Three Practical Boundaries of the ISO 50001 Energy Management System for Printing Plants: Energy Review / Energy Performance Indicators / Change Management—Which Three Accounts Should a Printing Plant Calculate First When a Customer Requests Energy Consumption Data?
💡 💡 At a Glance
ISO 50001:2018, equivalently adopted in China as GB/T 23331-2020, establishes an energy management system whose practical outputs are usable figures rather than merely a certificate. First, the energy review is not an annual spreadsheet: it must estimate future energy use and consumption, document current use and consumption, and identify the principal variables affecting energy performance. It must also be updated when facilities, equipment, systems, or processes undergo significant changes, such as changes in paper stock, surface treatment, machinery, or shift patterns. A practical approach combines a comprehensive annual review with triggered focused reviews covering affected processes, and relies on data rather than impressions. Second, EnPIs and the EnB form a pair: the EnB is the ruler, and the EnPI is the measurement to be observed. If relevant variables materially affect energy performance, both must be normalized. Printing plants should normalize output, product mix, seasonality, press start-ups, and color changes so that year-over-year comparisons reflect efficiency rather than order mix. Third, change management is one of the most practical refinements in the 2018 edition. It requires review and action for major changes to facilities, equipment, systems, or processes; significant changes in energy supply or use; changes in legal requirements or standards; organizational or ownership changes; and deterioration in energy performance. Before responding to customer data requests, a printing plant should calculate three accounts: energy consumption per unit of product, the payback period for equipment upgrades, and post-change performance tracking. Potential upgrades with relatively certain returns include compressed-air systems, drying processes, and the base loads from air conditioning and lighting.
In October 2026, a brand customer that sells outdoor products sent us a questionnaire titled “Supplier Sustainability Data Collection Form.”
One field asked for energy consumption per unit of product (kWh/unit of product).
Sales forwarded the form to us and said: “The customer wants this figure.”
We asked: “What is the denominator? Per sheet, per square meter, or per ton?”
Sales replied: “The form simply says ‘per unit of product.’”
We responded: “Then we can’t provide it. Last month, this factory produced a batch of 400,000 annual gift boxes. This month, we produced a batch of 3,000 reorder boxes. Dividing the kWh for these two months by their respective output volumes can produce figures that differ severalfold. This is not a reluctance on our part to provide data; rather, the figure would be meaningless to the customer.”
The customer asked: “Can’t you at least give us an approximate figure?”
We replied: “An approximate figure is worse than no figure. We once prepared an estimate, and the customer used it to calculate the carbon footprint of their products. The following year, they checked it against an audit report and found that our denominator did not match their assumption. The entire data set was invalidated and had to be redone.”
Behind this incident lies a management-system issue. ISO 50001—the energy management system standard equivalently adopted in China as GB/T 23331-2020—specifically addresses how to turn energy consumption into a comparable, verifiable, and continuously improved figure. This article examines three practical boundaries and identifies the three accounts a printing plant should calculate first when it receives this type of inquiry.
First Boundary: An Energy Review Is Not a Spreadsheet Completed Once a Year
The energy review is the engine of the entire ISO 50001 system. The standard follows this logic: energy review → establish energy performance indicators (EnPIs), an energy baseline (EnB), and objectives → implement improvements → monitor and measure → conduct another review.
The review must produce three outputs: estimates of future energy use and consumption, data on current energy use and consumption, and the principal variables affecting energy performance. Comparing the first two outputs reveals where improvement efforts should be directed.
What truly turns the review into a management system rather than an annual exercise is the standard’s requirements for review frequency and triggering conditions: the energy review process must be periodically updated at established intervals to address any significant changes occurring within facilities, equipment, systems, or processes.
For printing plants, “significant changes” are very concrete and occur several times a year:
A customer changes paper stock, altering its grammage and coating and therefore changing the printing press’s drying energy consumption. A customer replaces lamination with spot UV coating, changing the UV lamp power and the curing section’s machine occupancy. An old machine is replaced with a new one, producing a completely different energy-consumption curve. Operations increase from two shifts to three, changing the base load for air conditioning and lighting.
The customer asked: “How many times a year do you conduct reviews?”
If a plant says “once,” that answer is difficult to defend during an audit because the standard requires the system to respond to significant changes. If the response is too casual, by contrast, it suggests that the system is not actually operating.
Our plant divides the review into two levels: a comprehensive annual review covering every process and all energy carriers, and triggered focused reviews conducted whenever a significant change occurs. The latter covers only the affected processes while maintaining evidence of the update. This preserves the system’s operating rhythm without pretending that nothing changes during the rest of the year.
One point also deserves special attention: energy reviews must rely on data, not impressions.A printing plant owner’s intuition about which machine consumes the most electricity is often wrong. Many people assume that printing presses are the largest energy users, but in many plants, air conditioning and compressed-air systems consume more. If the review is based on impressions, the resulting EnPIs will also be wrong.
