Costs of biogas upgrading into biomethane are estimated at $7/mcf off of capex cost of $400/ton, in this data-file. The largest contributor to total costs is carbon filtering, to remove siloxanes, VOCs and H2S, which we have modelled from first principles, at $2/mcfe. Underlying data into biogas compositions and impurities are also tabulated for reference.
Biogas is a mixture of 40-75% methane, 20-50% CO2, H2O, nitrogen, oxygen, H2S, ammonia, and other impurities such as siloxanes, mercaptans and other volatile organic compounds. Different assets of biogas compositions from technical papers are aggregated in the data-file, showing the variability by feedstock.
Indeed it is interesting to note that the biogas compositions are not fixed, but vary over time, as the anaerobic digestion progresses in batch reactors, or as different feedstocks are added into continuous digesters (examples charted below). This requires flexibility and advanced planning for biogas upgrading facilities.
It is important to remove the most harmful impurities before combusting biogas, while to make biogas fully fungible with natural gas, and blendable into pipelines, it should be upgraded into biomethane. The Impurities tab of the data-file summarizes each impurity, what it is, why it matters, and how it is removed.
This data-file estimates the costs of upgrading biogas to biomethane. We have a dedicated model for filtering biogas using activated carbon (title charts above), which can remove siloxanes, volatile organics and some H2S.
We have also aggregated the results from stress-testing our other models, including for pressure swing adsorption, amine plants, membrane separations, cryogenic gas separations, gas dehydration, compressors and small-scale pipelines.
Total costs of upgrading biogas into biomethane (and then compressing it to pipeline grade, and building a short pipeline connection) are estimated at $7/mcf, of which $3/mcf is biogas treatment, $3/mcf is further upgrading and $1/mcf is midstream-related.
Capex costs are estimated in the range of $200-1,000/Tpa of biogas inputs depending on the lengths of the pipeline interconnection. A breakdown is given in the data-file, including comparisons with other estimates from other industry bodies and technical papers.
These costs can be worthwhile when they will be covered by fiscal incentives, CO2-conscious buyers, or for improving energy security.
Please download the data-file for further details on our numbers, the costs of upgrading biogas into biomethane, costs of activated carbon biogas filtering or for the varying compositions of biogas. We have also modeled the costs of biogas production and tabulated global biogas production by country as part of our biofuels research.