Mustafa Yılmaz
Founding Director
Pusulay Mühendislik ve Danışmanlık

Energy consumption, which constitutes the largest operating expense in compound feed production after raw material costs, has become the most critical agenda item for feed mills in line with narrowing profit margins and carbon emission targets. In these facilities where electrical and thermal processes are intensively carried out, correct engineering optimizations to be implemented in grinding and pelleting lines, which hold the vast majority of total energy consumption, both unlock the door to sustainable production and radically reduce operating costs.

Compound feed production is one of the industrial processes that require high energy consumption. While global feed production reaches approximately 1.44 billion tons annually, total compound feed production in Türkiye reached approximately 30.7 million tons as of 2025. This production volume places the feed industry as one of the most strategic, dynamic, and operationally intensive sectors of the agricultural and food supply chain.

In recent years, the increase in energy costs, national and international targets for reducing carbon emissions, and gradually narrowing profit margins have made feed manufacturers’ investments in energy efficiency and operational improvement projects even more crucial. Today, competitive advantage is directly linked not only to high production capacity but also to production systems that can use energy efficiently.

Energy constitutes the largest operating expense in feed mills after raw material costs. While approximately 60% to 70% of total energy consumption occurs in the pelleting process, this is followed by the grinding process in terms of energy consumption. Therefore, a significant portion of energy efficiency efforts is concentrated on these two processes.

In this article, the distribution of energy consumption on a process basis in feed mills, the main energy consumption points, and applicable energy efficiency methods are discussed. In addition, case studies and trial results obtained from different applications are evaluated comparatively, and recommendations for short, medium, and long-term energy efficiency strategies are presented. The evaluations and technical conclusions in the article mainly cover compound feed mills that produce ruminant and poultry feed.

ENERGY CONSUMPTION: TÜRKİYE AND GLOBAL OUTLOOK

Annual compound feed production worldwide is around 1.44 billion tons. Türkiye, on the other hand, ranks among the leading producer countries in Europe with approximately 30.7 million tons of compound feed production as of 2025. The share of the agriculture and livestock sector within the total energy consumption of Türkiye is approximately 3.5%, and the feed industry constitutes an important but limited part of this share.

Compound feed production is one of the energy-intensive industrial activities where mechanical and thermal processes are carried out together. The production process includes numerous operations using electric motors, mechanical equipment, and heat energy from raw material reception to the shipment of the final product. Total energy consumption for the production of one ton of compound feed generally ranges between 40 and 80 kWh/ton, depending on the process structure and product type. Approximately 20 to 50 kWh/ton of this consists of electrical energy, and 20 to 30 kWh/ton consists of thermal energy in the form of steam.

The utilization rate of renewable energy sources in the sector is not yet at the desired level. Therefore, most of the energy requirement is met from the electricity grid and fossil fuels such as natural gas and fuel oil. Increasing energy costs and targets for reducing carbon emissions have made energy efficiency one of the priority agendas of the feed industry.

ENERGY CONSUMPTION BY PRODUCTION FORMS

The amount of energy consumed in feed production shows significant variations depending on the physical form of the manufactured product and the processes applied. Additional operations such as grinding, conditioning, pelleting, and extrusion directly affect the total energy requirement.

Mash Feeds: This is the product group with the lowest energy consumption due to requiring no additional thermal processing. Electricity consumption is at an average level of 10 to 20 kWh/ton.

Pellet Feeds: Since steam, pressure, and mechanical energy are used together in the conditioning and pelleting processes, the energy requirement increases significantly. Electricity consumption generally ranges between 20 and 50 kWh/ton, and in addition to this, a significant amount of thermal energy is consumed.

Specialty and Pet Feeds (Extrusion): This is the production group with the highest energy consumption due to cooking, extrusion under high pressure, and drying processes. Total energy consumption can reach up to 100 kWh/ton depending on process characteristics, and can even exceed this value in some products.

ENERGY CONSUMPTION PROFILE IN FEED MILLS

Two different energy sources are mainly used in feed production processes: electrical energy and thermal energy. Electrical energy is used in grinding, mixing, pelleting, conveying, and operating auxiliary equipment, while thermal energy is used in processes requiring steam, primarily conditioning.

In a modern feed mill that includes both mash and pellet feed production lines, average energy consumption per ton of product occurs within the following ranges:

Electrical energy: 10 to 50 kWh/ton

Thermal energy (steam): 20 to 30 kWh/ton (approximately 20 to 30 kg steam/ton of product)

Total energy consumption may vary depending on production capacity, product formulation, pelleting ratio, equipment efficiency, and operating conditions.

When the distribution of electrical energy by process is analyzed, the pelleting line stands out as the process with the highest energy consumption in feed mills. Approximately 60% to 70% of total electricity consumption occurs in the pellet press and conditioning equipment. Therefore, the highest savings potential for energy efficiency improvements is found in this process group.

The pelleting line is followed by the grinding system, which accounts for approximately 15% to 20% of total electricity consumption. Conveying equipment (elevators, screw conveyors, chain conveyors, and pneumatic conveying systems) accounts for 5% to 10% of total consumption, and mixing and dosing systems account for approximately 3% to 5%. The remaining energy consumption is distributed among aspiration systems, compressors, lighting, auxiliary facilities, and other supporting equipment.

