The collection could be done in more ways than the slightly expensive carbon capture; by oxy-fire using oxygen from the electrolysis, or with an interesting oxy- CO2 firing concept, which I have presented in the figure. Here, oxygen will be diluted with CO2 in relation to transport and storage. Here, too, the majority of the flue gas will be CO2 and energy loss in the capture is avoided. This will make the solution safer and, unlike pure oxy-fire, it can be used in existing installations. In the slightly longer term, efficient high-temperature fuel cells could likely be used with economic benefits [ref: Jacobsen 2023].
With this solution with affordable [SK1]modifications (in relation to hydrogen storage, electrolysis, and fuel cells), it will thus be possible to use the existing infrastructure in the form of the natural gas networks and CHP plants, which is an obvious advantage for minimizing investment costs and accelerating the green transition. The CHP plants even have the right capacity to balance the grid.
The CCS pool is a unwise detour
That we may be able to completely avoid carbon capture at CHP plants makes the government’s CCS pool even more questionable. As a point of departure, the solution by no means supports the ‘wind turbine adventure 2.0’ and that Denmark could become a leader in the development of PtX solutions. The circular carbon will now be sent into the ground and not converted into the green fuels that are in high demand by the transport sector. The transport sector already sees the green transition as a business opportunity.
In fact, with the CCS pool, a technology ‘lock-in’ is made on Denmark’s most important resource and the opportunity to be at the forefront of the PtX race (the biomass). Denmark will find it difficult to compete with really cheap power worldwide. But cheap power does not always colocate with biomass availability, so here we can gain an advantage. Now, the green carbon will just go underground and not do any good...
I would go so far as to say that the CCS pool also hampers the future green transition of Denmark, as this solution is not durable and only makes our society more expensive.
‘Recycling’ plastic—as energy storage
In addition to biomass, we should initially use waste as a supplement to other renewable energy. We must assume that waste will become ‘green’ in the long term. If waste constitutes a valuable energy storage, you could also question the sorting of the garbage into more or less valuable fractions. Plastic has a questionable recycling value, and with the biomass battery concept, ‘recycling’ through combustion and carbon collection may be a more cost-effective solution. We should look into that.
Decommission CHP plants?
The biomass battery makes a lot of sense, as we already have a large part of the existing infrastructure available, i.e. our CHP plants. So we should debate whether we should close down our CHP plants before we get that far. Local Government Denmark (KL[SK2][HF3]) has already formulated a plan for the closure of CHP plants across Denmark.
The plants can be used in the biomass battery concept to provide the necessary storage capacity, but also give our energy grid the necessary robustness.
Thus, CHP plants will hereby not become obstacles to the green transition, but rather a prerequisite for it. The fact that we will be able to balance our energy grid with biomass cheaply is actually vital for the further implementation of other renewable energy sources.
The biomass battery deserves further investigation
In short; the biomass battery is an inexpensive solution, where we recycle our existing infrastructure and avoid the losses incurred by first producing an expensive storage fuel (e.g. hydrogen). It is a solution that we can implement quite fast.
However, the idea is new and in order to succeed, several technical aspects need to be investigated—such as the flexibility of CHP plants, the storage stability of biomass, the possibilities of carbon and oxygen storages, and generally the interaction with other green technologies.
However, if our politicians are serious about the green transition, it seems obvious to investigate these relatively few factors. In my view, there is no doubt that if the biomass battery can be introduced as storage capacity, it offers a huge step forward in ensuring a stable future energy supply. [SK1]Antager, at der menes ”økonomisk overkommelige” [SK2]Antager, at det er Kommunernes Landsforening, der refereres til? [HF3]ja
Gylling, M.; Jørgensen, U.; Bentsen, N.S.; Felby, C. & Johannsen, V.K., (2012). ”+10 mio. tons planen”. Udgivet af Aarhus Universitet og Københavns Universitet.
Graudal, L., U. B. Nielsen, E. Schou, B. J. Thorsen, J. K. Hansen, N. S. Bentsen & V. K. Johannsen (2013). Perspektiver for skovenes bidrag til grøn omstilling mod en biobaseret økonomi: Muligheder for bæredygtig udvidelse af dansk produceret vedmasse 2010-2100. København, IGN/Skov & Landskab, IFRO/Skov & Land- skab.
Emilie Jacobsen, Sofie M. Skov, Alessandro Singlitico, Henrik L. Frandsen, (2023) Techno-economic analysis of green aviation fuel production using an integrated electrolyzer and a “biomass-battery” storage system, International Journal of Hydrogen Energy