Case studies

Untapped energy efficiency potential in the plastics industry, opportunities to increase profits

10.08.2023.
5 mins

"Like many other companies, the unexpected rise in energy prices has prompted us to look at energy metering and energy efficiency options. We have found a system that not only measures our consumption, but also directly contributes to lowering the cost of our production, thus increasing our profits. I've been with the company for 13 years, but I never felt that my colleagues had a complete overview of our energy saving potential," - says the company's managing director

In this case study, we present an injection moulding company with 80 employees and a turnover of HUF 3 billion, who saved €30,000 in a single year by implementing an energy management system.

An energy management system is a set of tools and processes that enable companies to manage and control energy production and consumption more efficiently in their operations. Such systems enable energy-intensive manufacturing companies to analyse their consumption data and optimise operational processes to reduce energy use and costs. Solutions are also available today that take the burden of analysis and, for example, fault detection off the shoulders of colleagues, supported by artificial intelligence.

Injection moulding machines are highly energy-intensive machines, with a rated power typically in the range 20-110 kW, which is usually determined by the injection volume, among many other factors. It is worth noting that in most cases these machines are not yet equipped with a metering device or, if they are, these meters are not capable of storing data, but only of displaying the actual power or consumption.

It should be pointed out that in Hungary, since 1 January 2023, it has been mandatory to equip all machines with a rated power of more than 50 kW with an electricity meter that can also store data (so-called sub-meter), but surprisingly, companies need the metering not primarily because of the obligation, but rather for business reasons.

For the present example, a total of 21 sub-metering points have been installed in the company. Injection moulding machines with a rated power of less than 50 kW, as well as other equipment serving the site (e.g. compressors, pumps, fans, etc.), were also equipped with meters that

  • The data is stored in the cloud at 5-minute intervals;
  • can be installed under voltage, so they can be installed without disrupting production;
  • communicate independently of the site's local IT network; and
  • the data analysis software for the meters uses artificial intelligence for evaluation and possible alarms;
  • they are remotely accessible from almost any mobile device.

Wenerate's energy management system was chosen because it gave them the ability to continuously monitor the energy consumption and performance of the injection moulding machines, as well as many other energy parameters. The implementation of the system has allowed them to identify areas where they can improve efficiency and reduce energy consumption, and to receive alerts in case of abnormal consumption values, thus detecting faulty machine operations.

Injection moulding machine in use

Injection moulding machine in use

The energy management system immediately informed the company that phantom consumption occurs in the injection molding machines, as they are operated at suboptimal times or modes. Astonishingly, for an injection molding machine with a nominal power of 80 kW, they found that the equipment incurs energy costs ranging from 15 to 24 euros during operation, considering an electricity cost of 0.29 euros/kWh. This means that operationally, the electricity cost accumulates to 0.25-0.4 euros per minute. In the first week following the introduction of the energy management system, they detected 117 minutes when the equipment exhibited phantom consumption, meaning it was turned on without performing any production activities. Thus, during these 117 minutes, they unnecessarily paid out electricity costs of 40 euros for just one injection molding machine. Extrapolating this to 50 weeks - or an average year for them - resulted in savings of 2000 euros for a single piece of equipment.

In addition to specific, immediate energy savings, the Wenerate energy management system has demonstrated numerous other advantages. For instance, the company was able to identify anomalies related to voltage, as the system automatically sends alerts about voltage deviations beyond the tolerance range. Besides preventing machine failures, real-time monitoring of voltage is essential because while consistently high values result in additional costs, production efficiency remains unchanged.

Continuing with the previous example, if the injection molding machine with a nominal electrical power of 80 kW operates at a voltage of 400V and a current of 125 A, assuming a power factor of 0.95, sustained operation at 5% higher voltage can result in additional costs of up to 1-1.5 euros per hour for the company, considering an electricity cost of 0.29 euros/kWh.

Their introduced sub-metering system differs from other sub-metering systems available on the market in that the associated software allows measurements to be assigned to specific equipment types, thus fully leveraging all possibilities inherent in artificial intelligence (AI)-based analysis. Equipment-specific AI-based consumption analysis, among other things, can filter out consumption characteristics indicative of malfunction. The specific company saw the benefit of this AI-supported analysis when they received an alert during compressor measurements indicating that it was operating for more hours and at higher power than usual. Upon inspection, it was found that the fault was caused by a clogged air filter and improperly scheduled replacement. Thanks to immediate feedback and intervention, this also resulted in significant savings for the company.

Referring to the specific return on investment (ROI) of implementing and maintaining the Wenerate system, it can be concluded that the company incurs a cost of 22 euros per measurement point per month, which includes installation, setup, software usage, as well as operation, support, and warranty repairs during the contract period. In contrast, the achieved savings amount to 143 euros per measurement point per month, which is composed of the factors outlined in the article specific to the given site. This represents an exceptionally short payback period. The key to this is that, concurrently with the introduction of the energy management system, the company's colleagues and management are also committed to exploiting the energy-saving potential. After all, the software may point out faulty operation, excessive energy consumption, or specific waste, but intervention is futile without the company's openness to act. Increasing manufacturing efficiency and company profits generally serve the well-understood interests of all colleagues, as often annual bonuses or salary increases are based on such performance metrics.

The task of measuring cost reduction and profit growth is often carried out by the controlling or financial department. To facilitate their work, we have created the Wenerate API, through which data can be transmitted to popular enterprise resource planning systems such as SAP or Oracle. Furthermore, if the production department also requires access to the data, the Wenerate API can be integrated into most manufacturing execution systems (MES).


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