Basic information on biogas

1. Composition of biogas produced in anaerobic biogas reactors

Table 1. Average composition of reactor biogas.

Matter	%
Methane, CH 4	55-75
Carbon dioxide, CO 2	25-45
Carbon monoxide, CO	0-0,3
Nitrogen, N 2	1-5
Hydrogen, H2	0-3
Hydrogen sulfide, H 2 S	0,1-0,5
Oxygen, O 2	traces;

2. Landfill gas composition

Table 2. Average composition of biogas recovered at a landfill (landfill biogas).

Matter	Content
Methane, CH 4	54 %
Carbon dioxide, CO 2	42 %
Oxygen, O 2	0,8 %
Nitrogen, N 2	3,1 %
Chlorine (total 2 )	22 mg/ m³
Fluor (total F 2 )	5 mg/ m³
Hydrogen sulfide, H 2 S	88 mg/m³

Calculation of the energy from biogas

Calculation of the thermal value of the recovered biogas (methane 65%)

If reactor produces 2000m³ of biogas per day, the contained heat capacity may be calculated as follows:

Operating efficiency of the utilisation of the produced biogas effects decisively the amount of the energy produced.

• Operating efficiency if only heat is produced - 90 %
• Operating efficiency if both electricity and heat are produced - 85 % (35 % electricity and 50 % heat)
• Operating efficiency if only electricity is produced - 35 %

If a biogas plant uses all the produced biogas for joint production of energy and heat, the amount of energy produced during a day will total 10.94 MWh