In the financial statements of a biopharmaceutical or sterile chemical plant, invoices for electricity, natural gas, and primary raw water treatment are consolidated at the end of the month. The controller’s office calculates the total amount billed by the utility providers, subtracts general building costs, and posts the utility costs to the plant’s shared cost center, allocating them proportionally based on total production volume.
From the finance department’s perspective, the books balance.
However, this apportionment approach hides the stark imbalance in one of the most expensive inputs in process manufacturing: critical clean utilities. Producing Water for Injectables (WFI) via mechanical or thermoelectric distillation, generating pyrogen-free Pure Steam, and performing successive cycles of Clean-in-Place (CIP) and Sterilize-in-Place (SIP) entail exponential thermodynamic costs.
When the plant cannot measure how many liters of WFI and how many kilograms of pure steam were specifically consumed to prepare, clean, and inert the reactor for that particular production order, the unit cost of the batch becomes a fictitious accounting estimate.
The plant operates under a dangerous assumption: that the cost of the batch only begins to accrue when the first high-value raw material is unloaded into the tank. In the reality of aseptic areas, the plant’s most expensive tap has already been running for hours before the reaction even begins.
Purified water is not equivalent to ordinary tap water. Producing one cubic meter of WFI in accordance with the requirements of international pharmacopoeias involves intensive stages of demineralization, double-pass reverse osmosis, ultrafiltration, deoxygenation, and thermocompression evaporation, followed by continuous recirculation through 316L stainless steel loops maintained at over 80 °C to prevent biofilm formation.
Every liter of WFI pumped into a preparation tank carries a heavy load of kilowatt-hours, steam, and continuous analytical monitoring of conductivity and Total Organic Carbon (TOC).
When operational management treats this volume as a fixed infrastructure cost, three serious distortions in decision-making occur:
Many industrial managers argue that CIP skids and WFI generators are already automated and have flow, temperature, and conductivity meters displayed on the utility’s supervisory screens.
However, Level 2 automation (SCADA) is focused on machine control, not business accounting:
To eliminate cost blind spots in sterile areas, the MES (Manufacturing Execution System) layer must serve as the integrator between production events and physical utility meters, structuring governance in accordance with ISA-88 (batch control) and ISA-95 standards.
The solution involves dynamic utility allocation based on the manufacturing context:
In the ISA-88 model, the pre-wash, alkaline wash, acid neutralization, final rinse with WFI, and steam sterilization (SIP) steps are modeled as mandatory preliminary phases of the master recipe. The MES only initiates the ingredient weighing or dosing phase if the preparation phase has been successfully completed. All consumption of supplies and machine time associated with sanitization is recorded under the identifier of that specific order.
Instead of rinsing the reactor for a fixed duration (“rinse for 40 minutes”), the MES directly monitors the conductivity and TOC sensor readings from the skid drain. When the rinse effluent reaches the same purity as the inlet water (indicating that all residues have been removed), the system immediately stops the rinse. This automation eliminates unnecessary WFI consumption and reduces vessel downtime.
The amount of water and energy expended during a product changeover depends on the product that was in the vessel and the product that will be loaded next. The MES manages the compatibility matrix: transitions between similar products trigger simplified CIP recipes; changes between incompatible molecules trigger full heavy sanitization cycles. The plant avoids using the same conservative maximum recipe for all scenarios.
Instead of sending a theoretical estimate of manufacturing costs to the ERP, the MES reports the exact quantity of indirect inputs consumed to the accounting close: cubic meters of WFI, kilograms of pure steam consumed during SIP, hours of sterile compressed air, and the volume of effluent generated for treatment. Product pricing now reflects the physical reality on the production line.
Treating the consumption of clean utilities with the rigor of direct allocation brings tangible benefits to the plant’s finances and operations:
In the pharmaceutical and biotechnology industries, accepting the notion that production costs are limited to the ingredients that go into the bottle is a governance error that silently erodes business profitability. The steam that sterilizes the circuit and the water that rinses the line are raw materials with extremely high added value and must be controlled with the same metrological and accounting rigor applied to active ingredients.
By connecting utility automation to the MES’s execution intelligence, the plant eliminates hidden waste in the piping, dispels the illusion of average energy allocations, and ensures that industrial management understands exactly how much it costs to prepare each vial even before production begins.
Does your plant still treat WFI, pure steam, and CIP cycle consumption as a lump-sum expense allocated at the end of the month?
The PlantSuite MES platform offers advanced execution control with the Batch (ISA-88), Historian, and Production Tracking modules. Integrate CIP skids, flow meters, and process transmitters directly into the active production order, eliminating waste from extended cleanouts and allocating costs with surgical precision in your industrial accounting.
👉 Talk to the experts at PlantSuite and find out how to stop the invisible drain of utilities on your factory floor.