Reducing Risk and Cost of Renewable Energy and Improving Emissions Reduction Results

April 26, 2024

In the intricate landscape of process industries, energy emerges as the second-largest operating expense, trailing only that of raw materials. For most chemical and petrochemical plants, energy typically accounts for 50% of operation expenses. A change of 10% in energy cost can have a 5% impact on overall operation margins.

In the past two years, chemical industries and, metals and mining have taken a hit in margins due to the high fluctuation of energy costs in the market. And even though renewable energy costs are decreasing, they are still not as competitive as fuel energy prices in most regions, adding to the risk of availability. Addressing these challenges requires a transformative solution that seamlessly integrates business objectives with operational efficiency.

How can renewable energy be effectively incorporated into a complex utility system without increasing operating costs or reliability risks? Aspen Utilities Planner™ enables cost-effective and reliable operation and planning of utility systems, adeptly meeting the demands of production processes within the ever-shifting constraints of environmental, organizational and technical factors. It considers the availability, market price fluctuations and actual contracts with suppliers, allowing customers to incorporate internal and external sources of renewable energy into the supplier mix while mitigating the risk.  

The implementation of Aspen Utilities Planner has demonstrated significant benefits. Users experienced more than $170,000 savings/year in site energy costs and they have also been able to plan and optimize utilities to reduce CO2 emissions by ~60,000 tons in just one day. However, the magnitude of these benefits is site-specific, dependent on factors such as site complexity, size, and the implementation scope.

Purchasing agreements for accessing solar and wind energy with lower costs through Power Purchase Agreements (PPA)  can be planned by adding the variables of maximum availability and forecast availability per period into Aspen Utilities Planner. Different prices for different volumes of electricity purchases from day ahead market can be added for running optimization and identifying the best volume to purchase for each period of the following days.  

Aspen Utilities Planner optimizer editors enable all the variables associated with current purchasing contracts to be incorporated, including min and max price and availability, price peaks and periods expected, forecast of availability per period of time, different prices per volume of consumption, and they facilitate prioritization setting. Prioritization of contracts in optimization allows users to prioritize PPA contracts and helps avoid penalties and prioritizing renewable energy over fuel before consuming energy from the GRID or Fuel, allowing users to accelerate energy transition. When running the optimization, it will identify the best mix of volume to consume from each contract, the optimal operating conditions for the utility site. This is achieved by considering the efficiency and min and max load capacities of each equipment, availability, and driver selection, enabling delivery to utilities at the lowest operating cost. 

Aspen Utilities Planner can be run across multiple periods, optimizing each independently or as a sum, for planning a month, week or day. It allows users to change the frequency of the periods from minutes to hours to days, allowing for monthly operation planning as well as day ahead contracts and daily operating conditions planning. With this, many customers have realized savings of around 10%, allowing them to make their transition to renewables and helping to meet emission reduction targets.

Aspen Utilities Planner and optimization allows for the reduction of risk and overall costs associated with increasing renewable energy sources, for delivering the energy, steam and water required. When run together with Aspen OnLine®, Aspen Utilities Planner allows for utilities operation adjusting due to unplanned events.  Aspen Utilities Planner Online Optimization allows for reduced operating costs, emissions and steam venting, by adjusting in real-time the operation of a utility site when process demand reduces due to an unplanned event. It also allows for volume adjustments of additional energy sources required from the mix of contracts, adjusting to the slight gaps between planned and real renewable energy availability, as well as slight increases in energy demand, for identifying the optimal operating condition for delivering the utilities demand at the lowest cost.

With recent updates to Aspen Utilities Planner, customers can now calculate planned GHG Emissions and optimize their utility plant production plan for minimizing energy costs without exceeding emissions objectives, and for considering maximum emission limits across multiple periods. This enables reporting of planned and real-time optimized emissions at a composition layer (CO2, NOX and SOX) and provides the same report for your monthly plan.



The emissions node in Aspen Utilities Planner can be used for online real-time optimization with Aspen OnLine, ensuring users consider the up-to-date incurred emissions into the optimization. In addition, imports from incurred up-to-date emissions for the given period and the remaining time of the period can be used to calculate the new emissions Sox and CO2 flow maximum limits for running the real-time optimization. This ensure optimization considers not only planned emissions, but those that have already occurred in the previous hours or days of the month. This helps facilitate compliance with country regulations or company’s monthly or daily objectives.

This year is becoming pivotal with the rollout of the EU-CSRD (European Union Corporate Sustainability Reporting Directive), as well as legislation in California and New York and the US-SEC climate legislation (Securities and Exchange Commission). In addition, a range of standards are being launched to support the legislation, including ISSB’s (International Sustainability Standards Board) S1 and S2 and the European Sustainability Reporting Standards (ESRS) which underpins the EU-CSRD. Energy transition, emission accounting and reduction has become this year not only a goal, but a priority.

As companies and regulatory bodies continue to address the complexities of the energy transition, the tools in place to meet these new initiatives are vital to their success. Aspen Utilities Planner empowers forward-looking companies by providing valuable insight into real-time operation and supply changes that can have tangible effects across the value chain.

Note from the author: During OptimizeTM 24, we will be holding a two-day training for those interested in hands-on learning how to build your Aspen Utilities Planner Model for Optimizing both offline and online covering the use of personalizing constraints for limiting emissions, and the use of some of the Emission Blocks available.  If you are interested, please register for our Aspen

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