GWh, Nm³, bcm y MJ: understanding the units of measurement for biomethane

Different indicators used to describe the same form of green energy

Madrid. 13 October 2026. A biomethane plant can produce 1,000 Nm³/h, generate 90 GWh a year, or form part of a market whose capacity is measured in bcm per year. These three figures can describe the same reality from different perspectives: flow rate, energy produced and gas volume.

Understanding the units of measurement for biomethane is essential for comparing plants, interpreting energy targets or determining how much energy a given volume of gas contains.

The key concept is simple: m³ and Nm³ measure volume; Nm³/h measures flow rate; kWh, MWh, GWh and TWh measure energy; MJ and GJ also measure energy; and bcm is used to express large volumes of gas.

In Europe, these units are in constant use. The European Biogas Association (EBA), for example, estimated that by 2026 the continent’s installed biomethane production capacity would stand at 8.2 bcm per year, having exceeded 8 bcm for the first time.

Volume, flow rate and energy: the fundamental difference

Before converting units, you need to know what each figure represents.

Volume answers the question: how much gas do we have? It can be expressed, for example, in cubic metres.

Flow rate answers another question: how much gas flows or is produced per unit of time? Hence units such as Nm³/h.

Energy, for its part, indicates how much energy that gas contains and can be expressed in kWh, MWh, GWh, MJ or GJ.

That is why 1,000 Nm³/h and 100 GWh/year are not directly comparable quantities. The first figure describes a rate of production; the second, the total amount of energy accumulated over the course of a year.

How many households can 1 GWh of biomethane supply?

The European Biogas Association’s (EBA) Energy Translator tool links biomethane capacities to everyday examples such as households supplied, LNG lorries, fertiliser production or emissions avoided. For a biomethane capacity of 1 GWh/year, the tool presented by the EBA provides, amongst other figures, energy equivalent to the annual consumption of 87 European households.

Las capturas facilitadas mueThe screenshots provided also show that the translator associates:stran también que el traductor asocia:

• 1 GWh/year of biomethane → 87 European households per year
• 1 GWh/year → 462 tonnes of CO₂ avoided per year
• 1 bcm/year → 907,140 European households per year
• 1 bcm/year → 4,832,928 tonnes of CO₂ avoided per year

These figures are very useful for communicating impacts, but they are not universal physical equivalents. They depend on the assumptions made by the tool: average household consumption, the technology being replaced, emission factors and other variables. The EBA itself presents its Energy Translator as a tool designed to link units and capacities to examples of impact.

Why is biomethane described in so many different ways?

Because biomethane is simultaneously a physical gas, an industrial flow and an energy source. An engineer designing a plant needs to know how many Nm³/h will flow through a pipeline. An energy operator may need to know the MWh or GWh injected. A government may set its national targets in TWh/year. And an analysis of the European market may refer to bcm/year. No single unit is better than another. Each answers a different question. This variety is particularly relevant in a rapidly expanding European sector. The EBA’s Energy Translator allows users to convert energy units, production capacities and quantities such as kWh, GJ, bcm/year or m³/h, thereby facilitating their interpretation.