Industry is one of the sectors with the highest energy consumption and is also one of the least efficient, especially with regard to the use of energy in the form of heat. This fact becomes especially critical in the current energy crisis situation, where a winter is expected in which rising energy prices can lead to situations of serious uncertainty.

In this scenario, the increase in renewable energy sources, storage and energy efficiency in industry is one of the main challenges identified by the European Commission to face the crisis.

The tip of the iceberg

July 2021. The world was waking up from a long period of low activity due to COVID-19 and the sudden increase in energy demand, coupled with low renewable production and the policy of increasing the cost of coal, triggered a tsunami that shook the economic foundations of our society.

Energy prices experienced a significant increase. However, this was only the tip of the iceberg, because all these factors were compounded by the invasion of Ukraine in February 2022, with disastrous consequences for energy prices. While the price of natural gas for an average industrial consumer in 2021 rose from 23.9 €/MWh, to 41.6 €/MWh (+74%), in August 2022 it reached an all-time high standing at 316 €/MWh (+1222%).

As a consequence, many industries have had to rethink their cost structure and business model, as energy costs have gained significant weight. This increase has been so rapid and unexpected that some of the energy-intensive industries have had to stop or regulate their production, as recently announced by Sidenor, ArcelorMittal and Nervacero.

It would be unfair to say that the industrial sector has not made efforts to improve energy efficiency and reduce its dependence on fossil fuels. In fact, energy efficiency has been labeled as the first fuel towards decarbonization.

The parameter used to measure energy efficiency at the macro level is energy intensity, which relates energy consumption to GDP. The latest data available to be able to assess the variation in energy intensity correspond to the period 2000-2017. In this period, and mainly due to the various crises that have been faced, it should be noted that energy consumption in European industry fell by around 15%. However, energy intensity fell even more, standing at 27%, observing a generalized decrease in all industrial sectors.

These improvements have generally been achieved through low-investment, high-cost measures, many of them driven by energy audits. Among these measures are the replacement of lighting fixtures, the substitution of machines or installations for more efficient ones, insulation or operational improvement measures derived from the monitoring or control of installations...

However, when it seems that the industry has done its homework, several studies still show a potential for improvement ranging from 19% to 27%, depending on the type of industry or sector. What remains to be done?  

One answer to this question is the reuse of heat in industrial processes.  

Every day the industrial sector, which is desperately trying to reduce its energy consumption, discharges huge amounts of energy into the atmosphere in the form of waste heat, mainly because it has not yet found a cost-effective way of using it. This is no small matter, given that energy-intensive industries use more than 50% of this energy to produce heat, and once the heat has served its purpose, between 20% and 50% is lost to cooling towers or directly to the environment.

The biggest challenge that generally hinders the recovery of this energy is the impossibility of making the collection of excess heat coincide in time with another process where this heat can be reused. The problem can be solved theoretically with the installation of a heat storage system. However, until now, the investment costs have pushed the payback period beyond the limits that the industrial sector can afford.

In recent years, however, CIC energ¡GUNE researchers have focused on developing a low-cost, modular, high-performance storage technology to enable, among other things, industrial waste heat recovery and constitute the next and final leap in improving industrial energy efficiency.

ArcelorMittal was one of the pioneers in the use of this technology, first in the framework of the European H2020 ReSlag project and then in the LIFE HI4S project, coordinated by CIC energiGUNE. In turn, Iresen has also made use of this technology in a solar concentration plant, installed in Morocco and in which CIC energiGUNE collaborated in the ORC-Plus project.

In short, taking into account the horizon of energy instability that is foreseen in the short term, CIC energiGUNE makes available to the industry the knowledge developed in thermal storage technologies, with the aim of contributing to the reduction of energy consumption and minimizing the impact of the endless increase in the price of fossil fuels.