Biogas upgrading to biomethane - The Biogas: Science, Production and Applications - page 367

15.21 Specific biogas upgrading costs for a membrane separation

system based on price indications and warranty values according to [45]
(Copyright: Fraunhofer IWES, 2012).

product gas (CH 4 concentration 97%). Methane recovery rates of 95.0%
and product gas pressures of 7 bar are assumed.
All specific costs stated in this chapter are related to product gas
(H s = upper heating value). In all cases, the specific upgrading costs of
higher calorific raw gases are lower. This is primarily due to increased
energy outputs because overall costs are related to higher energy levels.
However, it can be partly also influenced by increased efficiencies (decreased
energy demand per energy output) because specific energy demands can be
decreased using higher calorific raw gases.
Furthermore, the influence of energy costs will be discussed (all variations
are related to raw gas with 55% methane). As a 'base scenario', electricity
costs of 0.15

/kWh th were assumed. Apart
from the amine scrubber costs, electricity costs were varied by plus and
minus 20% (absolute by 0.03

/kWh el and heat costs of 0.04

€ €

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/kWh el ) compared to the base scenario.
Depending on the upgrading method and plant size, this corresponds to
increased or decreased specific upgrading costs of 0.08-0.13 cent/kWh Hs .
For amine scrubbers, heat costs were varied by plus and minus 25%
(absolute by 0.01

€

/kWh th ) compared to the base scenario. This corresponds
to increased or decreased specific upgrading costs of 0.10 cent/kWh Hs . The
same effects would apply if energy consumptions were increased or
decreased by the above presumed percentage rates. Basically, all results
always have to be regarded together with pressure levels of the product gases
and the framework conditions described above.
Another important parameter for cost-efficient biomethane provision is
the operational availability and nominal load operation. Nominal load
operation of upgrading plants not only depends on high availabilities of the

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