Ilgaz Unal
Milling Technologist and Grain Milling Consultant
Un-Al Milling Consultancy Foreign Trade Co. Ltd.

As power costs rise and margins come under pressure, controlling specific energy consumption has become a strategic issue that directly affects profitability, competitiveness, and long-term plant performance. This article explores the hidden sources of energy loss in modern mills and explains why real savings often begin not with new equipment, but with smarter process design and deeper operational optimization.

In today’s milling industry, energy has become far more than a routine operating cost. It is now a critical performance factor that shapes how efficiently a mill can run, how competitively it can price its products, and how sustainably it can operate in the years ahead. Yet many of the biggest energy losses in flour mills remain hidden behind familiar systems and long-established practices. Oversized machinery, poorly designed product flows, inefficient aspiration, idle running, and unnoticed compressed air losses can all quietly erode performance. Identifying and correcting these hidden inefficiencies can unlock substantial gains in both energy efficiency and overall milling performance.

1. Energy as a strategic lever: From cost factor to a matter of survival

Looking at economic indicators over recent years, we see the curve of energy costs climbing steeply across all sectors. For the energy-intensive milling industry, this development has dramatic consequences. The continuously rising base price per kilowatt-hour puts massive pressure on profit margins, transforming the topic of energy efficiency from a mere trend into a genuine matter of survival.

In modern milling, a specific energy consumption of 55 to 60 kWh per ton of milled grain is considered the benchmark for an efficient operation. In daily practice, however, a drastically different picture often emerges. Faulty project engineering, inadequate plant planning, or simply outdated concepts drastically increase energy demand. In such poorly designed mills, consumption values exceeding 70 kWh per ton of wheat are not uncommon.

This supposedly small difference accumulates to massive sums in a 24-hour operation. The result: The significantly increased operating costs not only erode the mill’s profitability but inevitably reflect directly in the prices of the final products. A mill that cannot control its energy processes will inevitably lose its competitive edge in the market.

2. The real energy consumers: Symptom treatment vs. root cause analysis

Of course, standard industry cost-saving measures have now reached many facilities. Upgrading all plant lighting to LED technology, utilizing energy-efficient motors (IE3, IE4), and implementing variable frequency drives (VFDs) are important steps. However, this is often merely treating symptoms on the surface.

The true core of the problem lies deeper: The fundamental incorrect sizing of the core machinery. A glaring amount of energy is wasted, particularly by the main consumers—the roller mills and the high-pressure fans for the pneumatics. When examining the actual production capacity, the same picture almost always emerges in practice: Very large, oversized motors are used, rarely operating in their optimal load range. In addition, the machinery park is often simply too large for the targeted tonnage—too many machines are being used for too little product.

The root of this massive inefficiency usually lies in the fundamental planning phase. The entire milling diagram flow and the machine settings are often designed incorrectly from the ground up. Modern grain mills are frequently planned with extreme overcapacities, leading to continuous idle runs and energy losses during operation.

Yet, the fundamental task of an efficient mill is clearly defined: Intelligent product management, precise sifting, and accurate grinding, including the perfect roll gap setting. Uncovering these deep-rooted sources of error absolutely requires an in-depth on-site analysis by experienced milling experts.

3. The vicious circle of faulty product management: Quality loss and energy waste

Another fundamental error observed in many existing mills relates to sifting and product management (passage distribution). These are often fundamentally misdesigned. Due to a faulty diagram design, products of different granulation and quality, which technologically do not belong together, are unnecessarily mixed.

The consequence: These incorrectly mixed passages must be repeatedly and entirely unnecessarily ground, sifted, and transported pneumatically. These redundant cycles trigger a devastating chain reaction. They put extreme strain on the pneumatic system, occupy valuable sieve frames and sifting areas, and lead to continuous overloading of the roller mills. This artificially inflates electricity consumption and causes massive energy losses.

Simultaneously, this unnecessary machine load drastically reduces the hourly capacity of the entire plant. Ultimately, the final product also suffers greatly from this faulty process: Continuous and incorrect over-grinding significantly deteriorates flour quality, manifesting directly as an unwanted increase in the ash content.

4. Inefficient aspiration: Dust problems and wasted fan energy

Another glaring weak point in many existing plants is the aspiration system used for dedusting the entire mill. Very often, these vital systems are misdesigned and poorly planned from the start. Fans and filter systems, which are actually supposed to ensure a safe and dust-free working environment, operate completely inefficiently due to flawed engineering.

Practice shows: Machines are often not properly aspirated. As a result, suction lines and pipes regularly clog. The fans consequently run unnecessarily at full capacity under high load, consuming massive amounts of electricity, yet remaining completely ineffective at solving the actual dust problem. Here, valuable energy is literally wasted into thin air. To stop these massive losses and ensure a functioning dedusting system, a rational, aerodynamically correct planning and expert implementation of the entire aspiration architecture is absolutely essential.

5. The leverage effect of plant optimization: Higher yield at constant consumption

When discussing energy savings, a crucial factor is often overlooked: Increasing the process efficiency of existing plants. Let’s look at the existing machinery and motor park of a currently running mill.

Through targeted, in-depth optimization of the process management, the diagram structure, and precise machine settings, the extraction rate and hourly capacity can be increased by 20% to 25% in many cases.

