UZWIL, SWITZERLAND — Energy prices have virtually exploded in the last two years and have become an even more important cost factor in the milling industry. Having experts examine their mill for energy-saving opportunities and drawing up a specific plan for implementing the savings measures identified — including a precise cost-benefit calculation — is highly recommended, according to Switzerland-based milling equipment manufacturer Bühler AG.

The cost structure of an average large mill (daily capacity of 500 tonnes per day) in 2020 was about 74% raw materials, 7% capital, 7% distribution, and 12% processing. About 4% of the processing costs were for energy. Consequently, measures to reduce energy consumption primarily were motivated by environmental policy rather than by financial considerations. 

This situation has changed radically in the last 18 months. The price of a kilowatt hour (kWh) of energy has risen from just under €0.20 to over €0.40 during this time. This means that the proportion of energy costs in relation to the total costs of a mill has more than doubled, increasing to 10% from 4%. And according to the forecasts of industry associations, a return to the “old” energy prices in the longer term is not expected as there is talk of a price of €0.20 to €0.25 per kWh. 

After the recent cost hike, the 2022 energy bill for the 500-tonne-capacity-per-day mill, in our example, looks like this: assuming an energy price of €0.15 per kWh in 2020 and €0.35 per kWh in 2022, this results in additional costs of €2.2 million for 240 days of annual operation and a consumption of 92.4 kWh per tonne. If the total controllable energy consumption was reduced by 10%, €388,000 could be saved annually. This has made “saving energy” a management-level issue. 

Energy savings assessment

One of Bühler’s main goals is to supply machines, processes and plants that are as energy efficient as possible. For many years, Bühler also has been helping its customers to save energy in warehousing, production, and distribution. In association with experts from the Bühler affiliate Bühler + Scherler AG, which specializes in electrical engineering, building automation, and project management for medium and large companies, the electrical engineers and technologists from the Bühler service team have assisted many customers with services for planning and implementing energy-saving measures. 

This assistance now is being taken to the next level with a comprehensive service offering through an Energy Saving Assessment (ESA). 

The ESA consists of four steps. An initial assessment is carried out remotely. This is crucial for planning an on-site visit. In the second step, a team of two experts spends approximately a week at the customer’s mill. During this time, they subject the entire process to thorough tests and measurements to detect energy-saving potential, analyzing everything from leaks in the compressed air system to process optimization and system upgrades. 

The Bühler electrician focuses on identifying savings potential in all electrical devices/equipment, while the process technologist takes care of identifying opportunities for improving energy efficiency by means of process optimization and equipment maintenance or upgrades. Particular attention is paid to pneumatics and aspiration because the production of air is extremely expensive in terms of energy compared to other processes. 

Thorough data analysis

After the on-site visit and measurements to gather the required data, Bühler experts carry out a thorough data analysis and compare findings to industrial best practices. The Bühler expert team then identifies energy-saving possibilities and estimates the feasibility and actual savings potential based on the customer’s production requirements.  

The savings potential is presented to the customer and an implementation plan is drafted based on the customer’s priorities. The implementation plan highlights critical conditions and includes risk mitigation measures to ensure the achievement of the estimated savings. 

If the customer prefers to reduce the initial cost of implementation and to mitigate the risks related to sustaining optimal performance, Bühler can offer a performance-based implementation plan. In the performance-based model, the project is in principle financed by the savings achieved.