Measuring process efficiency for environmental impact reduction

The degree to which we can both measure and simulate process parameters and the resultant energy efficiency is growing steadily and goes hand in hand with increased automation of the stages of manufacturing. Coriolis Composites was established in 2000 with efficient, automated composite manufacturing as their goal. They are now a leading provider of Automated Fibre Placement (AFP) machines, with headquarters in Brittany, France. As Alexandre Hamlyn, Chief Innovation Officer, explained in the JEC World “Less is Better” conference forum, their machines allow for putting material exactly where it is needed with precise fibre orientation corresponding to the stress requirements, with no or minimal scrap. Using less material through optimal fibre orientation and scrap reduction is the first step to environmental impact reduction where high embodied energy materials like carbon fibre are used.

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Coriolis uses low energy consumption robots, making lightweight end effectors as well as incorporating motors and heating devices to reduce energy as much as possible. The environmental impact reduction aligns with Coriolis’ motivation to reduce automation machine footprint. Their software solutions integrate design with AFP manufacturing to optimise mechanical properties and production rate while reducing design-to-manufacturing lead-time. The automated system and high frequency monitoring of process parameters allow for accurate measurement of energy in use, providing for sustainability assessments through LCA. But Coriolis is working on taking that further through virtual twin technology which will lead to enhanced ecodesign and enable the process to be optimised while still in the virtual space.

Hamlyn explains: “We already supply the software to allow our customers to design the best part to be produced with our robots. Soon we will provide the software to calculate the energy consumption that will be used in production, so the user will be able to assess different designs with the energy consumption as an indicator. It’s not only lightweighting, it’s not only the price, but it’s also the energy consumption.”

The Composite Technology Center / CTC, an Airbus subsidiary in Stade, Germany has also been focusing on energy evaluation in production. Detailed data is needed to make production processes more efficient, and so more sustainable. In fibre reinforced composite production, electrical energy and heat flows as well as compressed air and vacuum flows are particularly relevant. CTC has developed a modular, expandable, mobile measuring system, including evaluation software, for the simultaneous recording of an entire system, as well as its components, e.g. individual motors. This system provides data for LCA as well as identifying potential for optimisation and energy saving.

Jan Ohm is leading this activity at CTC. Ohm says: “In aerospace the lifetime of the product is very long, so the lifetime of the production systems can be even longer. Most of the machines used today were built when energy was not the main specification criteria. Data on machines’ energy demand is important for optimising older machines, so as to provide value to current systems, and can be used in LCAs, to provide value to future systems.”

Over time, measurements capture longer-term effects such as seasons, fluctuations in machine use and the effect of wear and tear. In-depth understanding of processes is enabled by measuring individual components. The data can be analysed in different ways, for example as a hierarchical energy value stream which highlights hotspots and allows for optimisation of energy use. CTC uses Polaris VSM Value Stream Modeler from iFAKT which can organise the digitised information and combine sections of the value stream, group sub-processes and gain an overview without losing the detail.

These approaches provide accurate ways to optimise processes, and integrating the data into an LCA can provide further useful insights. There may be several reasons for undertaking an LCA:

• Benchmark: To provide overall cumulative energy demand (CED), carbon footprint data or other impact categories for a product, e.g. for an Environmental Product Declaration (EPD)
• Comparison: To compare products against one another, e.g. manufacturing by traditional prepreg and autoclave vs AFP or heated tooling, or with different material choices
• Prioritisation: To highlight areas of high impact, enabling prioritisation for rapid impact reduction
• Payback: To compare manufacturing impact with impact through the use phase, e.g. Is it worthwhile to use higher impact carbon fibre to reduce weight and so save fuel emissions through life, or to use a high performance coating to extend the life of a product?
• Cost: To evaluate economic cost against environmental cost at stages of the life cycle

A full LCA can be costly and time-consuming, as much of the impact may be in raw materials extraction and processing, and accurate data is difficult to collect. However, environmental impact databases exist, such as ecoinvent, and there are simplified LCA tools available.

