The 6.5-Ton Problem Hiding in 'Disposable' Drug Factories

A single 2,000-liter single-use drug batch can throw away up to 6.5 tons of CO2-equivalent in plastic and packaging. That number is what flipped the industry's long-standing rule that disposables were greener than stainless steel. The flip did not come from new equipment. It came from the grid.

The old case for single-use bioprocessing ran on a simple trade. Cleaning and steam-sterilizing stainless-steel tanks takes a lot of energy, so the cheap move was to grow the drug in a plastic bioreactor, a sealed disposable vessel where cells produce the active ingredient, and toss it when the batch is done. That calculus held for two decades. It is now broken, and a new analysis led by Jan Reiners, a process-engineering specialist at Roche, lays out the mechanism behind the break.

The energy needed to clean and sterilize stainless steel is shrinking fast, because the electricity that powers those steps is going green. Plastics do not get the same relief. The carbon baked into fossil-fuel-based plastic is locked in at the resin plant and never decarbonizes, and a hybrid facility that pairs stainless steel with disposables uses less than half the plastic of a single-use-only plant. As power grids clean up, the cleaning-energy penalty that originally favored disposables shrinks toward a rounding error on some steps, while the embedded carbon in single-use bags, tubing, and packaging stays put. The trade no longer favors disposables on the most energy-heavy steps, including buffer and media prep, where the same cleaning cycle runs over and over.

Reinforcement came this year from Ecoinvent, the Swiss life-cycle inventory database the industry uses to model the carbon footprint of materials and chemicals. Version 3.12, released in late 2025, raised the modeled CO2 impact of fossil-fuel-based plastics by roughly 30%. The plastics were always there. The accounting now sees them. The 6.5-ton figure for a 2,000-liter single-use batch reflects that update, and it covers only the plastic and packaging stream, not the bioreactor's other inputs.

The implication is not that single-use technology is bad. It is that the right answer is a hybrid. Stainless steel for the steps that are energy-heavy and run continuously, single-use where speed and contamination control matter most. Modern "functionally closed" processing means single-use and stainless-steel lines can run side by side in the same ISO-class cleanroom, the air-quality standard drug plants must meet, which used to be a single-use advantage and is now a shared one. Single-use logistics still win on warehouse footprint, on rapid changeovers, and on clinical and small-batch work where a new process is still being tuned.

Roche reports it has reached 100% sustainable electricity across its global operations. AstraZeneca has targeted a 98% reduction in energy-related emissions by 2026, on the way to fully renewable heat and power. Novartis says its energy will be carbon-neutral by 2025. The shared mechanism is "market-based emissions accounting," a way for drug companies to decouple their reported emissions from the carbon intensity of the local grid by signing long-term power purchase agreements and installing on-site solar. The electricity that runs a stainless-steel cleaning cycle is increasingly renewable even where the wall plug is not, and Reiners' analysis assumes that accounting convention.

In regions where the local grid is still coal-heavy and the drug maker has no renewable contract, the old single-use advantage can persist. A plug-in-the-wall stainless-steel line in West Virginia still pays the cleaning-energy penalty in full. The hybrid recommendation is contingent on the grid, or on the company's willingness to fix the grid's color with a long-term contract. The paper does not pretend otherwise.

That is also why a planning department that asks only "is single-use greener?" is asking the wrong question. The right questions are: what is the carbon intensity of the electricity that will actually run this line in five years, what does the company already contract for, and which steps are energy-heavy enough to favor steel. Reiners and his co-authors call the hybrid facility the environmental sweet spot. The reason is structural: steel wins on the cleaning steps, plastic wins on the rapid-changeover steps, and the cleanest answer is a plant that picks the right material for each step rather than committing to one technology for the whole campus.

The team's next move, Reiners tells GEN, is to apply the same framework to fill-finish, the line that fills and finishes vials, and to the cold-chain packaging that wraps every dose. The carbon math on those steps has not yet been re-graded the way upstream bioreactors just were.