The iron and steel industry is a highly energy-intensive industry. The use of energy and process coal in the iron and steel industry accounts for about 15 per cent of Swedish industry’s total energy consumption. This works out at 20–25 TWh on a yearly basis. Since the energy is a central and expensive raw material, the continuous work carried out to streamline processes and utilise the residual energy has made the iron and steel industry into an energy-intensive industry.
Energy supply is a central parameter in the development of the steel industry’s operations. Increasing demands from customers for tighter delivery timetables and customised products place heavy requirements on production planning and flexibility in order, at the same time, to ensure efficiency. This presupposes that the supply of energy is reliable, both in respect of quality and volume. This applies to all energy carriers such as coal, gas and electricity. Where electricity is concerned, the quality requirement is for the electricity system to supply sufficient output and at a stable frequency. For certain processes, a short voltage drop or frequency deviation means that the equipment becomes damaged which can result in an extensive production shutdown. The high temperatures and many process stages also imply that the steel industry is not able to rapidly adjust to variations in the energy supply such as access to electricity.
Energy efficiency measures – different aspects
For the steel industry, the work with energy efficiency encompasses different elements that must be handled in different ways but which all contribute to making the steel production as efficient as possible.
Long-term joint research
The high-temperature processes consume the major part of the energy and it is in this area that the main resources are invested to enhance the efficiency of the energy use. The development is supported by long-term research where new technology is produced and tested. Subsequently, major investments are often required for the technology to start to be used.
- Research programme Iron and Steel Industry’s Energy Use – Research and Development (JoSEn)
- Jernkontoret’s Technical Area 51, Energy and furnace technology
Continuous maintenance and improvements
Support oriented processes comprise e.g. pumps and fans required for cooling and ventilation. In this context, it is the continuous work with maintenance and the deployment of resources for development, in small steps, that drives forward the efficiency improvement process. In connection with major investments new technology can also be introduced and system optimisation carried out.
Utilisation of residual energy
Since the steel production process includes many phases of heating and cooling there is also scope for utilising residual energy. This is done through the heat either being used internally e.g. for heating or drying processes, or through the heat being conveyed out into the local district heating network. Energy-rich process gases are also obtained from the blast furnace process which are then utilised to produce electricity and heating.
The many sub-processes involved in steel production also means that production planning is an important element to ensure the efficiency of the whole process. Different products need processing of varying amounts or heat treatments of varying length. The most efficient solution, of course, is where the production equipment, especially in hot processes, can operate fully the whole time.
Energy efficiency measures at the steel utilisation phase
The greatest scope for efficiency gains, nevertheless, is probably when the steel produced is actually used for end products. In this context, a specially customised steel can mean the use of the steel in the end product becomes more efficient, a car becomes lighter or a tool lasts longer. Consequently, product development is perhaps the best efficiency-enhancing measure.
SKGS – energy co-operation of Sweden’s base industries
SKGS stands for Skogen, Kemin, Gruvorna och Stålet (Forests, Chemicals, Mines and Steel) and is a collaboration between the industry trade groups of the energy-intensive base industries: Swedish Forest Industries Association, Innovation and Chemical Industries in Sweden (IKEM), Swedish Association of Mines, Mineral and Metal Producers and Jernkontoret.
The interests of the base industries are represented by SKGS e.g. through:
- working to ensure that political decisions deliver a competitive operating framework, such as the electricity supply situation in Sweden being stable and offering competitive electricity prices.
- contributing actively to the energy debate through submitting comments on official reports.
- using different media actively and bringing different problems to the attention of members of the Swedish Parliament.