Energy intensity development of the German iron and steel industry between 1991 and 2007

The iron and steel sector is the largest industrial CO2 emitter and energy consumer in the world. Energy efficiency is key to reduce energy consumption and GHG emissions. To understand future developments of energy use in the steel sector, it is worthwhile to analyze energy efficiency developments over the past two decades. This paper analyses the development of the specific energy consumption (SEC) (measured as primary energy use per unit of product) in the German steel sector between 1991 and 2007. We found that the total SEC declined by 0.4%/year. Of this 75%, or 0.3%/year, is due to a structural change towards more electric arc furnaces (EAF). Energy efficiency improvement accounts for about 25% of the observed change in SEC, or 0.1%/year. Energy efficiency improvements are found, especially in rolling (1.4%/year). The net SEC of blast furnaces decreased due to increased top gas recovery by 0.2%/year per tonne iron. Improvements in other processes were very limited or non-existent. In basic oxygen furnaces (BOF) net SEC increased due to a 60% decrease in BOF gas recovery between 1993 and 2007. In EAF and sinter plants the SEC remained constant or, respectively, even increased by 9% between 1991 and 2007 per tonne sinter.

► Analysis of data on the energy consumption per major process.
► Total energy intensity declined by 0.4%/year.
► Total energy intensity declined by 0.3%/year due to a structural change towards more electric arc furnaces (EAF).
► Energy efficiency in the major processes did not improve significantly apart from rolling (1.4%/year).
► Specific net energy consumption of blast furnaces decreased due to increased top gas recovery by 0.2%/year per tonne iron.