Mitigating climate change and achieving industry-wide decarbonization by 2050 are critical challenges for humanity. Energy-intensive industries that rely mainly on fossil fuels are compelled to reshape their energy systems and production processes to achieve climate neutrality by adopting innovative low-emission technologies and approaches. Given the need for a swift transition toward sustainable industries, it is crucial to develop effective methods that can accurately assess the sustainability potential of various measures at an early stage.
To ease the transition to climate-neutral energy systems, an integrated life cycle assessment (LCA) method was developed to comprehensively evaluate the environmental, economic, and energetic implications of sustainability measures. This method was developed and demonstrated based on research findings from specific sustainability approaches at four selected industrial sites in energy-intensive industries: pulp, paper, and print; chemical and petrochemical; cement; and magnesia. Within the integrated LCA framework, a scenario analysis is embedded to identify optimal solutions by varying design parameters such as energy supply alternatives, by-product use, or flexibility options. This allows for establishing an optimization hierarchy based on environmental, techno-economic, and energetic indicators, facilitating decision-making using multi-criteria decision methods. Given the expected increase in the share of renewable energy sources in the future, emissions from energy production are anticipated to exhibit greater fluctuations throughout days and seasons, making previous approaches based on aggregated annual values less accurate. To address this, the integrated LCA framework incorporates a novel dynamic energy modeling approach that considers the dynamics of energy generation and merges it with industrial load profiles, resulting in a time-resolved emission profile. This approach enables a more precise assessment of the ecological footprint of products, which is becoming increasingly important to customers.
The integrated LCA method was used for site-specific analysis in various industries. In the paper industry, the implementation of production flexibility and the integration of low emission technologies, such as storage, power purchase agreements (PPAs), electric boilers, and heat pumps, resulted in a greenhouse gas (GHG) mitigation potential of up to 32.3% per ton of paper. Energy costs were reduced by 44%, renewable primary energy demand (PED) increased by 156%, and fossil PED decreased by 32%. In the chemical industry, a GHG mitigation potential of up to 80% was achieved for 1 MJ of sustainable aviation fuel (SAF) compared with the fossil benchmark. This was accomplished by utilizing the by-product lignin as fuel and integrating renewable electricity. Renewable energy accounted for up to 82% of the PED. Utilizing all by-products was necessary to achieve exergetic system efficiencies of up to 57%. The cement industry demonstrated a GHG reduction potential of 245 tons of CO2 per GWh of recovered waste heat. However, waste heat utilization as process steam in a dairy in the proximity was economically unviable, regardless of whether thermal storage was implemented to balance supply and demand fluctuations. In the magnesia industry, a GHG reduction potential of up to 38.2% was achieved for producing 1 ton of MgO by co-firing locally available biomass with pet coke. The operational production costs could be decreased by 9.75%.
The examined case studies have demonstrated the importance of holistic assessments for industrial implementations of novel low-emission technologies and sustainability approaches. Although the eventual goal is decarbonization, the viability of the measures depends on their economic feasibility. Therefore, the accurate quantification of various indicators is crucial, and using multi-criteria decision-making methods can help strike a balance among different considerations. However, future flagship projects and success stories will be pivotal in driving industrial transformation and facilitating replication of measures, ultimately leading to a climate-neutral and prosperous European Union.