(1)Senior Researcher, INESC TEC
(2)Senior Researcher, INESC TEC
The path towards a carbon neutral and circular industry poses immense challenges, but there are also opportunities - more flexibility, increased self-consumption, and less dependency on volatile fossil fuel and electricity markets. To fully benefit from these opportunities, companies need to consider optimisation of production plans and energy efficiency improvements. New digital tools, such as the multi-objective advanced planning and scheduling, can be particularly useful in providing an optimised compromise between fulfilling delivery dates and minimise overall energy consumption.
The world of tomorrow, today
The energy transition carries with it the promise of a smarter, greener, fair, and (almost) waste-free world. However, this will require a major overhaul of our economies as more than 80% of world’s energy use is supplied by coal, crude oil, and natural gas. And, with few exceptions, by imported fossil resources.
At the EU-27 level, the transition aims to reduce current levels of greenhouse gases (GHG) emissions by 50% in the next ten years and to reach carbon neutrality by 2050. On paper, the main strategy looks straightforward - full decarbonisation of electricity and heat production alongside massive electrification of the energy use in buildings, transportation, and industry. Additional sectorial strategies are also envisioned for hard to abate sectors, such as the production and use of green hydrogen for industry and long-haul transportation, and the integration of carbon capture and use for industrial processes emissions.
The (sustainable) future of industry
In industry, characterised by an heterogenous structure – i.e., some sectors are dominated by few big companies, while others are more fragmented, with many small and medium enterprises (SME) -, and a variety of products, production processes and systems, the full decarbonisation and electrification face considerable challenges.
Only one third of the energy use is associated with driven systems (e.g., compressed air, ventilation, refrigeration), which are already mainly powered by electricity. The main energy need, covering the other two thirds, is in the form of thermal energy for processes and other thermal needs.
Half of this corresponds to high temperature processes with (currently) limited potential for low carbon options. The other half has a wider spectrum of options, from direct integration of solar thermal energy and industrial heat pumps for lower temperatures, to replacing fossil fuels with hydrogen and bioenergy for medium range temperatures. Notably, as 20 to 50% of the heat production is lost as waste heat, there is a significant potential for immediate energy efficiency improvement through heat recovery and reuse.
While there are few commercial options for hydrogen-based technologies, or limited approaches to high temperature processes, recovering and reusing waste heat, integration of local renewable sources – solar photovoltaic (PV) or thermal -, and using heat pumps to either replace or boost lower temperature processes, have viable commercial alternatives already, which could contribute significantly to the industrial energy transition.
This new ecosystem of low-carbon options will also allow lower dependence on volatile fossil fuel and electricity prices, reduce operational energy costs, and increase the availability of flexible assets (e.g., thermal and electrical storage, heat pumps, electrolysers). Moreover, it will require a new generation of digital tools to allow better management of the increasing variability and flexibility of local industrial energy systems.
Energy costs @ industry
Energy - traditionally considered an indirect cost in industry - now places important challenges to those who depend on it to produce goods, on account of its rising costs, and type (solar, electrical, gas, etc.) and offer (solar energy production forecasts, electrical energy daily cost profiles, etc.) variability. In order to remain competitive in regional and global markets, managers need, more than ever, to find ways to balance operating costs against profitability, which is an especially difficult task for SME.
Operational efficiency vs Efficiente use of Energy
Industrial companies have carried out major actions to improve their operational efficiency, acting upon predictive maintenance, setup and changeover minimisation, human resources upskilling and adequate selection and use of manufacturing execution system (MES), enterprise resource planning (ERP) and planning and scheduling tools.
Energy efficiency is essentially achieved using more recent, more productive and efficient machines and ancillary equipment, although further improvements may be achieved through the use of planning and scheduling tools. The vast majority of SME do not have the capability to renew all their productive resources and, as such, one frequently witnesses a mix of distinct generations of machines capable of producing the same products and their variants at the shop floors.
Faster, more energy efficient machines do not always mean faster changeovers; towards fulfilling all customer orders, all machines, old and new, must be used to full extent.
So, what do we need and how do we come up with a production plan (allocate and sequence production orders in machines) that’s both optimised for customer service and uses energy in an efficient way?
Challenges to achieve energy efficiency in industry
Data acquisition models and policies that support decision-making and keep our information secure need to be properly designed and implemented, as they are crucial to achieve operational and energy efficiency. This usually implies deploying an industrial Internet of Things (IOT) platform. Industrial companies need to know their machines, products, and process characteristics and how they relate to energy consumption.
A production plan that’s globally optimised for customer service and efficient use of energy is often not optimised at machine level. We need to increase the acknowledgement of this duality among human resources who often have difficulty in understanding why production orders on their machines are no longer properly ordered, in their opinion.
We need to implement, when and as much as possible, flexibility on when operations are performed depending on energy availability and tariffs. Without this flexibility, there will be not enough freedom to obtain better solutions.
Opportunities that arise from knowing your production system and properly use energy offer
Being able to correctly characterise the processes and production systems’ energy consumption characteristics, together with information on current and forecasted product demand and energy offer and prices, will allow the use of tools such as Multi-objective Advanced Planning and Scheduling to obtain solutions that provide an optimised compromise between fulfilling delivery dates and minimising overall energy consumption.
The energy demand profile resulting from these optimised solutions will allow more sustained negotiation of energy purchases and emphasise the company role within renewable energy communities.
Industrial companies will be able to increase margins or be more competitive. They’ll also be more resilient and face variability with knowledge and confidence, adapting production plans.