Introduction The overall objective of this project is to develop standardised test methods for the parameters (mainly impurities) to be monitored when injecting biomethane into the natural gas grid and when using it as a vehicle fuel. A further objective is to develop or improve the measurement standards for these parameters, in order to enable SI traceable calibration and measurement results. This project will closely liaise with the biogas producing and upgrading industry, regulators and biomethane testing laboratories to ensure that the developed test methods are robust and efficient and can readily be implemented. The need As European natural gas resources decline, the EU is depending increasingly on imported natural gas. Consequently, diversification of the European natural gas supply has become necessary and this is being implemented as required by the Renewable Energy Directive 2009/28/EC. EC targets also specify that 20 % of EC energy consumption should come from renewable sources by 2020 and that biofuels should provide at least 10 % of transport petrol and diesel consumption by 2020. Under mandate M/475, CEN/PC 408 developed specifications for biomethane (i.e. EN 16723-1 for injection into natural gas grids and prEN 16723-2 for transport fuel). In order to assess conformity with these specifications this project aims to develop new and novel standardised test methods, for example: the content of total silicon and siloxanes, halogenated volatile organic compounds (VOCs), hydrogen chloride (HCl), hydrogen fluoride (HF), ammonia, terpenes, compressor oil and amines in biomethane, as well as the supporting measurement standards. In addition, the project will address the short term stability of measurement standards for these groups of components, as this needs to be improved in particular for siloxanes and halogenated VOCs. Currently, the test methods cited in EN 16723 are neither harmonised nor validated, lack aspects of metrological traceability, and are usually not dedicated to biomethane. Thus they are hampering the energy transition from natural gas to biomethane and are causing the realisation of the EC’s H2020 goals to be too slow. Regulators, grid and refuelling station owners, and testing laboratories urgently require harmonised and validated test methods to enable the transportation of biomethane using existing infrastructure as well as clear financial transactions without disputes. By making these harmonised test methods for biomethane available, this project will enable end users to meet contractual and consumer protection obligations and safety requirements. This project will also enable laboratories to implement these dedicated testing methods and to obtain the necessary laboratory accreditation to underpin their competence in novel measurement services. For legal purposes, a standardised test method is also needed for determining the fraction of biogenic methane in blends of biomethane and natural gas.