Capturing carbon

The Sleipner gas field in the Norwegian sector of the North Sea.

Since 1996 the Sleipner field in the Norwegian sector of the North Sea has been capturing about one million tonnes of CO2 each year and storing it in a saline formation 1 km below the seabed. So far more than 20 million tonnes of CO2 has been captured, equivalent to the annual emissions from ten million cars. Credit: Øyvind Hagen/©Equinor

Carbon Capture and Storage offers a way to take greenhouse gases from industrial plants or power stations at source and storing them to prevent release into the atmosphere.

Carbon dioxide is the most damaging of the greenhouse gases responsible for the current era of climate change. And it is emitted in bulk by power stations, chemical works and other industrial plants. As a result, the idea of capturing it at source and storing it underground in stable geological structures, for thousands if not millions of years, is an appealing one. 

Known as CCS for Carbon Capture and Storage, this technology is now being pursued by the European Carbon Dioxide Capture and Storage Laboratory Infrastructure (ECCSEL), established in June 2017 as a European Research Infrastructure Consortium. The British Geological Survey, part of UKRI NERC, is a principal UK participant.

ECCSEL is led from Trondheim, Norway by Sverre Quale, an engineer with long experience of aviation and railways as well as the oil and gas industry. ECCSEL exists, he says, to make sure that the big facilities and equipment needed for CCS research and development are available to researchers across Europe.

Most are in national research labs and major universities. As he says: “It is a waste of money for everyone to invest in their own and often overlapping facilities. Here and in other areas of research, it is better to work more collaboratively.”

Quale points out that there are four major elements of CCS – the capture, transport, storage and possible utilisation of carbon dioxide. There have been big pilot projects of all these phases. Commercial equipment is now available to allow new and existing plant to capture carbon dioxide, and can be added to existing installations in a few months.

In addition, the technology for injecting carbon dioxide into geological structures has been demonstrated at the Sleipner and Snow White gas fields in Norwegian waters and elsewhere. “At its peak,” says Quale, “Sleipner was storing up to a million tonnes of carbon dioxide per year, and it is still running at about half that.”

There is also geological modelling of underground reservoirs which shows that they will hold carbon dioxide stably for long periods of time.

Alongside these storage options, there is also the intriguing prospect that captured carbon dioxide might be put to use. Quale points out that it is already used as an additive to the air in greenhouses to encourage vegetable growth. It is also injected into oil wells to increase the pressure and so keep the oil flowing, a process called Enhanced Oil Recovery. This use, he says, has “driven the development (of CCS) in oil regions in Canada and the US.”

But Quale agrees too that despite this potential, there is now a perception that CCS has stalled as a growth technology. “In the past two to five years, many countries have announced that they plan to stop using coal, as well as oil in the longer run, and especially in Europe. So it has not been easy to promote and fund CCS while the focus is on replacing fossil energy with renewables.”

However, Quale adds that this is only part of the story – 20-30% of carbon emissions come from steel and cement works and from other big industrial users. This is good for CCS. He says: “It is very hard for these plants to get to zero carbon without CCS. This is now the focus for collaborative industry projects in the UK, Norway and the Netherlands.” 

Part of the picture is Norway’s Northern Lights project, which involves Shell and Total. Here ships and pipelines will be used to transport carbon dioxide for offshore storage underground by energy group Equinor.

One key part of the picture, thinks Quale, is for fossil fuel users to start paying a realistic price for every ton of carbon they emit, perhaps two to three times the current level in the EU Emissions Trading System. Norway’s higher carbon price has been a key factor in its CCS story, for example making the Sleipner project viable.

But even in today’s policy setting of support from EU and National Governments, Quale expects to see more deployment of CCS in three to five years. The research and development now taking place will drive down costs, making far more CCS projects attractive. He expects too that Germany will soon get involved in CCS and ECCSEL, despite public objection to carbon storage below ground onshore in Germany.

He adds that Greenpeace has opposed CCS as a Trojan Horse for fossil fuel use. He is convinced that these objectors are wrong. “It is impossible to get to 100% renewables,” he thinks. “The timescale is too tight without CCS.”

Lucky rocks

Jon Gibbins is professor of carbon capture and storage at the University of Sheffield, and director of the UK CCS Research Centre. He insists that Britain has a major role to play in the deployment of CCS in Europe, and says: “Carbon capture is essential if we are to get to zero emissions by 2050. Other approaches will take you part of the way, but only carbon capture will get you to zero and let you carry on using fossil fuels.” 

He adds that geological good luck is part of the reason for the UK’s CCS leadership. “We have about half of Europe’s capacity for storing carbon dioxide (in deep strata). Norway has most of the rest.” 

In addition, the UK has industry that can connect to a future carbon sequestration system. The UK government is now putting around £1bn of direct funding into the technology, plus planned additional support through clean energy incentives.

In Gibbins’s opinion as an engineer, the technical fundamentals of carbon capture  are mainly solved – it just needs development at scale. Instead, the problem is that governments have yet to face the reality of reaching net zero carbon emissions. Most current policy, he says, is based on reducing, but not totally cutting, fossil fuel use. This approach “only takes you so far.” 

Carbon capture, however, allows nations to go to zero emissions, and even beyond. Carbon can be captured from power generation, industry and other sources. But in addition, Gibbins points out, a plant is now being planned in the US to extract a million tonnes per year of carbon dioxide from the air. He says: “This is transformational. It allows you to go beyond net zero emissions and into negative ones.”

Like Quale, Gibbins is aware that this technology has its opponents, including some who object to it as a form of geoengineering. He says: “It is geoengineering to put (fossil) carbon dioxide into the atmosphere in the first place. But why do people object to taking it out again?”