The European Composites Industry Association (EuCIA) has developed a simplified LCA tool for composites, the Eco Impact Calculator. This is a free, easy-to-use, online tool which enables composites companies to calculate the environmental impact associated with the production of their products. It uses a transparent and uniform methodology following ISO 14040/044, assessing production from cradle to gate, i.e. from raw material extraction until the product leaves the factory “gate”.

The data is based on EU averages. Peer reviewed industry-based material data is used, and process data has been averaged from EuCIA member companies. Where industry data is not available, some materials and processes, such as raw carbon fibre production, are modelled, based on first principles following real industry practices.

EuCIA launched the most recent update of the Eco Impact Calculator at JEC World 2023. The update enables users to take advantage of the latest environmental data and software, drawing from the ecoinvent 3.8 database. Data can be exported in the form of an Eco Report listing three sustainability indicators in the latest formats: carbon footprint (Greenhouse Gas Protocol v 1.02); cumulative energy demand (CED v 1.11); and International Reference Life Cycle Data System sustainability score (ILCD 2011 Midpoint+ v 1.09 / EU-27 2010). The data can be downloaded for import into the SimaPro LCA software (9.3.0.3) to allow for full life cycle calculations.

Airborne has used the Eco Impact Calculator to inform the design and manufacturing process. At the JEC World “Less is Better” forum Marcus Kremers highlighted the need to design for sustainability. “Current designs are optimised for traditional design, such as strength, stiffness, fire performance, and so on”, explains Kremers. “It is very important to implement simplified LCA in the design process, also taking materials and manufacturing solutions into consideration.”

Like Hamlyn, Kremers is also convinced that software and robotics are an important part of the solution. He gives the example of Automated Ply Placement (APP), that enables the use of new material formats coming to the market especially around recycled and bio-based materials. These new materials also need new automation methods.

A very important metric is to reduce the waste, and where possible to use the offcuts in a secondary product. Software and machine learning can optimise material usage. “Reusing what we have is important in our thinking for the future” says Kremers, “and there is also a business case to be made. If you take the current carbon price of the European ETS system of about 100 Euro/tonne, and we use the data of the EcoCalculator of EuCIA, then carbon fibre has already 4-5 Euro/kg as carbon tax. And this will increase in the future. If automation can save waste, then it can pay for itself.”

Kremers has recently started a new initiative called Eve Reverse, in which the goal is to manufacture truly carbon-negative products, which have more CO₂e captured during the growth phase of the bio-based materials than emitted during manufacturing, and that have a long lifetime to store the CO₂. They combine natural fibres and biobased polymers with new processing technologies to create durable, high performance composite products. To achieve the goal of making carbon-negative products, the design and full manufacturing chain needs to be highly optimised to minimise the material and energy use throughout all the manufacturing steps, from raw material to end product.

A particular challenge to obtaining accurate LCA data is transparency in the supply chain. The Eve Reverse vision is excellent, but for the time being the raw materials used to make composites are typically energy intensive, and mostly based on petroleum feedstocks and mined resources. In carbon fibre manufacturing, both the precursor production and the conversion to carbon fibre are high energy processes which are beyond the influence of most composite part manufacturers. 

Merlin Theodore is Director of the Carbon Fiber Technology Facility at Oak Ridge National Laboratory in Tennessee, USA. Theodore says “It is critical to work with everyone across the supply chain and have an integrated vision. We should be intentional in our requirements for using and obtaining sustainable metrics.” She notes that the lack of transparency in the supply chain means that a lot of the data available can only be used qualitatively. “As we integrate practices across the supply chain, that will help to give us better information and develop tools that can give us quantitative data.”

It was noticeable at JEC World 2023 that sustainability was a key feature in discussions. Everyone is talking about it, but still relatively few are rigorously measuring and calculating environmental impact. However, as the organisations mentioned in this article demonstrate, the tools to do this are now available in several areas, and, as Theodore says, working together across the supply chain will facilitate gathering more accurate data, and sharing good practice. This will enable the industry to highlight the areas that need to be worked on to progress towards a more sustainable future for composites, and ultimately to truly carbon-negative composite solutions.

* Including energy use, freight transport and direct emissions from raw materials.  Hannah Ritchie, Max Roser and Pablo Rosado, “Emissions by sector”, OurWorldInData 2020 https://ourworldindata.org/emissions-by-sector