Unlike in the integrated steelmaking process, the greenhouse gas emissions related to electric arc furnace steelmakers come mainly from the use of electricity. While this gives the opportunity to reduce emissions by buying renewable energy, emissions can increase when such energy is in short supply.
SBB 21 February Outokumpu’s direct carbon dioxide emissions were up 45.6% year-on-year in absolute terms in 2010, Steel Business Briefing understands from the company’s annual report. A large part of the increase resulted from a 29.3% increase in stainless steel production.
However, a restricted supply of nuclear and renewable energy was also responsible for pushing these emissions up, the company tells SBB. The proportion of renewable and nuclear energy used fell to around 69% in 2010 from around 80% in 2009. Low water levels in Finland reduced the supply of hydroelectricity in the country and Sweden’s nuclear capacity was not connected to the grid for much of 2010, it notes.
Improvements in energy efficiency helped to counteract this effect somewhat: energy consumption per tonne of steel produced was reduced by 3% since 2007.
A reduction in secondary emissions from transport also contributed to a 0.3% reduction in combined direct and indirect CO2 emissions per tonne of steel. The company aims to reduce the total emissions per tonne of steel by 20% by 2020, as previously reported.
The company also managed to nearly double the amount of recovered metals from waste products to 80,408 t. The proportion of recycled and recovered scrap used per tonne of steel produced was nevertheless down from 94.5% to 91.1%.
Transparency on CO2 emissions is positive: all steel producers should be obliged to publish these and similar numbers by steel making location/operation. It would make the companies themselves more aware of the results of their activities. Its true that not a lot can be done in terms of emissions reductions in the short term, but some improvements in efficiency can be made. In addition, companies can estimate the impact of their products in terms of life cycle contributions, as Rautaruukki has done.
SBB 15 March Rautaruukki tells Steel Business Briefing that the small increase in the average tonnage of CO2 emitted per tonne of crude steel in 2009, compared with 2008, was due to the relatively low capacity utilisation rate in the year.
This meant that the Finnish company’s molten iron was produced less efficiently last year. Indeed it was below the minimum level necessary to ensure the efficient operation of the reduction process in the blast furnace, SBB was told.
According to figures in Rautaruukki’s annual report for 2009, the company produced 3.5m tonnes of CO2 and 1.9m t of crude steel in 2009. This gives an average of 1.85 t of CO2/tonne of crude steel, up from 1.78 t of CO2/t steel in 2008. The company’s goal is to improve the energy efficiency of production by 9% between 2005 and 2016.
Meanwhile, looking at the impact of Rautaruukki products as measured through their life cycle, the company says it reduced global CO2 emissions by 610,000 t. It did this by recycling steel and various mineral products. “Depending on the grade of steel being made, 20-30% of recycled steel was used in steel making,” it comments.
This cut in emissions reflects the specific range of products that Rautaruukki is currently producing. It highlights specialties for the construction and renewable energy sectors.