Second Boundary: EnPIs and the EnB Are a Pair—Without a Normalized Baseline, Every Comparison Loses Its Meaning
An energy performance indicator (EnPI) is an indicator used to measure energy performance. An energy baseline (EnB) is the organization’s energy-performance level over a specified period, usually expressed as “energy consumption per unit of product or service produced.”
The relationship can be understood this way: the EnB is the ruler, and the EnPI is the graduation on the ruler you need to observe.With only an EnPI and no EnB, you cannot tell whether the current result is good or bad. With only an EnB and no EnPI, you do not know what to measure.
The standard clearly states the critical step: information obtained through the energy review may be used to establish the EnB. If the data show that relevant variables have a significant impact on energy performance, the EnPI values and EnB should be normalized.
For printing plants, normalization is critical. Returning to the opening example: if a customer requests “energy consumption per unit of product,” the printing plant must first define clearly what constitutes a “unit” and normalize away the variables with the greatest influence. Printing plants commonly face three variables: output volume, which is itself the denominator; product mix, because annual gift boxes and small reorder boxes impose very different process loads; and seasonality, including summer air conditioning and winter heating.
There is also a printing-plant-specific variable that many facilities overlook: the number of press start-ups and color changes.Producing 10,000 sheets across 10 SKUs in 10 start-ups consumes far more energy than producing 10,000 sheets of one SKU in a single run. Each start-up requires inking, preheating, cleaning, and setup, during which the machine consumes electricity without producing output.
The customer asked: “How do you calculate the figure in a standard way?”
We replied: “We report the figure adjusted to a standard product mix. We convert the current period’s actual energy consumption for the difference between the current product mix and the standard product mix, then divide it by monthly output under the standard mix. This allows the customer to compare our figures across two years and see a change in efficiency rather than a change in order mix.”
The customer said: “But doesn’t that make the figure inaccurate for our use?”
We replied: “Quite the opposite. Customers want a trend and an intensity indicator for their own product lines, not the billing figure for one particular month of ours. A normalized curve lets them compare our current performance with last year and with peers. That is the data that is genuinely useful.”
Third Boundary: Change Management Is One of the Most Practical Refinements in the 2018 Edition
Compared with the 2011 edition, the 2018 standard made substantial changes to existing energy management systems certified to ISO 50001:2011. For many organizations, revising their old system in preparation for recertification amounted to rewriting it from scratch. One of the most substantive changes is the emphasis on change management.
The standard requires organizations to review the impact on energy performance and take appropriate measures when any of the following occurs: significant changes to facilities, equipment, systems, or processes; significant changes to energy supply or energy use; changes in legal requirements or standards; changes in organizational structure or ownership; and deterioration in energy performance.
The requirement concerning deterioration in energy performance is underestimated. It means that management is necessary even when no physical change has occurred. If installing more energy-efficient lighting results in an increase in total energy consumption, the plant must conduct a review to determine whether a problem has arisen elsewhere.
The most typical failure of change management in a printing plant looks like this: The owner installs a new printing press that saves 15% energy, but no one records the energy baseline before and after the change. Three months later, when a customer requests data, the press’s savings are obscured by production growth, and no one can determine whether the machine actually saved energy.
The customer asked: “What records should be maintained for change management?”
We replied: “Three items: energy-consumption data before and after the change, an assessment of the change’s impact on the EnPIs, and the revised EnB. It sounds burdensome, but in practice it means adding two lines to each piece of equipment’s operating record.”
Another related issue is supplier and outsourcing controls. Once a printing plant outsources certain processes, the statistical boundary of its EnPIs changes. The energy consumed by the outsourced process is not included in the plant’s accounts, even though it forms part of the product’s total energy consumption. ISO 50001 requires organizations to control energy use, including outsourced processes. At minimum, the plant should agree with the service provider to either provide energy-consumption data for each batch or commit to a specific energy-consumption figure per unit of product in the contract.
Which Three Accounts Should a Printing Plant Calculate First When a Customer Requests Energy Data?
When customers ask for energy-consumption data, many printing plants’ first response is: “We do not have ISO 50001, so we cannot provide it.” This reaction unnecessarily complicates the issue. ISO 50001 is valuable, but when customers request data, they need figures, not a certificate.
The first account: How to break down energy consumption per unit of product.First, lock down the denominator—per sheet, per square meter, per ton of adhesive, or per finished box. Then normalize the current-period data for product mix and seasonality. Once this account has been calculated, the customer’s first question can be answered.
The second account: How to calculate the investment payback period for equipment upgrades.After receiving your energy figures, the customer will inevitably ask how you intend to reduce consumption. The plant must be able to identify which process to upgrade, how much to invest, and how long the investment will take to pay back. This calculation usually points to three areas: compressed-air systems, including variable-speed drives and waste-heat recovery; drying energy, including replacing hot-air drying with UV curing and managing UV-lamp replacement cycles; and the base loads from air conditioning and lighting. These three areas generally offer the printing plant the most certain returns.
The third account: How to track performance after changes.After a new machine, process, or shift is introduced, have the EnPIs changed? If so, have they improved or deteriorated? This account can be maintained without a formal management system, but it must be recorded in operating logs. Otherwise, no one will be able to explain the results six months later.
