Le biogaz s’affirme comme une nouvelle source d’énergie renouvelable, locale et contribuant à la réduction des gaz à effet de serre (GES). Son cycle de production repose sur la méthanisation des boues issues du traitement des eaux usées ou des déchets municipaux, industriels ou agricoles et également des installations de stockage. Il s’agit d’une technique de dégradation de la matière organique dans un milieu contrôlé, dépourvu de lumière et d’oxygène. Ce procédé aboutit notamment à la production d’un mélange gazeux, le biogaz, permettant de produire des énergies renouvelables : de l’électricité et de la chaleur ainsi que du biométhane pouvant être injecté sur le réseau de gaz de ville ou transformé en biocarburant. Un exemple réussi de boucle vertueuse pour valoriser au mieux les ressources ! open_resource magazine a rencontré les ingénieurs de SUEZ qui innovent pour mener à bien la révolution énergétique et faire prospérer la filière du biogaz, notamment en France.
Naissance d’une filière « circulaire »
It is now possible to produce a fuel that does not emit any fine particles, and hardly any nitrogen oxide. How? By recovering the biogas produced by the sludge from wastewater treatment plants. A real blessing in the fight against global warming, which demands local solutions capable of producing green and innovative energies.
The regulation has changed radically in the last few years, opening a whole new chapter for energy. In 2011, French legislation was passed setting the first tariffs for the purchase of biomethane that is injected into the natural gas grid. Four years later, in 2015, the law on the energy transition was adopted. It also saw the announcement of a target of 10% of gas consumption from renewable sources by 2030 (1). The French Council of Ministers confirmed the announcement in April 2016. “Biogas contributes to the development of renewables, to the reduction of greenhouse gas emissions and to the development of the circular economy, by reusing waste that is produced locally”. In the same year, 215 gigawatts/hour of naturally-sourced methane were produced in France, the equivalent of the consumption of almost 18,000 households.
Today, around 20 sites inject biomethane into the mains supply, and more than 200 projects are in progress. This trend is due mainly to the obligation imposed on major biowaste producers (2) (food waste or biodegradable waste) to have their waste sorted and collected, or to recover it themselves. Therefore, one can understand that a company like PRODEVAL, a market leader for the production of biogas in France that SUEZ supports through a financial investment (3), is growing rapidly. Its VALOPUR® technology uses high-performance membranes to recover the biogas produced by the methanation of organic waste and purification station sludge. This innovation is definitely part of the French and European strategy on renewable energies. As Pierre Coursan, SUEZ’s Biomethane Global market manager for France, states today, we are in the middle of an energy revolution.
And in the future? By 2030, sludge, waste and effluents from livestock farming in France could represent a global source for methanation generating 56 TW/h of primary energy per year. Or… 560 times more than today! In 2020, the installed capacity will reach 625 MW of electricity, or more than twice the initial objective.
À Strasbourg, le circuit court est roi
Local authorities were quick to show an interest in biogas, because this new circular production cycle offers the means of developing locally-sourced renewable energy. As the Energy Manager in SUEZ’s Environmental Engineering Division, Gilles Bideux, explains, the benefits of biogas for local authorities are obvious: “A fossil product, that is often imported and emits greenhouse gases, is replaced by a neutral product in the network that is produced and consumed locally“.
This is the reason why the Biovalsan project prompted the City of Strasbourg, through the “Réseau GDS SEM” (4) that it controls, to work with SUEZ on the “Biogénère” joint venture. This pilot project was developed with the financial support of the European Commission’s LIFE programme (5) for the conservation of the environment. The goal for Strasbourg is to become the first city in France to inject biomethane from a wastewater treatment plant into the urban natural gas network. Fuel made from biomethane addresses the issue of clean and sustainable mobility. It cuts greenhouse gas emissions by 90% in comparison with fossil fuels and does not emit any fine particles that are harmful to health.
Advanced studies were necessary before biomethane could be injected into the natural gas network. A working group, comprising all the energy players involved (Ademe (6), the responsible authorities, the local gas network, the operators, etc.), made detailed studies of the pilot project’s technical, economic and health aspects. “We studied the health hazards in order to establish beyond doubt that biomethane can be injected into the networks in complete safety.We also completed design studies, drew up a business plan and, after reviewing and auditing the available technologies, we opted for membrane separation technology, which is used to produce industrial air. In June 2014, this project contributed to the birth of a regulatory framework favorable to the launch of the sector of biomethane from wastewater treatment plants, thanks to the constructive dialogue between the project owners, the Ministry of the Environment, the Energy and Climate Directorate and the Energy Regulation Commission” explains Frédéric Pierre, the HQS2E (7) and Development Manager at SUEZ Water France, and the Biovalsan project manager.
