Biogas

Question 1

Why are also green gasses key in the energy transition in comparison to renewable energy sources like solar and wind?

Answer 1

Green gasses have a continuous output in comparison to the intermittent availability of RES. These gasses are also more easy to store.

Question 2

What are the 2 key molecules in green gasses?

Answer 2

Methane CH4 and hydrogen H2

Question 3

Why are Biogas and Biomethane green?

Answer 3

The molecule is CH4, exactly the same one as fossil methane, and emits
CO2 during the combustion but CO2 comes from atmosphere since it was absorbed during the growth of the biomass (plants, wood…).

Question 4

What kinds of feedstock can be used for conversion into green energy? How are they converted into energy?

Answer 4

1. Dry biomass: wood, agricultural residues => combustion or gasification (+ methanation)
2. Wet biomass: animal waste, crops, industrial biowaste => anaerobic digestion (vergisting) => gives biogas and can be purified to bioSNG/ biomethane
3. Algae => direct solar conversion

Question 5

What’s the difference between biogas and biomethane?

Answer 5

1. Biogas consists of 60% methane and 40% CO2
2. Biomethane: here CO2 is removed and now consists for the greatest part out of methane => more energy dense

Question 6

What does BMP stands for?

Answer 6

Biochemical Methane Potential: Nm^3 CH4 per ton volatile solid of a specific matter

Question 7

How is biogas produced?

Answer 7

1. Input of feedstock
2. The anaerobic digestion => biogas is formed (1G = first generation)
   3a. Biogas is used as fertilizer
   3b. Biogas is upgraded to biomethane
3. Biomethane can be injected into the gas grid

Question 8

What is 2G bioSNG? How is it produced?

Answer 8

Dry biomass is used as feedstock, containing carbon. A pyro-gasificationprocess aims to convert the biomass in a synthetic gas = syngas rich in CO, H2, CO2 and CH4. Then the syngas is purified by removing undesirable compounds such as tars or inorganic sulfur. Next catalytic methanation aims to increase the carbon conversion into methane. Finally the gas is upgraded to the desirable quality according to its usage.

Question 9

What are challenges for the production of bioSNG?

Answer 9

1. Flexibilty in biomass procurement (inkoop)
2. Improvement of the gasification process (efficiency, quality, availability, …)
3. Innovation for syngas purification process, CAPEX and OPEX reduction and reduction of environmental impacts
4. Definition and validation of the methanation process, catalyst performance and lifetime improvement and the integration of the process