Scientist: ‘I’m pretty sure we will need carbon removal technologies’

Technologies like Direct Air Capture (DAC) are likely to stay small-scale for the time being, says Nils Røkke, who calls for a research and innovation agenda for negative emission technologies at EU level. [Climeworks / YouTube]

Sucking CO2 from the air to mitigate global warming may sound silly at first, but it’s likely to be necessary nonetheless, says Nils Røkke. And the more we delay it, the higher will be the demand for carbon removal technologies in the future, he warns.

Nils Anders Røkke is a Norwegian scientist and business leader. He is the executive vice president for sustainability at SINTEF, the largest Norwegian research institute. As of May 2017, he has been the chairman of the European Energy Research Alliance, the research pillar of the EU Strategic Energy Technology Plan.


  • Negative emission technologies can never be used as an excuse to delay renewables, energy efficiency, and other clean energy solutions.
  • The issue with all of them is the huge amount of resources that are needed to bring them up to scale – whether it’s land for biomass with CCS (BECCS) or clean electricity for Direct Air Capture (DAC).
  • However, carbon removal technologies will probably still be needed to deal with emissions that cannot be entirely eliminated by other means.
  • That’s why Europe should put in place an innovation and research agenda, with more funding, to develop negative emission technologies.


Most IPCC scenarios now include negative emission technologies like Bioenergy with Carbon Capture and Storage (BECCS). Why is that? Is it because BECCS is considered the most mature?

Yes, it’s because BECCS uses more or less the same technology that has been worked out for coal, oil, and gas. The flue gas is slightly different but basically, it’s the same thing.

The issue with all carbon removal technologies is the resources needed to bring them up to scale. BECCS, for instance, implies a lot of biomass. Some of the IPCC scenarios point to related land use with BECCS that is equivalent to the forest area of Russia. And that’s huge.

So you’re saying BECCS cannot work because the amount of land that’s required would be too big anyway?

Well, I think it’s doubtful that we’ll be able to dedicate all that land area to sustainable biomass production. Look at the IPCC report on land use that was published in August, it shows quite clearly that we’re using more land than we should.

You’re ruling it out, in a way…

No, I’m not ruling it out. There is potential for bio-CCS, for example in waste-to-energy plants. If you take care of the CO2, then that removes carbon from the atmosphere. It’s just the amounts needed which are going to be very hard to achieve.

What is missing also in the scenarios for bio-CCS is the possibility to use biomass from the ocean-seaweed, macroalgae and the like. There is a huge untapped potential there and it is missing in all the carbon removal reports and assessments. We need to look into this opportunity.

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The other technology is Direct Air Capture (DAC), which has been pioneered in Switzerland. How do you evaluate the potential there?

It works but there are issues about scale. DAC plants need a lot of electricity, which has to come from renewable sources in order to make the process carbon negative. So I’m not sure this is feasible to do it at scale and for a price which is socially acceptable.

How much electricity is needed for DAC? Can efficiency be improved or would you rule it out for the time being as a credible negative emission technology?

It can be improved. Look at Climeworks in Switzerland, they showed it can be improved. But it’s really important that it reaches the commercial stage. The captured CO2 can be sold as a technical gas, for use in greenhouses or for beverage production, and that’s already happening now.

But it’s likely to stay small-scale for the time being. So there is potential in negative emission technologies (NETs). But the amount of renewable electricity or biomass that’s needed is putting some constraints on these.

That means you really need to develop all the mitigation actions. NETs are really a last resort option. And Direct Air Capture (DAC) can make sense in that context.

You’re referring to the ‘moral hazard’ related to negative emission technologies: they can provide an excuse to delay emissions reductions or keep burning fossil fuels…

Negative emission technologies can never be used as an excuse to delay solar, wind, efficiency, CCS and other solutions.

It’s a last resort technology but I’m quite sure we will need it. Nowadays, emissions are increasing rather than decreasing, and we are unlikely to turn around this pattern in time to reach the targets of the Paris Agreement.

You can say it’s stupid to clean up CO2, which is highly diluted in the air, rather than stopping emissions before they go out in the atmosphere. But there is so much inertia in the climate system and so much momentum behind polluting emissions that this is unlikely to change overnight.

So I’m pretty sure that we will need this. And all the reports from the IPCC, the IEA, the Royal Society, etc., show that some emissions will be unavoidable, for example in process industries and from agriculture, which have to be offset.

And the more we delay the moment at which emissions decrease, the higher will be the demand for these technologies. We should never see them as a fix to carry on emitting CO2 as we are doing now.

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What about Solar Radiation Management (SRM), where aerosols are sprayed in the high atmosphere to divert solar radiation? Is this a promising technology in your view?

It’s pretty speculative, it’s trying to mimic natural process. The major problem, I think, is that it does not remove any CO2 from the atmosphere. So it doesn’t fix that fundamental problem of CO2 concentrations which is also causing ocean acidification.

That’s why I see this more as a kind of ‘patch’ technology. But again, you may need that as well, as a last resort.

It’s the last resort of the last resort, in a way…

Yes, but that doesn’t mean we should dismiss it either.

Should we start planning for them now?

I’m pretty sure we will need carbon removal technologies to deal with unavoidable emissions, for example from agriculture, that need to be offset.

Of course some of those emissions can be reduced but they probably can’t be eliminated entirely and we will need carbon removals for the rest.

The problem is that we don’t have a research policy for this. And I’m concerned because the IPPC put carbon removal technologies in most of its scenarios, even though it’s not well thought through.

We need an innovation agenda for that.

How much do you think the EU should invest in research around CO2 removal technologies?

The EU’s last research and innovation programme had a budget of around €70 billion and the new one will hopefully be above €100 billion. Of this, there is a small part dedicated to carbon removal technologies, around €10 million per year.

This is too small in my view, in relation to the challenge. This is why we’re calling for an innovation and research agenda for these technologies – in Europe and on a global scale.

All these technologies have one thing in common: they need a place to store the carbon or the CO2, for example as a liquid in depleted oil and gas fields, like we’ve done in Norway for years.

And there is also pyrolysis, where hydrogen is produced from natural gas – in principle without oxygen-producing solid carbon-hydrogen. The solid carbon can then be used in products with a closed CO2 emission lifecycle or buried in the soil, acting as a fertiliser.

This is also being researched for pyrolysis of biomass. Growing trees, harvesting them to make biochar and then returning the carbon to the soil is a complicated process but it should not be dismissed either. With the amount of carbon removal needed, it may make sense and could change the way agriculture and forestry are conducted in the future.

What has up to now been called silly technologies and processes may become absolutely necessary if we don’t stop acting silly.

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[Edited by Zoran Radosavljevic]

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