Production of biogas with CCS in Norway

Abstract

Crude biogas from anaerobic digestion contains CO2 at approximately 36% concentration. This CO2 would normally be released into the atmosphere during upgrading of biogas to biomethane. Alternatively, these emissions can be avoided by capturing the CO2 and storing it permanently in geological formations (CCS). Production of biogas can contribute to negative CO2 emissions if combined with CCS. The IPCC Fifth Assessment report* by the Intergovernmental Panel on Climate Change suggests a potential range of negative emissions from biogas plants with CCS of 0 to 22 gigatonnes per year. Depending on volumes and location of the biogas facilities, additional costs related to implementation of CCS can be relatively low. The infrastructure can be retrofitted to existing facilities or integrated into the design of new facilities. This way, CCS can represent an additional climate upside for biogas production.

The study performed by Carbon Limits with the support from CLIMIT (national research program in Norway for CCS technologies)† and in collaboration with the Norwegian Environmental Agency examined the costs of implementing CCS at biogas plants in Norway. The study also investigated the measures which could support the implementation of CCS on biogas plants. The analysis was performed for a reference biogas plant. The capacity and operational parameters of the plant reflected the realistic conditions and were derived from the analysis performed by Carbon Limits on the Resource base for biogas production in Norway in 2030‡. In addition to the reference case, the analysis covered a case study performed for the Bekkelaget treatment plant located in Oslo. The plant upgrades approximately 23 GWh/year of biogas to biomethane. This is 23% of the reference plant capacity and corresponds to 2,500 tonnes of CO2 emissions annually.

Transport and storage provider for both the reference case and the Bekkelaget case study was assumed to be the Northern Lights§. It may be one of several players offering transport and permanent storage of CO2 in Norway but so far, they are the only project in Norway which has started construction of its facilities. Northern Light's estimates for CO2 transport and storage services were therefore used in the study as a basis for collecting CO2 from Norwegian ports and their tariffs were included in the cost estimates for the entire CCS value chain.

The transport of CO2 from the biogas capture facility to the port was assumed to happen by CO2 trucks. Truck transport requires CO2 to be in the liquid phase. CO2 liquefaction also helps to meet purity requirements for Northern Lights. Water, oxygen, methane and other unwanted components can be removed efficiently during the liquefaction process. The standard transport conditions for CO2 today are 17 bar and -25 0C. Costs of liquefaction and truck transport were also accounted for in the cost estimates for the CCS value chain.
As a result of the study, the additional cost of CCS on the biogas facility in the reference case was evaluated at 108 EUR/tCO2. For the Bekkelaget case study, despite the short distance to the port, the cost of CCS would increase to approximately 121 EUR/tCO2 due to the smaller size of the plant compared to the reference case.

The study concluded that the biogas production in combination with CCS can be an attractive climate measure to generate negative emissions. A combination of CO2 sources with higher CO2 concentration and available storage provider in Norway (Northern Lights) contribute to lower costs, while relatively small and scattered biogas plants contribute to increased costs. When it comes to the support measures for the biogas plants with CCS, the negative emissions that these facilities accumulate are not included in the Norwegian emissions accounting system, and do not count towards the achievement of the common climate goals and climate commitments between Norway and the EU. The EU is currently working on various processes related to accounting of emissions reductions from biogas production with CCS, and it is conceivable that relevant instruments will be introduced both at EU and at national level. Until then income from voluntary schemes is the most relevant incentive to fund such facilities.

Keywords: Biogas; carbon capture and storage; CCS; value chain; CCS cost; Norway