Germany

Technical standards for biomethane and natural gas

Technical standards for biomethane and natural gas

The Ordinance on Gas Network Access (Gasnetzzugangsverordnung / GasNZV) lays down the basic framework for the overall process on access to the natural gas grid. Biomethane is provided with a priority access to the natural gas grid (§33). The ordinance governs procedural regulation related to biomethane injection in gas grid. The ordinance refers to Deutschen Vereins des Gas- und Wasserfaches (DVGW) worksheets for gas quality specifications for injection and gas transport in public grid. Specification for accounting and billing procedure at exit conditions are also mentioned.

An important aspect of the GasNZV ordinance is the description of cost sharing responsibilities between biomethane connection applicant and grid operator. The cost burden is clearly specified based on length of connection.

Requirements for gas quality

DVGW has published worksheets to specifiy the quality of gases in public grid. 

Biomethane producer who is requesting grid connection has only to confirm to DVGW G 260 and G 262 worksheets specifications. DVGW G 260 (Gas quality) refers to the composition of gas when it is transported in the public gas grid. Biomethane has to confirm on the existing conditions of the regional gas family in the grid. 

DVGW G 262 (use of gas from renewable resource in public gas supply): This worksheet specifies the biomethane producer for final conditions to which the gas has to be upgraded.

Injection of biomethane is either possible as substitute of natural gas or additional gas (G262). Substituting gas has to fully comply with G260. Gas of lower heating value than the of the base gas in the injected grid is allowed to enter as additional gas presumed the resulting gas mix complies with the requirements of G260 and G262 and homogenious mixing is ensured. 

An augmentation with LPG or propane and butane in order to adjust biomethane to become on-spec  is possible. Augmentation of propane is less critical than butane. Adjusting on the gross calorific value of 39.96 MJ/m³augmentation of  propane and butane is possible for an unlimited period. When adjusting to a higher GCV e.g. 43.56 MJ/m³ augmentation is limited on the usage of propane (DIN 51622) and in exceptional circumstances.

DVGW 280 - 1 and DVGW 280 – 2 : Gas odorisation is obligated throughout the distribution grid. These worksheets refer to gas odorisation as well as adjustment of odorisation of gases in the public supply.

DVGW 685 lays down the responsibility of network owner for gas accounting at the exit conditions. This worksheet describes the guidelines for determining volume of billing and calculation of gross calorific value.

Also referring to GasNZV the heating value is first checked at the moment of injection (plant operator) into the gas grid and second when gas is discharged.Monitoring of gas injection regarding quantity and costs is supervised by the Federal Network Agency for Electricity, Gas, Telecommunications, Post and Railway (Bundesnetzagentur) once a year.   

Grid access restrictions

Landfill gas is restricted from entering the public gas grid (DVGW G262) due to the risk of forming dioxine and furane during combustion process.

The feeding of biomethane cannot be denied by the grid operator under premise of capacity shortage and is responsible to ensure and optimize the feed-in capacity (§41d).

Barriers

The amended legal framework is very much is favour for the biomethane plant operator and the grid connection process has been facilitated during the recent years. However, there are still issues for discussion such as:

  • Oxygen content when feeding high pressure grids (e.g. close to underground gas storages).
  • Time periods for implementation of the grid connection take a large proportion of the entire project implementation period, even grid connection process is subject to a fixed time frame described in the GasNZV (“realization roadmap”). A delay of the comissioning date is subject to penalty payment for the gas grid operator.
  • The network operator has to ensure 96% availabilty of the connection which is suspected to increase costs for grid connection, e.g. caused by increased redundancy.