The collaboration with SUEZ is a reflection of the city’s ambitions. “When we took over the control of the operations and development contract of the Strasbourg wastewater treatment plant, it did not recover many of its internal energy resources, and was highly dependent on fossil energy. So we built a new target energy model, with the goal of becoming independent from fossil energy and recovering the internal energy resources, in order to export the biomethane and inject it into the urban gas network“, explains Frédéric Pierre.
In line with the city of Strasbourg’s objectives, the biomethane activity is being developed as part of a short circuit. 100% of the green gas produced in the wastewater treatment plant is intended to be consumed by local users, with priority going to sustainable urban development projects (large tertiary buildings, eco-districts) and clean mobility. Ultimately, some of the biomethane will be used to fuel vehicles running on natural gas.
While the potential of the sludge from the wastewater treatment plants may not be as great as that of agricultural waste, it does have a number of other advantages, such as reduced noise and olfactory pollution and the use of existing infrastructures, in the shape of the wastewater collection network, which limits investment. Annual production in Strasbourg converts wastewater into a volume of energy equivalent to the annual consumption of 5,000 low-consumption buildings.
Nouveaux métiers ou chaîne de valeur « augmentée » ?
In a recent publication(8), Ademe highlighted the need to give greater consideration to the local acceptability of agricultural waste projects and to concentrate on technical innovations that will further optimise the recovery of biogas as energy. Biovalsan contributes to this trend by working on new methods to dry sludge, that do away with the internal consumption of biogas, to recover energy from the sludge incineration fumes to heat the methanation units, or to take and analyse samples in situ.
But recovery does not only solve technical problems. It also aims to provide global solutions that support operators throughout their biogas production projects. As Jean-Baptise Decultot, Development Director of SUEZ Organique emphasises: “Methanation is the continuation of SUEZ’s historical activities: site qualification, work on real estate, access to deposits, flow and supply management and the recovery of digestates from the deterioration of organic matter. We are already familiar with these activities related to composting and the spreading of sludge and agricultural waste. Today, these key skills ‘enhance’ other new skills in energy production, and the operation of methanation units in particular”. In other words, historically speaking, treatment is SUEZ’s main activity, and the recovery of biogas is “simply” its continuation. “This also corresponds to a change in the nature of waste or wastewater treatment centres“, continues Pierre Coursan, “which now interact with their local surroundings and produce energy that must be recovered and used by the community“.
Moreover, SUEZ plans to inaugurate new centres, like the one in Faulquemont, in Moselle, France. Each year, the centre will produce 4,000 MWh of green heat, and as much green electricity, from 35,000 tonnes of organic waste from the industry and food, in addition to its more traditional role of recovering waste in the form of fertilisers and compost. But SUEZ can also offer its know-how in recovery to existing methane producers, for example, by creating joint ventures, such as Méta Bio Énergies, in the Pays de la Loire region in France, or by collaborating with players whose core business is the recovery of biogas. This is the case of Waga Energy, a start-up that joined forces with SUEZ to create the Wagabox technology, which produces biomethane from the biogas produced by non-hazardous waste storage facilities, requiring a specific treatment. Today, only 60% of the biogas produced by this type of facility in France is recovered into electricity or heat. This technology allows for improved efficiency. SUEZ has already deployed it on one of its sites and has plans to deploy it on two more. If it works, France’s production of biomethane could rise by 20%.
This growing network in France is supplemented by the group’s international ambitions, with 170 methanation units worldwide already: self-supply with biogas of the largest wastewater treatment plant in Jordan, maximising the energy potential of a brewery in the UK through methanation, or extending the largest composting site in North America, in Edmonton, to produce green energy from waste.
Biogas engineers certainly have a bright future!
(1) The law on the energy transition for green growth, promulgated in 2015.
(2) Since January 2012, producers of waste containing more than 50% biowaste have been obliged to sort at source and to recover organically. Since 2016, companies producing at least 10 tonnes per year of biowaste have been considered as major producers.
(3) Since September 2016, SUEZ Ventures is supporting the development of PRODEVAL on the biogas recovery market by acquiring a 22% minority share.
(4) Mixed economy company. It is the local operator of the city of Strasbourg’s natural distribution gas network.
(5) The EU’s financial instrument supporting environmental and nature conservation projects throughout the E.U.
(6) The French State Environment and Energy Management Agency.
(7) Health, Quality, Safety, Environment and Energy.
(8) Avis méthanisation, November 2016.
This article was published in the fourth issue of open_resource magazine: “The circular economy era"