Pulp Paper & Logistics


ABB 13


Figure 2: The ABB Ability Energy Manager dashboard


such as education and financial incentives, iDSM enables plant operators to utilise key assets when energy demand is small and supply is large. There are three main ways in which iDSM creates value for the paper mill. Firstly, it facilitates the scheduling of production that is highly energy-intensive during off-peak hours when energy prices are lower, a principle known as load-shedding. A prerequisite to this approach is to have occasional excess production capacity in the operation, allowing some flexibility in scheduling. With this approach, the mill builds production reserves during off-peak hours, for example performing heavy refining of stock during these hours and holding the stock in storage tanks for later use during peak hours. In a sense, this becomes stored energy in the process. Secondly, it helps mills to sell


energy back to the grid when the mill is a net producer of energy and when energy prices are high. The plant must be connected


to the electricity grid to take advantage of price volatility on the spot market in this way. Thirdly, it helps to automatically


forecast energy demand, which allows mills to buy with more favourable pricing by purchasing on the day-ahead markets instead of the intraday markets. Contracts between the mill and the utilities must be structured to allow for this.


These methods not only reduce


energy costs, but also increase the opportunity to use more renewable energy. Fossil-fuel- based energy produced during peak hours is the least efficient and most expensive. The portion of renewables is often higher when producing during off- peak hours, due to supply and demand dynamics. Figure 1 shows the sources of potential for optimisation.


Managing energy usage with iDSM It is possible that companies might attempt to manage some


Optimising operations also has the potential to change the mindset within mill management, encouraging them to abstain from entrenched working practices in favour of increased flexibility when planning production where possible, resulting in more efficient overall energy use


portions of energy use manually by monitoring energy prices and coordinating production to align


when energy prices are lowest. This would depend on a mill’s ability to implement buffers (like a pulp tank between a pulp line and a paper machine) and the flexibility to stop and start production swiftly, in line with energy price volatility. However, this approach is difficult, if not impossible, because there are so many conditions that have to be monitored and optimised at the same time. At the Mayr-Melnhof Karton (MMK) cartonboard mill at Frohnleiten in Austria, for example, it has 800 such conditions, so manually collecting the required data would be impractical as typically this has to be done every 15 minutes. Fortunately, software solutions


exist to overcome these exacting challenges. ABB Energy Manager, for example, is a scalable, modular software solution that applies iDSM theories and uses real-time data from process monitoring, automation and production planning systems – coupled


4 September/October 2019


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