Removing carbon dioxide from the atmosphere

There exists a method, or technology, that is capable of reducing the level of carbon dioxide in the atmosphere.

"In practice, the methods consists of capturing carbon dioxide emitted by "climate-neutral" processes such as the combustion of organic waste, pellets or sawdust," explains SINTEF research scientist Mario Ditaranto, a specialist in combustion technology.

It is then stored safely underground for ever, thus reducing its concentration in the atmosphere, because it has been eliminated from the natural carbon dioxide cycle. This is the only method we have to lower the level of atmospheric carbon dioxide, which is an important cause of our climate problems.

The method is called Bio-CCS, and it is not new. Until now it has suffered from a rather mixed reputation as insignificant, expensive and limited in its range of applications. However, in the light of climate change and the recent COP21 summit in Paris, it is on the of everyone in the climatology field. In Norway, it has led to SINTEF, the environmental organisation Bellona and certain branches of Norwegian industry working together for a rapid breakthrough.

"Superlight" geoengineering

The reason for the growing popularity of Bio-CCS is that at the very least it can be regarded as an extremely mild and non-hazardous form of geo-engineering. The aim of geo-engineering is to counteract anthropogenic climaste changes by means of physical interventions. Launching huge sunshades into space and spraying >> millions of ?? tonnes of sulphur into the atmosphere to filter sunlight are a couple of suggestions. These have naturally led to heated debates about both the ethics and safety of such solutions. After all, what might be the consequences if we fix things in ways that only make them worse?

Unavoidable

More than 1000 estimates brought together in the latest report from the Intergovernmental Panel on Climate Change (IPCC) https://www.ipcc.ch/report/ar5/) show that even a significant but gradual brake on carbon dioxide emissions will not be sufficient if we are to avoid a serious climatic crisis.

If we are to stay on the right side of the two-degrees threshold, we will also have to remove some of the carbon dioxide that is already in the atmosphere, and that is where Bio-CCS enters the scene.

In box: If we are to keep global warming within the two-degrees upper limit, we need to be able to remove carbon dioxide from the atmosphere

The blue line in the figure above shows that we will actually need to remove carbon dioxide from the atmosphere if we are to stay within the two-degrees threshold. The red line indicates the climate scenario that we will face if we do not change our habits and continue to emit carbon dioxide at the same rate as today.

Source: Fuss et al., Betting on negative emissions. Nature Climate Change, 4, OCTOBER 2014

Need of negative thinking

"The Paris Summit has made it clearer than ever that zero emissions will not be enough. Even if we stopped all carbon dioxide emissions tomorrow, Earth would still have a climate problem," says Bellona's Marika Andersen, who was among those who followed the climate negotiations in Paris at close hand. Her day job is at Bellona's European office in Brussels, where she works on energy and climate policy, with special focus on bioenergy and carbon capture and storage (CCS).

"We simply cannot avoid using Bio-CCS, which is a solution that Bellona has been promoting ever since 2008. Today, we can see that more and more people are thinking in carbon-negative terms, which is just fine, because carbon dioxide remains in the atmosphere at levels that will have to be reduced," says Andersen.

According to Andersen, we now need to make active efforts to identify partners who are prepared to adopt this technology. For their part, the politicians need to take responsibility for developing infrastructure that will enable industry to deliver and transport carbon dioxide to safe storage sites.

"All this will have its price, though it will be lower than putting out the fire that climate change will bring on if we don't do what needs to be done."

Too expensive, and a source of fear?

But is the world ready to adopt technology based on storing carbon dioxide underground?

Yes and no, says Mario Ditarando of SINTEF, who brings up two factors that have meant that this technology has yet to be adopted on a large scale:

This first is cost. As with all new technology, it needs to be priced in such a way that it can carve out a viable place in the market. It costs a great deal to capture carbon dioxide from electricity generation or industrial processes. Optimistic estimates suggest that energy production will be about seven per cent more expensive than it is today if we capture carbon dioxide from emissions. But it may cost as much as 10 -- 15 per cent more before the technology has been fully commercialised.

We also need to take into account the cost of investing in constructing the capture facility and amortising these over the lifetime of the whole plant. This is a major risk for an energy supplier to take in a market for carbon dioxide-free energy that has yet to be established.

"In practice, this means that society will have to compensate the difference in price between cheap coal and clean energy with CCS. This will require political decisions that have a price in both financial and rhetorical terms," says Ditaranto.

The other factor is human fear, i.e. what the experts call "lack of" public acceptance, which is largely a matter of collective psychology and insufficient knowledge.

"But do we know that storing carbon dioxide in the ground is completely safe?"

"No-one has stored carbon dioxide in the ground for thousands of years, so we cannot be 100 per cent sure that it is completely safe. But the natural gas, of which Norway is the world's third largest exporter, has been safely stored by nature for millions of years, so I am in no doubt that the concept is quite safe. Technically speaking, while there are certainly risks involved, as in all industrial processes, geophysicists and engineers are capable of managing these. We ought really to be more afraid of the climate changes that are on their way. And these are what are going to go off the scale of what we regard as expensive today," he adds, and points to a scenario for the future that could become extremely relevant:

"We can already see how difficult it is in political and economic terms to deal with refugees from war-zones that we can only hope will become more peaceful as time passes. What is it going to be like when the flow of refugees increases because parts of the world become uninhabitable as a result of climate change?"

