Tribune de Jean-Marc Leroy

What is biogas?

Biogas is a product resulting from the methanization of fermentable organic waste such as agricultural or industrial effluents, household waste, sewage sludge. It is a renewable gas as it comes from waste that would not be valued otherwise. Thus, it integrates the logic of circular economy.

What are the environmental properties of biogas?

Biogas has undeniable environmental benefits as it enables to face three essential stakes for the future of humanity.

First of all, this technology aims at the local development of a low-carbon energy, the biogas, through a virtuous use of the carbon cycle.

Moreover, it is a way to deal with one of the major stake for the future: the waste management issue. Indeed, the 9% increase of the world population by 2030 will cause a 70% rise of waste generation.

Finally, biogas supports the development of a sustainable agriculture by allowing farmers to produce organic fertilizers and thus to avoid the agricultural spreading polluting both lands and groundwaters with nitrogen. Knowing that the production of a ton of artificial fertilizers generates the emission of 7 tons of CO2, biogas offers an ecological solution of agricultural autonomy.

Is there a privileged use of this technology?

The characteristic of all energy is that: the less transformed it is, the more efficient it is.

The best way to use gas is through injections into the network. Injections of biogas, previously purified (and thus called biomethane), into the gas networks transform them into “social networks” as everybody cannot produce at the same time.

The other interesting use of biogas is mobility as there is a strong demand from industrial customers for green mobility.

Concerning farmers remote from gas networks, cogeneration solutions enable farmers to produce at the same time fertilizers, heat, their own electricity and to sell the surplus to the power grid.

What are the societal benefits of biogas?

Methanization should also be seen as a support for maintaining employment in rural areas. Indeed, it represents an additional income – not a replacement one – for farmers. The French Environment & Energy Management Agency estimates this income at 15 000 euros in average in France which is substantial for producers.

To develop biogas, we have to build trust in order to ensure both public and private fundings (involving farmers, banks and the industry) and to guarantee the quality of the sector. This structuring work is particularly deployed in the Netherlands and has to be also replicated in France and around the world.

What about the topic of land use to produce energy and not food?

Firstly, the questionings around the land use for energy production are not relevant concerning the use of agricultural waste in the biogas production.

Moreover, ENGIE believes there is an important potential within the food industry (about a fifth of the agricultural potential) that we should develop respecting strong and clear regulations. The objective is to help developing a sustainable agriculture: the soil quality is an essential question, as is the quality of the fertilizers used.

ENGIE do not base its business models on crops dedicated to the energy production. We believe that the use of intermediate crops is one of the key topic. These crops consist in seeding the fields between two harvests in order to avoid soil nitrification. This process enables the farmers to produce the necessary energy for their future crops while improving soils quality.

Should we develop biogas even though wind and solar power are more mature and therefore less expensive?

I am convinced that developing biogas as planned in certain countries will create a convergence between the price of biomethane and the price of natural gas with a carbon tax by 2030. Indeed, our sector is still emerging and the potential for cost reduction is important.

Besides, the various energies do not deliver the same service and are in total complementarity with each other. The characteristics of gas can thus complement the other energies: it is easily storable and inexpensive to transport.

ENGIE advocates a global vision of energy development by focusing simultaneously on the electrical, the heat and the gas networks to benefit from the technical advantages of each energy. This flexibility and this global vision of the system are essential today: we should not implement a gas advocacy, neither an electricity advocacy but rather be able to go beyond this type of silo thinking to promote a balanced energy mix taking into account the stakes specific to each country.

Should we learn from the German example ? What can we learn from it? What are the main pitfalls to the development of biogas in France?

The German case reaches its limits with the dedicated crops. In some countries the essential stake is above all feeding the population. The issue of access to energy remains a fundamental topic but is more secondary compared to this essential stake.

As long as the farms are not enough to feed the population, food safety must remain the priority. The benefit of biomethane is to deal with both issue in an effective way.

How is the Group working on biogas ?

Many of our structures have mobilized around this topic and have already developed a differentiating expertise.

The work of developing this energy for the future must be done in accordance with the will of the farmers who obviously do not want to be deprived from managing their production and want to ensure the quality of their soils.

The business model defended by ENGIE therefore consists in positioning itself as a partner for farmers, a facilitator, who offers its expertises to develop a green gas and a sustainable agriculture.


Interview conducted by Anne Chassagnette, ENGIE's Environmental and Societal Responsibility Director.

Find out more