In the UN climate panel, the IPCC report describes how we not only need to reduce the rate of emissions but, in the long run, also reduce the amount of carbon dioxide in our atmosphere. This means that we need to capture carbon dioxide. Chalmers conducts research in the field and has reached far. One of the researchers in the field is Henrik Leion, Associate Professor at Chalmers Department of Chemistry and Chemical Engineering.
"We must start catching all carbon dioxide, regardless of fuel. Right now we are working with biofuels. The fossil fuels already work well to capture. The technology for this is available. What prevents us is primarily economy and legislations.
The technique Henrik Leion researches and develops is based on oxygen-bearing solids that replace combustion of oxygen as a gas. His research is part of several projects around a technology called CLC, which stands for chemical looping combustion. In most cases, the heat is generated in power plants through combustion in air. This forms carbon dioxide mixed with another type of gas, depending on technology, and gases are difficult to separate from each other. In order to get as clean a stream of carbon dioxide as possible, CLC uses a solid material where oxygen is included as an oxide, for example ordinary rust. Instead, water and carbon dioxide are created, which are easier to distinguish from each other. When the oxygen on the oxygen carrier is consumed, it is exposed to air and the material is then reoxidized and reusable.
Research at Chalmers within CLC is conducted jointly by several research groups across institutional boundaries. Henrik Leion looks at how oxygen carrier and fuel can be optimized.
As the situation is now, it is not enough to capture only carbon dioxide from fossil sources. Also carbon dioxide from bio combustion must be collected in order to achieve negative net emissions.
"We will need to capture carbon dioxide to a very large extent. Emissions must begin to sink within just a few years, and if we do not do that now, it means that around 2050, we will have to catch more carbon dioxide than we release to compensate for what we did not do 30 years earlier, he says.
CLC is primarily a technology that can work at stationary facilities. Capture involves heavy loads. Not only does the oxygen carrier consist of some kind of metal. The carbon dioxide collected weighs about three times more than the fuel, which in itself would mean increased emissions for a vehicle due to the weight.
Economy and legislation impede
Thus, CLC could be of great use if it was used at commercial level. But yet nobody dares to take the financial risk to invest in the technology. So far, it has been tested in the Chalmers test facility of 12 megawatts with successful results. But a major effort is required for technology to come through, believes Henrik Leion.
“Someone must dare to test the technology in a 50 megawatt facility. This will probably mean losing money initially, but the technology needs this to be further developed, he believes.”
In addition, it must be cheaper to use the technology. The price must be able to compete with carbon credits. Today, a carbon credit, ie the right to release a ton of carbon dioxide, costs about 20 euros. CLC is slightly more expensive, but could, with a bigger initiative, become cheaper. If it is cheaper to collect carbon dioxide than to release it into the atmosphere, chances are that the industry will invest in the technology. In addition, CLC requires that large parts of the combustion system is rebuilt. Another problem is the storage.
"There is no logistics and legislation to deposit carbon dioxide. It takes about 10,000 years for the gas to be converted into limestone. Carbon dioxide is not very dangerous, it is not comparable to nuclear waste, but we talk about huge amounts here, says Henrik Leion.
A legislative problem is the question of liability. Who will be responsible for the storage for 10,000 years? It has also proved difficult to find places where governments and populations accept storage. Another way to store the greenhouse gas is to pump it into drained oil sources at sea. It is expensive and lacks logistics, but it may be necessary.
Must be put into use
Any type of capture technique must be taken into use. Without capture techniques, climate targets will not be reached. What is needed, Henrik says, is that a major energy company dares to test the technology at the commercial level. That company must be ready to lose money. Somewhere, money will probably be lost, but it may be something we have to accept to avoid a significantly higher temperature rise. Without capture, we do not have a chance to stop the temperature rise at 2 degrees, Henrik says who soon will be off for parental leave.
"To be honest, it is frankly not morally easy for me to take a break from the research in this situation. My way of handling my climate depression is to work”, he says.
Text and photo: Mats Tiborn