Reducing emissions in Animal Feed Production
Overview
The animal feed sector is the largest overall energy consumer in the EU food sector due to large volumes of over 160 Mt/year, despite low energy use per tonne (40–60 kWh/t). The most energy-intensive thermal process is Popping (Puffing), which requires very high temperatures, typically around 400 °C. Thermal energy makes up over 50% of total use and is traditionally generated by natural gas boilers. High-temperature Thermal Energy Storage (TES) systems, supplying process heat in the 300–500 °C range, can be a great solution for electrifying popping and roasting (150–200 °C), thereby reducing Scope 1 emissions.
Production Processes
The animal feed industry plays a central role in global food production, supplying balanced diets to livestock, poultry, and fish. Production begins with the reception of raw ingredients, which are weighed, tested, and checked for quality and safety. Nutritionists and scientists then design feed formulas tailored to different species. Once the recipe is set, the ingredients are ground, mixed, and processed into compound feed. Pelleting and conditioning are critical steps, as they shape the physical quality and digestibility of the feed.1
This process is highly automated in large industrial feed mills, while small farms often use simpler, batch-based systems. Batch production is still common at small scale, but continuous production is increasingly used in large feed mills because it is more efficient and better suited for high volumes.23
Energy Use in Animal Feed Manufacturing
On a per-tonne basis, the animal feed sector is considered a low to medium intensity energy user. However, the very large volumes produced make it one of the biggest overall energy consumers in the food industry. A typical feed mill consumes around 40–60 kWh for every tonne of compound feed, with an average close to 50 kWh/t when electricity and thermal energy are combined.5 About half of this energy use is electricity, which powers grinding, mixing, pelleting, and conveyors, while the other half is heat, mainly in the form of steam used for conditioning and, in some cases, drying.5 Pelleting is usually the most energy-demanding step, consuming up to 25 kWh/t, while grinding typically requires 6–10 kWh/t.56
Industrial heat in the animal feed industry is for example steam provides the heat needed to soften and condition feed material before pelleting. In some mills, steam use can account for as much as 50% of the total energy bill, especially where drying of ingredients is required.5
When this consumption is scaled up to European Union production levels of more than 160 million tonnes per year, the total energy demand is estimated at 46–59 PJ annually. This figure shows why animal feed, despite its relatively modest energy use per tonne, becomes the largest single energy consumer in the EU food sector. For comparison, dairy products typically require 200–300 kWh/t, bakery products 300–600 kWh/t, and meat processing 250–500 kWh/t, yet their total demand is smaller because their production volumes are lower.7
Since most thermal energy in feed mills is generated by natural gas boilers, direct fuel use accounts for a share of greenhouse gas emissions. According to the EEA, based on data from the EU ETS on emissions by country in 2019, the largest GHG emitters from the EU food and drink sector were: France (18%), Spain (13%), UK (10%), Poland (10%) and Italy (9%). The countries that had achieved the greatest GHG emissions reduction in this sector since 1997 are: Sweden (16%), Latvia (10%) and Finland (1%). Other countries have reported a GHG emissions increase in this period like Germany, Italy and Spain.7
How Thermal Energy Storage like Kraftblock can electrify processes in the animal Feed Industry
A range of thermal processes are used in feed manufacturing, each with different temperature requirements and nutritional effects. In simple cooking, grains are soaked in water and heated for 30 to 120 minutes, sometimes under pressure so that the temperature rises above 100 °C. This basic method is mainly used for whole or coarsely ground grains, but it is relatively slow and energy-intensive.
To switch from fossil fuels for this process, electrification is the cheapest option in large factories. An advanced method of electrification is a Thermal Energy Storage System (TES) like Kraftblock: it can provide process heat that uses electricity only from times of low-prices, thus drastically reducing the electricity cost. For cooking grains, heat pumps or small boilers might be the better choice, as TES is primarily for energy-intensive processes with higher temperatures.
Explosive cooking is a more advanced method where grains are exposed to high-pressure steam (2.3–3.0 MPa) and then suddenly released. The rapid pressure drop causes the grains to expand, which improves digestibility and texture.8
Thermal Energy Storage (TES) systems such as Kraftblock are particularly suitable, as they can supply the required process steam efficiently. By using electricity during low price periods, TES can drastically reduce energy costs while maintaining the high steam temperatures needed for explosive cooking.
Roasting is another important thermal treatment, especially for soybeans and oilseeds. In this method, grains are exposed to hot air in rotating drum dryers or fluidised beds at 110–170 °C. Roasting improves flavor and reduces anti-nutritional factors, although excessive heating can damage proteins.
Kraftblock can also provide significant advantages here: its air guided heat transfer system enables stable, high temperature air for uniform roasting, while optimizing energy efficiency.
Closely related is toasting, which is widely applied in oilseed processing. Here, steam is injected to heat the material to about 120 °C for 10–20 minutes, reducing compounds that interfere with protein digestibility and making the feed safer and more nutritious.8 Steam generation for this process can be integrated with the same electrification concepts discussed above. For more details on oil seed processing , refer to the dedicated article that explains the process in depth and highlights additional integration opportunities.
