biogaspartner – a joint initiative.

Value.Chain.of.Biomethane.
Criteria PSA PWS Genosorb MEA DEA
Adsorption process physical physical chemical chemical
Pre-cleaning necessary? Yes No No Yes Yes
Required pressure (bar) 4 –7 4 –7 4 –7 depressurised depressurised
Methane loss 3–10 % 1–2 % 1–4 % < 0.1 % < 0.1 %
Methane content of the gas product > 96 % > 97 % > 96 % > 99 % > 99 %
Required power consumption [kWh/Nm 3 ] 0.25 < 0.25 0.25–0.33 < 0.15 < 0.15
Required temperature range [°C] No No 55 –80 160 160
Range of controllability as percentages of total load +/– 10–15 % 50–100 % 50–100 % 50–100 % 50–100 %
Processes already underway > 20 > 20 3 3 1
Table: Parameters of different upgrade technologies. Source: Fraunhofer Umsicht (2009).
of the relevant legal provisions and may only deviate within the
range of these quality standards. such standards are realised
using technologies for reconditioning gas. Because a non-negligible
quantity of energy is necessary for gas compression, the
energy balance and the economic feasibility of the compression
and feed-in process must be reviewed on a case-by-case basis.
Accessory.gas./.exchange.gas.
With regard to feeding biomethane into the natural gas grid, it
is necessary to distinguish between exchange gas and accessory
gas. The difference lies in the quality of the gases. an exchange
gas has the same qualitative standards as conventional natural
gas and can be exchanged in the grid as such. accessory gas possesses
a composition that is not equivalent to that of the natural
gas, and can therefore only be mixed into the grid beneath a
certain threshold.
Quality.standards.
regulations distinguish between low-quality natural gas
(“natural Gas L”) and high-quality natural gas (“natural Gas H”).
natural Gas H possesses a higher methane content, and is used
mainly in the GUs federal states and extracted principally in the
north sea.
natural Gas L contains roughly 89 percent flammable gases
(primarily methane, but also small amounts of ethane, propane,
butane, and pentane), while natural Gas H contains about
97 percent flammable gases (the same as those listed for natural
Gas L).
The types of natural gas available in Germany vary with geog-
raphy. similarly, the degree to which biomethane is upgraded
depends on the region of its origin.
4.6.Sales.and.trade.
The transport and sales of the injected biomethane is usually
coordinated by a biogas or natural gas trading company. To
transfer biogas from its production site to its end customer,
36 B I o G a s P a r T n E r – a j o I n T I n I T I a T I v E
these trading companies enter various business and contractual
relationships with different partners. The following overview
gives an idea of the biomethane sales dynamics in Germany.
Biogas Accounting Grid Contract.
In order to transport the injected biomethane via the gas grid,
the trading company (also called “transport client”) is required
to close a biogas accounting grid contract with the accounting
grid operator. The grid operator balances the account of the
biomethane amounts fed-in and out of the grid in an accounting
grid and settles surplus and shortage quantities with the
transport client.
Grid Entry Contract.
In order to be allocated to an accounting grid, the biogas supplier
enters a contract with the Entry Grid operator. In this Grid
Entry Contract, the parties agree on the quality criteria for the
injected gas.
Grid Exit Contract.
The final customer enters into a grid exit contract with the exit
grid operator settling the gas withdrawal at the physical gas
exit point. The costs for the grid transport are the same as in
natural gas transport transactions and are covered by the final
customer together with grid access fees regardless of the feed-in
location.
Biomethane sales and trade in Germany differs from classic
natural gas trade regarding the necessary proof of origins. The
amounts of biomethane fed into the natural gas network must
be documented along the value chain regarding the attributes
required by law (“produced from renewable primary sources,
for example). These attributes mostly derive from the legal and
political conditions set in the renewable Energy sources act
(EEG) and the renewable Energies Heat act (EEWärmeG).
next to transport logistics and accounting matters, the trad-
ing company also coordinates a gas portfolio. The company
buys biogas quantities from various producers and delivers
it to different (end) customers. also, the trading company is