11 May 2023: The pulp and paper industry shares the twin challenge of high energy prices and a need to decarbonize. Across industry, over 90 percent of business leaders believe that rising energy costs threaten their business’s ability to compete, according to an ABB survey from March 2023. The data also reveals that businesses expect lower profitability and plan to cut investment in essential areas such as research, people, marketing, and infrastructure. Concerningly, the research also found that energy prices may impact Net Zero targets – 58 percent of businesses say they may have to move their goals back by as much as five years.
Investing in energy efficient solutions is an effective way for businesses to address the energy crisis and stay on track to reach their sustainability goals. In the pulp and paper sector – like most industrial sectors – electric motors are a major consumer of electricity, and many are old, inefficient models. Replacing old motors and using variable speed drives (VSDs) are straightforward ways that facilities can significantly improve their energy efficiency.
There is also a strong financial case for upgrading. Electricity is typically a top operating expenditure (OPEX) for paper and pulp facilities, so more efficient equipment provides a way to directly save money. While energy prices remain high in some regions, the payback period for these upgrades is shorter than ever.
However, an average pulp or paper mill may have hundreds of electric motors, each with unique operating parameters and loading patterns. Choosing which motors to upgrade can be a challenge – but support is available.
Identifying energy saving solutions
A traditional energy audit involves an expert visiting a site, manually gathering data and analyzing it. They will then provide recommendations. However, this can only test a limited number of motors due to its manual nature – typically only the largest and most critical ones. This makes it hard to identify opportunities for improving energy efficiency that lie beyond the large motors on a plant’s critical line.
Fortunately, new technologies enable operators to do an energy efficiency assessment of a broad range – or even all – of the motors across a site. During a digital energy audit, also known as an appraisal, a mill’s own operators gather data digitally from connected motors and VSDs. The data is then uploaded to the cloud where an expert reviews it remotely.
The expert calculates how much energy is wasted by motors operating inefficiently, identifies motors that are operating far from their peak efficiency, and recommends solutions. For example, they may provide an estimate of the potential return on investment (ROI) from upgrading to newer, more efficient motors or adding a VSD. They may also suggest adjusting the operating parameters so a motor only operates within the range where it is most energy efficient.
Data gathered digitally can also reveal ongoing information about the condition, performance and health of a mill’s motors. Operators can use this insight to inform a condition-based maintenance strategy – reducing unplanned downtime by fixing problems before they become an issue.
The value of a digital energy audit in practice has already been well established. For examples, we can look to two mills in Sweden.
Improving energy efficiency at Waggeryd Cell
Waggeryd Cell is one of the world’s most modern, energy efficient BCTMP (bleached chemi-thermo-mechanical pulp) mills. Every year, it produces 190,000 tons of BCTMP from wood chips for use in paperboard, tissue, and paper production.
The operators were keen to achieve even greater energy efficiency, so they conducted a digital energy audit. Around 100 digitally connected motors at the mill sent data to the cloud. A service expert analyzed it remotely and found that ten motors were operating inefficiently and several more were oversized for their application.
An onsite energy audit may have missed these motors. Fortunately, with all of the data from the energy efficiency assessment, Waggeryd was able to prioritize the replacement of six of the least efficient motors.
Cutting energy use for SCA Group
Elsewhere in Sweden, SCA Group’s kraft paper mill in Munksund produces 400,000 tons of packaging every year. The operators are dedicated to sustainability, and the mill has used bioenergy to reduce its reliance on fossil fuels to under 5 percent. To further improve efficiency, the operators wanted to identify and upgrade the least efficient units in their fleet of 2,400 electric motors to cut total energy use by 50 GWh per year.
Service remote expert analysis of data from the mill’s connected equipment produced several recommendations for improving efficiency, including upgrading motors, changing their operating regimes and adding VSDs. The expert also provided estimates on the cost and potential ROI from each of these changes, and SCA decided to upgrade several motors, achieving their ambitious energy saving target. The old motors were sent for recycling in line with SCA’s circularity goals.
The SCA team is also using condition monitoring data to review the reliability and availability of its machinery. This data enables the operators to optimize mill performance and perform condition-based maintenance.
A proven, data-driven approach
The energy crisis and the global push to reach Net Zero mean that investing in energy efficiency is now more important than ever for having less industrial emissions. Fortunately, the digital energy audit makes it easy to identify inefficient equipment, determine which changes will have the biggest impact and develop a financial case for upgrading. The service sits alongside remote condition based monitoring to enable businesses to make smarter maintenance decisions to increase uptime.
While these two Swedish companies were early adopters of the energy audit service in the paper and pulp industry, they are not alone. The service has proven its value and it is now used by mills worldwide, enabling operators of all kinds to increase energy efficiency, reduce emissions, and save money.
By Mari Haapala, Digital Lead of ABB Motion (www.pulpapernews.com)