ENERGY EFFICIENCY STRATEGIES ON A PROCESS BASIS

Optimization in the Grinding (Crushing) Process

The grinding (crushing) process stands out as the second most intensive consumer of electrical energy in feed mills after the pelleting line. Energy consumption in this process is directly affected by raw material properties, target particle size, equipment condition, and operating parameters. In particular, as the targeted particle size decreases, specific energy consumption shows a non-linear (exponential) increase. Therefore, over-grinding finer than necessary both increases energy costs and accelerates equipment wear.

PROPER SCREEN AND HAMMER MANAGEMENT

One of the most important elements determining hammer mill performance is the operating condition of the hammers and screens. Worn hammers, dulled cutting surfaces, and clogged screens reduce grinding capacity while increasing motor load and causing energy consumption to rise. Field applications show that grinding efficiency can decrease by up to 50% in mills that are not properly maintained.

For this reason, periodically reversing or timely replacing the hammers, regular cleaning of the screens, and selecting screens suitable for the process requirement are of great importance. In addition, using screens designed with a high open area ratio and minimum dead zones ensures that the product passes through the screen in a shorter time, thereby reducing grinding time and the associated energy consumption.

AIR-ASSISTED ASPIRATION SYSTEMS

An effective aspiration system in hammer mills not only provides dust control but also directly improves grinding performance. Removing the hot air and moisture generated inside the mill facilitates product flow, reduces screen clogging, and lightens the load on the motor. Thanks to a properly designed aspiration system, energy consumption of the mill motor can be reduced by 5% to 15%.

In order for the aspiration system to operate efficiently, jet filter air pulse valves, filter bags, and fan performance must be checked regularly. One of the most reliable methods for these checks is differential pressure measurement. Continuous monitoring of filter inlet and outlet pressures allows for the correct tracking of filter clogging status and air flow rate in the system, contributing to the planned execution of maintenance activities.

USE OF VARIABLE FREQUENCY DRIVE (VFD)

Raw materials used in feed production such as corn, barley, wheat, and soybean meal have different characteristics in terms of hardness, density, and breakability. Since mills operating at a constant speed cannot achieve the same performance for all raw materials, unnecessary energy consumption can occur.

The use of a Variable Frequency Drive (VFD) on hammer mill motors allows the rotor speed to be optimized according to raw material properties. Thus, not only is electricity consumption reduced, but the target particle size is also obtained more stably, and product quality is improved. This application is evaluated as one of the effective solutions that increase both energy efficiency and product homogeneity, especially in mash feed production lines.

USE OF A PRE-MILL DUST SCREEN

Separating fine particles with a dust screen before grinding reduces the amount of material entering the mill and prevents unnecessary grinding. Thus, the operating time of the mill is shortened, the motor load is reduced, and significant savings are achieved in total energy consumption.

Application and trial studies carried out in different enterprises reveal that the use of a pre-mill dust screen can provide energy savings at the level of 10% to 15% in the grinding process. In addition, increasing equipment capacity, extending hammer and screen life, and reducing maintenance costs are among the important secondary benefits of the application.

SELECTION OF MILL SCREEN DIAMETER AND PREVENTION OF OVER-GRINDING

The screen diameter used in the grinding process is one of the critical parameters that directly affect both the targeted particle size of the product and energy consumption. Using screens with a smaller diameter than the process requirement causes the material to remain inside the mill longer, prolonging the grinding time and increasing electricity consumption accordingly. In addition, over-grinding finer than necessary accelerates equipment wear, increases maintenance costs, and adversely affects production capacity.

Therefore, screen diameter and hammer configuration should be determined in accordance with the target particle size and the intended use of the product. Appropriate screen selection and timely hammer-screen replacements both increase grinding efficiency and contribute to reducing specific energy consumption.

In trial studies conducted, it was determined that using a 4x4 mm screen instead of a 6x6 mm screen resulted in an approximate 20% reduction in mill capacity, while causing an approximate 14% increase in electricity consumption. These results demonstrate that grinding finer than required by the process not only lowers production capacity but also significantly increases energy costs.

Application Note: Every additional grinding operation performed below the target particle size does not make a meaningful contribution to feed quality in most cases, while increasing energy consumption and equipment wear. Therefore, screen diameter selection must be optimized not only for product quality but also for energy efficiency.

Grinding Process – Summary

The grinding process stands out as the second most intensive production stage in terms of electrical energy consumption in feed mills after the pelleting line. Energy consumption in this process is directly affected by target particle size, screen diameter, the condition of the hammers, aspiration performance, and raw material properties. Over-grinding finer than necessary reduces production capacity while increasing electricity consumption and equipment wear.

In terms of energy efficiency; proper screen and hammer management, an effective aspiration system, the use of a variable frequency drive (VFD), pre-mill dust screen application, and selecting screens suitable for the target particle size are prominent improvement areas. Application and trial studies show that energy savings between 5% and 20% can be achieved in the grinding process with these optimizations, and significant operational gains such as capacity increase, reduction in maintenance costs, and extension of equipment life can be obtained as well.

In conclusion, correct engineering applications to be carried out in the grinding process not only reduce energy costs but also make significant contributions to production capacity, product quality, and operational sustainability. Therefore, grinding optimization should be considered as one of the priority focus areas of energy efficiency efforts in feed mills.

As Pusulay Engineering and Consultancy, we analyze processes for enterprises operating in the feed sectors with 21 years of sectoral knowledge and engineering approach, and provide consultancy services focused on engineering, operations management, and efficiency.

Particularly, we continue to serve and contribute to enterprises in the feed sector with our applications such as shrink management, energy efficiency, operating costs optimization, capacity increases, breakdown and downtime improvements, field audits, feed mill investments, feasibility, regional market analyses, and operational SWOT analyses.