Two main environmental issues are affecting the steel making industry and other energy intensive industries:

• Climate change: the great use of energy obtained from fossil fuels and the often high level of its wastage due to technological limits make this sector one of the main contributors of global warming and a preferred target for international initiatives aimed at reaching the full economy decarbonization.
• Waste production and landfilling: iron and steel industries are highly intensive not only in energy but also in materials consumption, which leads to a great amount of solid waste (e.g. steel slag). The landfilling of slags is a significant source of pollution of air, water and soil, since it may release heavy metals for very long time periods.

LIFE HI4S project aims to tackle these problems by using waste heat contained in the off-gas of electric arc furnaces employed in steel making plants in three ways:

• To produce electricity able to guarantee self-consumption needs of the industry.
• Pre-heating scrap before its introduction into the melting furnace, reducing the amount of energy required to melt scraps.
• To heat steel slag, which will be used as a thermal energy storage system in order to obtain a continuous and homegeneous source of useful energy that can be managed on demand.

In this way LIFE HI4S introduces a technology able to boost energy efficiency and circular economy at once.

The new project technology will include an Organic Rankine Cycle (ORC) system developed by ENERBASQUE to produce electricity from heat waste. This system requires the use of a vector fluid that usually consists of fluorinated gases, having a very high GWP and thus being very dangerous from the climate change perspective. In the last years new, less harmful fluids are being developed and tested. Within the LIFE HI4S project, ENERBASQUE will evaluate the properties of these new fluids and one candidate of low GWP will be selected, increasing even further the fight to climate change.

The project started in July 2021 and will have a duration of 3 years and 9 months.