Dried Distillers Grains (DDGs) are a co-product of ethanol fermentation and are widely incorporated into animal feed. They are typically dried to below 12% moisture to ensure safe storage and handling before being shipped to feed mills. Since this drying process is carried out in ethanol production facilities rather than in the feed industry itself, the related energy use is attributed to ethanol manufacturing and not to feed processing.10
Thermal Heat Storage for Popping and Puffing
These processes all contribute to improving feed quality, but the most distinctive thermal treatment in animal feed is popping, also known as puffing. Popping relies on very rapid, high-temperature exposure to achieve a sudden expansion of the grain. This makes popping one of the most energy-intensive but also one of the most effective methods for improving starch availability, particularly in maize, which has the highest potential for expansion.9
Popping uses two main heat media:
- Direct Flame Popping: In this method, grains are placed on a hot metal plate or drum heated directly by a gas flame. Surface temperatures can reach 350–400 °C, and the kernels pop almost instantly on contact. This direct-fired approach is simple and fast, but it requires careful control to avoid burning.11
- Hot Air Popping: In this alternative, grains are exposed to superheated air in puffing tunnels or fluidised-bed dryers, typically at 200–300 °C. The hot air penetrates the grain, rapidly heating the moisture inside and causing it to flash into steam. Because there is no direct contact with a flame, this method provides more uniform expansion and reduces the risk of scorching.12
Following is a simplified version for the process of popping:
In both cases, Kraftblock can take over the heating part to supply the surface heat or hot air directly out of the storage system with optimized energy costs. In case of batch production, the storage makes energy purchase and popping process schedule completely independent from each other, allowing for the best possible energy costs.
Both popping methods rely on the same principle: once the internal moisture vaporises, the pressure inside the grain ruptures the kernel structure, creating an expanded, porous product. After popping, grains are often rolled or flaked to adjust bulk density and make them easier to handle in feed rations.13
Potential for Electrification with Kraftblock:
Electrification of feed processing offers a pathway to cut fossil fuel use, especially for high-temperature steps like popping and roasting. Thermal storage systems such as Kraftblock can supply stable renewable heat in the 300–500 °C range, matching the requirements of energy intense processes in animal feed production. Especially for larger operations with process heat grids, this is a path forward to transition away from fossil fuels. Albeit, many processes are lower temperature as well and can be supplied by an industrial heat pump. A closer look for each use case is required to make the best decision which technology can be used. In the Netherlands, frying potato chips was best to be electrified with Kraftblock, Read more about the PepsiCo project here.14
References
- American Feed Industry Association (AFIA). How Feed is Made.
https://www.afia.org/feedfacts/how-feed-is-made/#:~:text=Feed%20mills%20receive%20raw%20ingredients,ensure%20their%20quality%20and%20safety.&text=Nutritionists%20work%20side%2Dby%2Dside,for%20livestock%2C%20poultry%20and%20fish - Grand View Research (2023). Animal Feed Market Report.
https://www.grandviewresearch.com/industry-analysis/animal-feed-market-report - FoodDrinkEurope (2021). Decarbonising the European Food and Drink Manufacturing Sector.
https://www.fooddrinkeurope.eu/resource/decarbonising-the-food-and-drink-manufacturing-sector/ - Total Diet Composition Diagram. American Feed Industry Association (AFIA). How Feed is Made.
https://www.afia.org/feedfacts/how-feed-is-made/#:~:text=Feed%20mills%20receive%20raw%20ingredients,ensure%20their%20quality%20and%20safety.&text=Nutritionists%20work%20side%2Dby%2Dside,for%20livestock%2C%20poultry%20and%20fish
- Zetadec (2022). Reducing Energy Consumption in the Feed Mill.
https://www.zetadec.com/news/reducing-energy-consumption-in-the-feed-mill/22 - All About Feed. Energy Efficiency in Feed Mills.
https://www.allaboutfeed.net - CABI Digital Library. Heat Treatments in Feed Processing.
https://www.cabidigitallibrary.org/doi/pdf/10.5555/20133411906 - Kentucky Equine Research. Processing Improves Grain Digestibility in Horse Feeds.
https://ker.com/equinews/processing-improves-grain-digestibility-horse-feeds/c - Taylor & Francis Online. Drying of Distillers Grains.
https://www.tandfonline.com/doi/abs/10.1080/07373937.2011.649510 - Wiley Online Library. Direct Flame Roasting and Popping Methods in Food Processing.
https://onlinelibrary.wiley.com/doi/full/10.1111/jfpp.16891 - PubMed. Hot Air Puffing of Cereals in Fluidised Bed Systems.
https://pubmed.ncbi.nlm.nih.gov/33897009/ - Kraftblock (2022). PepsiCo Netherlands Project – VOLT Thermal Storage System with Eneco.
https://www.kraftblock.com/projects/volt