The fascinating part is: The absolute energy consumption of the entire mill remains almost constant during this performance increase. To put it plainly: Based on the critical indicator—the kilowatt-hour per ton of milled wheat—the facility achieves a real energy saving of over 10% simply through this optimization.

Since entire machinery parks do not need to be repurchased, but rather the existing potential is fully utilized, the costs for such interventions amortize in an extremely short time (fast ROI). However, this type of process optimization is not a standard intervention. It requires tremendous precision and deep, accumulated milling know-how.

6. Beyond milling: Pneumatics and logistics as overlooked factors

Energy evaluation must not stop at grain milling alone. A holistic approach must imperatively analyze downstream processes, such as flour storage and the continuous transfers of products. Every unnecessary transport route and every redundant elevation of material drives up operating costs.

To make these processes more efficient, all pneumatic conveying routes must be rethought. Roots blowers (positive displacement blowers) play a central role here. In many facilities, these units operate as massive, often overlooked energy consumers. Incorrect calculation of pressure requirements or inefficient pipeline routing literally causes money to be blown into the air here.

Optimizing this area energetically requires exact calculations of air volumes and line resistances. Creating a well-thought-out conveying concept and putting it into practice is a masterpiece of milling engineering—but it is not magic. With the appropriate expertise, a massive relief in the energy balance can be achieved.

7. Smart automation: The role of sensor technology against ıdle running and energy waste

A massive, yet often invisible problem in many facilities is unnoticed idle running times. Particularly during the transfer and vertical conveying of products (elevators and pneumatics), it is extremely common for plant components to run completely empty because there is no product flow at that moment. Since these transport routes are often not intelligently monitored, large motors continue to run unnecessarily, causing enormous energy costs.

Here lies a gigantic savings potential that can be unlocked through modern automation and targeted programming. Today, critical machines and plant sections can be monitored very precisely and specifically. The key to this is the installation of sensor-based detection mechanisms at strategic bottlenecks and critical points of the mill.

Through intelligent PLC programming, this sensor data is processed in such a way that idle runs, impending blockages, or partial failures are detected in real-time. The plant can thus be operated fully controlled and on-demand: If the product flow stops, the control system automatically shuts down or throttles the corresponding transport lines. This not only drastically increases plant safety but conclusively eliminates unnecessary energy consumption caused by idle running.

8. Chain reactions from lack of maintenance: Smart filter control as a performance guarantor

Beyond pure idle running, there are other critical mechanisms that can trigger devastating chain reactions throughout the entire mill—often caused by wear and tear, creeping blockages, or simply skipped maintenance intervals. The filter units of the pneumatic and aspiration systems are a classic example of this.

If the cleaning of the filter bags (pulse-jet cleaning) lacks intelligent monitoring and control, these bags will inevitably clog. The consequence: The pneumatic or aspiration system can no longer deliver the desired performance. To overcome the increasing line resistance and still meet the pneumatic demands of the entire plant, the systems are forced to expend disproportionately more power.

Smart control systems provide a targeted remedy right here. They ensure that the filter bags are cleaned properly and on demand, optimizing and minimizing the required purging air generation. The compressors or roots blowers used for this air turn into massive energy wasters when forced to fight blindly against clogged filters. The most critical aspect of this scenario is: While energy consumption rises due to such internal system resistances, the hourly capacity of the entire plant simultaneously drops dramatically.

9. Compressed air losses: The exorbitantly expensive sound of hissing valves

Another extremely critical point in the milling industry, which is frighteningly often tolerated in practice, is unnoticed compressed air losses. Damaged air lines, leaking pneumatic cylinders, or worn two- and three-way valves cause expensively generated compressed air to continuously escape.

This leads to a fatal and costly cycle: To compensate for the constant pressure drop in the network, the compressor is forced to run continuously at full capacity. It relentlessly tries to produce new compressed air that is instantly lost through the leaks. This is pure energy waste, and therefore the entire compressed air network must imperatively and continuously be checked.

The most effective and logical method for this is actually surprisingly simple: The acoustic inspection during plant standstill. When the mill is shut down—for example, on the weekend—but the compressors and the compressed air network are still pressurized, a maintenance representative must systematically walk through the entire facility. By simply listening carefully, air leaks and the typical “hissing” sound of defective valves or hoses can be precisely located. Replacing or sealing these leaking elements immediately relieves the compressor significantly, providing instant, measurable savings on the electricity bill.

Conclusion: Green technologies and the first step for tomorrow

When we speak of “Green Technologies” in milling, it rarely involves utopian future concepts in practice. The greenest technology is the prevention of waste. A facility that maximizes its yield through intelligent process design and minimizes specific energy consumption through exact sizing acts in a highly sustainable manner while simultaneously protecting its profit margins.

To the question of what a mill manager should change first thing tomorrow morning in their factory to increase energy efficiency, the practical answer is this: Do not blindly buy the next more efficient motor. Start with a ruthless assessment of your diagram and your pneumatics. Have experts check whether your machines are oversized for your actual tonnage and whether your roll grinding gap is truly optimally set. The greatest savings potentials are often not found in the catalogs of machine manufacturers, but are hidden directly in the heart of your current process.