Once these three accounts have been calculated, an ISO 50001 system follows naturally, because the standard requires precisely these actions to be institutionalized, documented, and reviewed. Conversely, building an empty system first and adding the data later produces nothing more than a hollow shell.
A Message for Customers
Regarding energy-consumption data, the most important thing we would like to tell customers is: “Please first tell us what you intend to use the figure for.”
The customer replied: “To calculate the carbon footprint of our products.”
We said: “Then we need to understand your accounting boundary and denominator and align them with ours. Is your figure expressed per ton of product, per square meter of material, or per packaging unit? If your denominator differs from ours, the two figures cannot be combined.”
The customer asked: “Can’t you simply send us the figures?”
We replied: “Yes. But please allow us to send you the calculation basis along with the figures. That single line is more useful than providing three additional months of data, because you will ask us again next year.”
Further Reading
- Three Practical Accounts for Calculating “Energy Consumption per Unit” in Printing—Differences in electricity consumption per unit among offset printing, digital printing, and solvent-ink recovery
- Three Changes in Environmental Electricity Tariffs for Packaging Printing Plants in 2026—When energy-consumption data need to be converted into monetary values
- Three Practical Energy-Saving Accounts for Compressed-Air Systems in Printing Plants—The area most likely to deliver a certain return
- Three Practical Boundaries for Creating a “Green Factory” in Printing Plants—Another set of demanding indicators adjacent to the energy-management system
FAQ
Can a printing plant provide energy-consumption data to customers without ISO 50001 certification?
Yes. Customers need data, not a certificate. The value of ISO 50001 is that it makes the data credible, comparable, and traceable. If you intend to provide data only once and do not expect similar requests in the future, implementing a full management system may be excessive. However, three things are essential. First, clearly document the calculation basis, including the denominator, normalization method, and reporting period; otherwise, the customer may misuse the data. Second, derive the data from energy bills and equipment records rather than estimates. Third, be able to provide subsequent figures using the same calculation basis; otherwise, the initial data may become a burden. Most customer sustainability questionnaires are intended to be completed continuously rather than only once.
How should the denominator for “energy consumption per unit of product” be defined?
It depends on the customer’s product format. Four common denominators are available. Finished product count is usually what customers want because it directly corresponds to their output. Paper input area or weight is easiest for printing plants to calculate internally and allows energy consumption across different processes to be attributed to a common material basis. Production value aligns with the customer’s financial records but is affected by price fluctuations. Machine hours reflect equipment efficiency but do not reflect output. We usually retain two bases: finished product count and paper input for external reporting, while using machine hours internally. After selecting the basis, calculate the historical data for the past two years using each denominator and identify the one that produces the most stable trend. The most stable curve is generally the best basis for year-over-year comparisons.
Why must the energy baseline be normalized, and what problems arise without normalization?
Without normalization, changes in the data reflect shifts in order mix rather than changes in efficiency. For example, a batch of 400,000 annual gift boxes naturally has high energy consumption per unit because of its large surface area and heavy ink coverage. A subsequent batch of 3,000 small reorder boxes naturally has low energy consumption per unit. Comparing the two directly could lead to the conclusion that efficiency has deteriorated when nothing has actually changed. Normalization converts current-period data to standard conditions by adjusting for product mix, seasonality, press start-ups, and other variables. The standard explicitly requires EnPI values and the EnB to be normalized when data show that relevant variables have a significant impact on energy performance. Printing-plant-specific variables include press start-ups and color changes, because each start-up involves inking, preheating, cleaning, and setup, during which electricity is consumed without corresponding output.
How should energy data be handled after new equipment is installed so that it remains accurate and useful?
Change management requires the impact on energy performance to be reviewed whenever significant changes occur to facilities, equipment, systems, or processes. At a minimum, three actions should be taken: obtain energy-consumption data over complete cycles before and after the change for comparison, rather than comparing partial periods; assess the change’s impact on the EnPIs and update the EnB; and record the change in the equipment log and review records. Change management also covers significant changes to energy supply or use, changes in legal requirements or standards, changes in organizational structure or ownership, and deterioration in energy performance. If installing more energy-efficient equipment coincides with an increase in total consumption, a review should be conducted to determine whether another problem exists.
How should a printing plant calculate customer energy data after outsourcing a process without misleading the customer?
This is one of the easiest issues to handle ambiguously. Energy consumed by an outsourced process is not included in the printing plant’s accounts, but it forms part of the customer product’s total energy consumption. ISO 50001 requires control of energy use, including outsourced processes. Three approaches are possible. The most rigorous approach is to include a committed energy-consumption figure per unit of product in the outsourcing contract and require the provider to submit data; this is appropriate when a large share of production is outsourced. A middle approach is to separate the outsourced process price into material, processing, and energy components and use the energy component for normalized estimates. The least rigorous approach is to ignore outsourcing entirely, but the resulting customer figures will not represent lifecycle energy consumption. When the customer conducts a full calculation, the omission will become a trust issue. At a minimum, clearly disclose the existence and boundary of outsourced processes and state that the reported figures exclude them.
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