heat must be taken from the steam cycle to feed the regeneration system where the solvent is separated from the CO2. “We need to extract steam, which we are using to generate power,” said Karush. “[And] we need to bring that steam just to add heat to this reaction. Overall the efficiency of the power plant and the power output decreases notably.”

Karush’s simulation had shown that an 18 percent overall improvement in efficiency could be achieved in such a plant. Keep in mind that this was just achieved through computer modelling and hadn’t been reached by studying an implementation of technology installed in a working plant. And even an 18 percent reduction in energy used by emissions scrubbing equipment is not enough to make CCS feasible.

But as the conference progressed it occurred to me that people in these industries, listening in the scheduled information sessions and chatting with engineers stationed around the product display room, would see Karush’s research as a promising sign. Still “early days”. The work would go on. Given the nature of the influence working on many industries to comply with community expectations that they will operate in a way that minimises impacts on the environment, it is no wonder that there is so much work being put into CCS. But the challenges facing researchers and managers are enormous.

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