SUBLIME Energy (Energie): Biogas Straight from the Source

Biogas is a firmly European stronghold, which until now has had its strongholds in Germany and Italy. The case study we are presenting here projects Sublime’s technology into the Hexagon — with some distinctive features.

SUBLIME Energie has inaugurated in Brittany, France, its demonstrator “Charlie.” Here the scale-up moves toward bio-LNG, one of the great challenges in optimizing energy density as an alternative to electrification in heavy-duty applications — most notably long-haul freight transport (ask truck manufacturers in Italy and Sweden…).

On-Farm Anaerobic Digestion Speaks French

Decentralized energy represents one of the defining challenges for the entire productive infrastructure. How to break free from grid shocks in the face of potential overload driven by electrification, produce alternative fuels to navigate the energy transition, stem the hemorrhage of fossil fuels caused by geopolitical tensions, and resolve the endemic bottleneck of biogas production tied to the distribution of biofuels.

SUBLIME Energie’s answer lies in a plant capable of liquefying biogas directly on the farm. For the first time, on-farm anaerobic digestion can produce a renewable fuel without relying on gas grid infrastructure. By densifying and enabling the transport of biogas produced on-site — using a model inspired by the traditional milk collection system — the startup is deploying a decentralized industrial model. In this system, biomethane is converted into bioLNG for heavy-duty mobility, while bioCO₂, a co-product of biogas, replaces fossil CO₂ across a range of agricultural and industrial applications.

With this demonstrator, SUBLIME Energie is scaling up to unlock the full value of a fragmented agricultural resource, turning it into renewable energy and biogenic CO₂.

Today, a significant share of farms remains excluded from biomethane injection. Limited production volumes, distance from gas grids, and high capital expenditure barriers, continue to hinder the sector’s development.

The “milk run” of SUBLIME Energie

SUBLIME Energie introduces a paradigm shift inspired by a simple and proven model: “the hub and spoke “milk run”. Biogas produced on farms is liquefied, then collected locally and transported to centralized hubs for purification and commercialization.

This approach enables smaller or remote farms to participate in renewable fuel production, while bypassing infrastructure constraints tied to gas networks. It also offers a transition pathway for existing cogeneration-based anaerobic digestion units nearing the end of their contracts, extending asset lifespan and improving profitability.

Energy Density

At the core of the solution is a patented process that liquefies biogas directly on the farm, increasing its energy density and enabling off-grid transport. The liquefied biogas is then transported to centralized facilities, where cryogenic distillation separates and upgrades it into bioLNG and liquid bioCO₂. The “Charlie” demonstrator represents the final R&D milestone, integrating all technological building blocks on a single site under real operating conditions.

Installed at the Gazéa farm—one of Brittany’s pioneers in anaerobic digestion—Charlie processes biogas produced on-site, with an annual capacity of approximately 180 tons of bioLNG and 330 tons of liquid bioCO₂. Initial production will begin this year following commissioning and testing phases.

« With Charlie, we demonstrate that it is possible to overcome the historical limitations of anaerobic digestion. By liquefying biogas directly on the farm, we enable an off-grid model capable of unlocking large-scale value from a fragmented agricultural resource », said Bruno Adhémar, Founder and CEO of SUBLIME Energie.

Key Points of the SUBLIME ENERGIE Formula

Beyond technological performance, the project contributes to a broader transformation of energy systems:

• Upstream, anaerobic digestion reduces greenhouse gas emissions from livestock waste and partially replaces the use of fossil-based fertilisers.
• Downstream, bioLNG provides a low-carbon alternative to diesel for heavy transport, reducing GHG emissions by up to 85%
• The solution is also relevant for agricultural and maritime applications, where electrification remains challenging
• bioCO₂ valorization replaces fossil CO₂ in sectors such as agriculture and the food industry.

A significant share of biomethane potential remains untapped due to lack of access to gas networks. This resource, estimated at 26 TWh by 2050 in France, represents a strategic opportunity. SUBLIME Energie aims to capture part of this potential by producing renewable gases locally.

The model is based on purchasing raw biogas from farmers, providing them with a stable additional revenue stream without requiring upfront investment in upgrading infrastructure. Farmers are also welcome to participate in project ownership if they choose.

“There is no future for agriculture in Brittany without livestock farming. Yet the future of livestock farming depends on the democratization of biogas production and the support of this production. SUBLIME Energie’s model is a concrete solution to help livestock farms adapt,” said Alain Guillaume, farmer, founder of Gazéa and of the French Association of Methanizing Farmers.

An Industrial Roadmap Already Underway

With “Charlie,” SUBLIME Energie completes its final technological validation phase and enters industrial deployment. The company is already preparing its next project, “Delta,” which will connect around ten farms to a shared processing hub in Côtes-d’Armor. This first commercial-scale unit is expected to be commissioned by 2028. Beyond that, SUBLIME Energie aims for rapid deployment across France and Europe, with the ambition to structure a new decentralized renewable gas industry.