"What is the difference between "ordinary" CCS and Bio-CCS?"

"The principles involved are identical, but the technology needs to be adapted to suit each individual area of application, and what is just as important, it will have to be tested," says the SINTEF scientist.

One place where it would be useful to start is ethanol production, which is big in both the USA and Brazil, because among other applications, it is used as fuel for vehicles. When we produce ethanol from biomass, pure carbon dioxide is a by-product, which means that we are spared the costs of capturing this greenhouse gas.

"However, we are working on all potential solutions. One important area of focus for us is identifying where it would have the biggest payoffs in terms of technology, logistics and not least, sustainability. In other words, how can we get the most for the climate and our environment out of the least effort, and what are the technological challenges involved," says Mario Ditaranto. For example, bio-waste requires different solutions from wood and sawdust.

Waste pioneers in Oslo

Some big players are already preparing to put these concepts into practice very soon. At the Klemetsrud energy recovery plant in Oslo, for example, Oslo City Council decided in July last year to construct a bio-CCS plant. Last month they opened a test facility that will collect carbon dioxide from parts of the plant, with both the press and politicians attending.

Klemetsrud is currently the biggest emitter of carbon dioxide in Oslo. The plant recovers household and industrial waste from Oslo and several nearby towns and produces almost 6 00 GWh of renewable district heating energy and about 160 GWh of renewable electric power a year. Aproximately 60 percent of the waste is organic. The plant could potentially capture about 400 000 tonnes of carbon dioxide a year, this would make it the first carbon-negative power plant in the world.

These plans have made Bellona rejoice and have caused Johnny Stuen, the City of Oslo's technical director, to roll up his green shirtsleeves:

"We are already going full speed ahead with a feasibility study of full-scale carbon dioxide capture, financed by Gassnova," says Stuen on the phone from London, where he is giving a talk about the Klemetsrud plant.

"We are one of three participants in this study: the Norcem cement plant in Brevik and Yara's fertilizer plant in Porsgrunn also want to adopt Bio-CCS.

"The objective of the study is to design at least one technically and financially feasible carbon dioxide handling chain. For example, it will draw up cost estimates for construction and operation, with a uncertainty margin of ±40%. That part of the work is due to be completed by the summer," he adds.

Facts: The Ministry of Petroleum and Energy will have overarching responsibility for the efforts of the feasibility study. Gassnova will be responsible for capture and storage, while Gassco will deal with the transportation aspects.

The government has stated that they will fund, but it is "open for shared funding" of the Petroleum and Energy department by it's minister Tord Lien. The plan is that the facilities should be operational by the end of 2020.

Wants the politicians on board

On the SINTEF/NTNU campus at Gløshaugen, Mario Ditaranto gazes out over a winter-grey Trondheim.

"Technologically speaking we are a little bit behindhand, because this has not been the most wide-open door for CCS. But now it is time to tell the world that Bio-CCS is the most effective method at hand to do something about the level of carbon dioxide in the atmosphere. By adopting Bio-CCS, we can accelerate the reduction of our carbon dioxide emission," says the SINTEF scientist, adding that the Nordic countries are pretty active in this area: Nordic Energy Research recently funded a research project led by Chalmers University of Technology, in which SINTEF is also a participant. This project aims to look at how biomass can be utilised in one of the most promising CCS technologies, known as Chemical Looping Combustion (CLC).

Ditaranto challenges the politicians to give industry and energy suppliers unambiguous signals that society is now ready to take responsibility, so that the scientists can get on with making Bio-CCS a reality.

Fact-box

Nordic Energy Research funded a project with the name of "Negative carbon dioxide, to be carried out by a consortium led by Chalmers University of Technology that also includes SINTEF Materials and Chemistry, SINTEF Energy Research, VTT Technical Research Centre and Åbo Academy, University in Finland, Sibelco Nordic AB (Sweden) and the Norwegian environmental group Bellona.

The project is based on using biomass as a fuel and Chemical Looping Combustion (CLC), which is a combustion process in which the fuel is kept out of direct contact with air. In its place, a metallic oxide carries oxygen from an air-filled reactor to another reactor that contains the fuel. The only combustion products are water and carbon dioxide, which can easily be separated out by condensing the water.

This is BioCCS

• Biomass, i.e. plants and trees, bind carbon dioxide from the atmosphere as they grow.

• When biomass decays or is burned, the carbon is released to the atmosphere. These two stages thus make up a carbon-neutral circuit.

• If we capture, transport and deposit the carbon dioxide that is liberated when biomass is burned, and store it permanently in the ground, we can actually remove carbon dioxide from the atmosphere.

• The method known as BioCCS is now more than ever relevant as a result of the climate crisis.