Dossier ENGIE
How to calculate the price per m³ of gas
Have you noticed that your gas supplier bills you in kWh while your meter records consumption in m³? To understand how much one cubic metre (m³) of gas really costs, ENGIE brings you this guide.
Your gas bill may look like an algebra problem. Would you like to clearly understand what makes up your gas price per m³ and how it is calculated from your consumption in kWh? To learn everything about gas pricing, its variations depending on municipalities and suppliers, and the calculations needed to convert your energy volume into consumption levels, follow the guide.
How is the price per m³ of gas calculated from your consumption?
On your gas bill, one detail can be confusing: although your consumption (and therefore your payment) is expressed in kilowatt-hours (kWh), your meter reading is displayed in cubic metres (m³).
How is this possible? This is because the number of kWh contained in one cubic metre of gas is not always the same from one day to another or from one region to another. As a result, the price per m³ of gas can vary. This is why your supplier measures volume in m³ based on your meter, by calculating the difference between two successive readings. It then converts this volume into kWh, the unit that measures the energy produced by burning natural gas.
To calculate the gas price, your supplier applies a conversion factor, also called a thermal coefficient. This is defined by GRDF. It depends on three criteria: atmospheric pressure (linked to the altitude of your home), temperature, and the composition/quality of the gas.
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Gas origin also plays a role
It is also important to know that gas origin affects the conversion factor. For example, gas coming from the Netherlands has a lower calorific value at altitudes below 400 metres: this is called type B gas. Type H gas, on the other hand, has a high calorific value at all altitudes, including above 1,000 metres; it mainly comes from the North Sea or Algeria.
On average, the conversion factor is around 11.2 kWh/m³ for H gas, and around 10.0 kWh/m³ for B gas.
If you want to estimate your gas consumption in kWh yourself, you can do so in two steps.
First, calculate the volume consumed in m³. Simply take a meter reading one month apart and subtract the starting index from the final one.
Then apply the following formula:
Gas consumption in kWh = volume consumed in m³ × conversion factor
You can find the conversion factor applicable to your home on your gas bill. It is a mandatory item on the bill.
You can also find this information on the GRDF website.
What are the components of the gas price?
The price per m³ of natural gas is not fixed over time. It varies according to two main factors: your consumption class (gas for cooking, hot water and/or heating) and the gas tariff applied by your supplier.
What is the gas consumption class?
When subscribing to a natural gas market offer, your supplier asks you to choose a consumption class (or consumption profile). Depending on this, a specific subscription fee is applied. The price per kWh of gas also varies by class. In general, the higher your consumption profile, the more gas you use, the more attractive the kWh price becomes. However, your subscription fee will be higher.
There are four main consumption classes:
The base tariff: for consumers using less than 1,000 kWh of natural gas per year. This is very low consumption, mainly for cooking (gas hob).
The B0 tariff: for consumers using between 1,001 kWh and 6,000 kWh per year for hot water, but using another energy source for heating.
The B1 tariff: for consumers using gas for heating, hot water and cooking, with annual consumption between 6,001 kWh and 30,000 kWh.
The B2I tariff: for consumption between 30,000 and 300,000 kWh per year. This is mainly for apartment blocks and collective buildings.
If your gas consumption changes, you can contact your supplier to change your consumption class.
The cost of gas supply
The gas tariff set by the supplier is also based on the cost of energy supply: gas (and oil) market prices, natural gas procurement, and customer management costs.
Transmission and storage costs
Supplier pricing also depends on the tariff zone in which you live. Depending on the distance between your home and the natural gas storage centre, transport times and costs vary.
This is why the price per kWh of gas is often higher in areas that are harder to access or further away, reflecting higher transmission costs.
In France, there are six different zones. However, your tariff zone does not affect your subscription price.
Government taxes
Gas prices are made up of approximately 51% supply costs, 26% transmission costs, and 23% taxes(1). These proportions may change over time.
On your bill, around one quarter of the gas price per kWh is made up of the following taxes:
The Tariff Contribution for Gas Transmission (CTA): it funds pension rights for employees under the electricity and gas industries scheme. It applies to the fixed part of transmission tariffs.
The Internal Tax on Natural Gas Consumption (TICGN): applied to consumers using gas as a fuel.
VAT (5.5% on your gas subscription and CTA, 20% on consumption and TICGN). It is worth noting that VAT in France is among the lowest in Europe.
Calculating the price per m³ of gas: key takeaways
The price per m³ of gas therefore depends on the value of the conversion factor, which itself varies according to two criteria: gas composition and the altitude of the municipality.
The first depends on the quality of gas supplied from different importing countries, mixed together to form the gas you use daily.
The second directly affects your gas price: the higher the altitude of a municipality, the lower the density of natural gas, and therefore the lower the conversion factor.
The gas price also depends on your consumption class (base, B0, B1, B2I), supply costs, transmission costs to your home (itself linked to the tariff zone), and government taxes.
You can find your local conversion factor on the GRDF website or on your gas bill.
Can I produce natural gas myself?
Yes! With domestic methanisation, it is entirely possible to produce natural gas. However, while self-production can reduce your reliance on the network, it is unlikely to be sufficient if you use gas for heating, for example.
How can I “green” my gas consumption?
If you want to support renewable energy production in France, you can subscribe to the Gaz Vert+ option. You choose the percentage of green gas you want, and ENGIE commits to injecting an equivalent amount of biomethane produced in France into the network.
How can I estimate my gas consumption?
To forecast your gas consumption, ENGIE provides an energy consumption simulator. In just a few clicks, you answer simple questions and ENGIE provides an estimate of your consumption and budget.
