Technical standards for biomethane and natural gas

The legislative decree n. 28 (March 2011) defines the biomethane as a "gas produced from renewable sources with the characteristics and usage conditions corresponding to those of natural gas and suitable for placing in the natural gas grid."

Within three months from the date of publication of the Decree (art. 20) the Italian Authority for Electricity and Gas (AEEG) should have issued specific directives in relation to technical (minimum physical and chemical characteristics) and economic conditions for the injection of biomethane into the natural gas grids.

Until September 2012, unfortunately, the new guidelines have not yet been published.

For this reason, nowadays italian laws do not allow the injection of biomethane into the natural gas grid.

Requirements for gas quality

Requirements for natural gas quality according to italian national standard
Component Unit Value from-to
Wobbe Number MJ/Sm³ 47.31 - 52.33
Gross calorific value MJ/Sm³ 34.95 - 45.28
Relative density (Air=1) 0.5548 - 0.8
Temperature (in the injection gas) °C <50
Water dew point °C <-5
Hydrocarbon dew point °C <= 0
CO2 % <= 3
Oxygen in dry gas grids (O2) % <=0.6
Water mg/m³ No water in liquid form
Sulphur in total mg/Sm³ <=150
Hydrogensulphide (H2S) mg/DSm³ <= 6.6
Mercaptans mg/Sm³ <= 15.5

Grid access restrictions

With Resolution No. 108/06, the Authority for Electricity and Gas has approved the "Codice di Rete per il servizio di distribuzione gas – CRDG”.
The CRDG is an act of fundamental importance for the development of the natural gas market as a contractual tool with which are regulated and deeply clarified the relationship between the companies that manage the natural gas distribution and the sales companies. With the adoption of this instrument, the distribution companies are obliged to offer neutrally and non-discriminatory distribution services to companies and sales to wholesalers.
The main owner of the italian Natural Gas Network, Snam Rete Gas, drafted and transmitted to the Authority for electricity and gas, on 14th November 2002, its “Codice di Rete” (“Network Code”), in compliance with article 19 of the 17th July 2002 Delibera no. 137 and in compliance with article 24, sub-section 5 of Law Decree no. 164 of 23rd May 2000.
On 20th June 2003 Snam Rete Gas transmitted to the Authority the amended document, drafted on the basis of the modifications and supplements that were requested by the Authority.
On 1st July 2003 the Authority for electricity and gas approved the Network Code, with Delibera no. 75/03, prepared by Snam Rete Gas, that therefore complies with article 24, sub-section 5, of the Law Decree 23 of May 2000, no. 164.
More informnation:

Probably biomethane will have to follow the specifications of natural gas before to be injected into the grid. The reference standards for access to the national gas system are contained in Legislative Decree 164/2000, implementing Directive 98/30/EC, which provides that for any reason may be refused access to the existing system in the case of natural gas produced in the national territory and in the territorial sea.