Biogas is produced by the microbial decomposition of substances under anoxic conditions. It consists of approx. 54 % methane and 40 % carbon dioxide (CO2).
CO2 is colourless, odourless and is produced, for example, during the combustion of carbon-containing materials, during the production of fertilizers and during fermentation.
What conditions do I need to meet in order to sell my LCO2?
Impurities pose a problem in the utilization of CO2 from biomethane. A European industry standard was created specifically for this purpose. This was created by the European Industrial Gases Association.
The standard (EIGA DOC 70/17) regulates limit values for impurities in the ppm range, origins and verification. The Eiga standard also requires food safety risk analyses and food safety management systems, which also include the fermentation of substrates. In accordance with the legal requirements, every supplier should introduce a Hazard Analysis Critical Control Points (HACCP) system. This hazard analysis determines critical control points (EIGA Doc 70/17, European Industrial Gases Association AISBL).
What are the marketing criteria for my liquid CO2?
- The composition >99.97% CO2 by volume
- Food quality according to EIGA 70/17
- Pressure approx. 20 bar (g)
- Temperature approx. -30 °C
- Pressure dew point > -55°C
How does CO2 treatment and transportation take place?
The CO2 is collected during biogas treatment, purified and liquefied using a CO2 plant.
A compressor is required for the liquefaction process, which compresses the CO2 to such an extent that it changes into a liquid state.
The CO2 can then be supplied to industry in special tankers for further use instead of being released into the atmosphere unused.
What are the financial benefits of CO2 capture and LCO2 production?
For the sale of CO₂ to be financially viable, market participants should produce at least 2,500-5,000 t/a and take the market environment into account. If the purchase is from a regional bulk buyer, prices of up to €50/t can be achieved. It should be noted that, compared to the winter months, there is a significantly higher demand for CO2 from bulk buyers on the market in the summer months. This is due to increased consumption of, for example, carbonated drinks, dry ice and refrigerants.
How are emission savings achieved by capturing and reusing carbon dioxide?
The CO2 reduction is referred to as the greenhouse gas reduction quota (GHG quota). Fossil fuel producers are legally obliged to reduce their greenhouse gas emissions. If they cannot achieve this to the required extent, they must pay penalties as compensation. This is shown as a percentage and explains the placing on the market of sustainable fuels in relation to the total quantity (including fossil fuels). The current GHG quota is 7% and is to increase to 25% by 2030 within 8 years(https://ibbk-biogas.com/thg-quote, 11.08.2022).
What role does the Renewable Energy Directive II (Red II) play?
The types of substrates fed into the biogas plant play an important role in the remuneration. Care should be taken to ensure that not only renewable raw materials are used; advanced substrates such as liquid manure/dung should be used. RED II defines whether it is a sustainable biofuel.
If CO2 is captured and liquefied (Carbon Capture Utilization, CCU/ Carbon Capture Recycling, CCR) or geologically stored (Carbon Capture Storage, CCS), a bonus in the form of negative emissions is added to the GHG balance. For example, the average GHG value of slurry/manure is -100 g CO2/ MJ. If CO2 liquefaction is also used, a further -30 to 50 g CO2/ MJ is taken into account. An individual calculation of the savings often makes sense here.
