Carbon footprint a big challenge
CLIMATE CHANGE Technological improvements continue to help the energy intensive sector reduce greenhouse emissions, writes Rebecca Weisser
THE imperative to reduce greenhouse gas emissions is a major challenge for the global steel industry. Carbon is an essential ingredient in the chemical process of making steel and greenhouse gas emissions are an unavoidable waste product.
The global steel industry is working cooperatively on radical carbon dioxide reduction technology but breakthrough technology using a reductant other than carbon to make steel and thereby produce steel with zero carbon dioxide emissions is years if not decades away.
According to the Australian Steel Institute, the energy and greenhouse gas intensity of steel production has decreased by an estimated 40 per cent in the past quarter century through technological improvements and introduction of continuous casting. Nonetheless steel production is still highly energy intensive with energy representing up to 40 per cent of the cost of steel production.
After consultation with industry, the federal Government has committed to developing a national emissions trading scheme but both Australia’s steelmakers, Bluescope and OneSteel, have expressed similar concerns.
In a submission to the Government, Bluescope noted that ‘‘ any emissions trading scheme potentially compromises the competitiveness of Australia’s steel industry’’ and that ‘‘ this will likely lead to increasing imports of steel products from non- carbon constrained countries, and drive future investment in steelmaking offshore.’’
OneSteel noted the Australia competed with ‘‘ a number of developing economies that are subject to less stringent greenhouse constraints’’ and that ‘‘ a discrepancy in greenhouse gas policy would place the Australian iron and steel industry at a significant disadvantage relative to its international competitors’’ which could lead to a migration of production to countries with no greenhouse gas emissions constraints and an increase in greenhouse gas emissions per tonne of steel made.
Bluescope also wrote that if the Government decided to proceed with a stand- alone emissions trading scheme ‘‘ then a fundamental design feature must be compensation by the free allocation of long- term permits to energy intensive and trade- exposed emitters such as BlueScope Steel.’’
A major initiative of the Australian Government in developing an international response to climate change has been to create the Asia- Pacific Partnership on Clean Development and Climate or AP6 which brings together Australia, the US, China, India, Japan and the Republic of Korea. AP6 Partner countries account for 57 per cent of the global production of crude steel and this is expected to increase with the rapid economic development of China and India.
The AP6 Steel Task Force has developed a number of objectives to respond to the challenge of reducing greenhouse gas emissions. The first is to develop relevant benchmark and performance indicators for member countries. The key mechanism to reduce greenhouse gas emissions will be through the development and transfer of best practice steel technologies which will reduce energy usage, air pollution and carbon dioxide emissions from steel production.
One of the most straightforward ways of reducing emissions is through recycling. In 2005, the AP6 Steel Committee estimated that almost 43 per cent of global crude steel production came from recycling. However, the rate varies significantly between countries and products.
David Ryan, National Manager Marketing for the Australian Steel Institute says Australia has world class recycling rates. The Australian Steel Institute estimates that the average recovery rate for Australian scrap steel building materials is around 85 per cent and for structural steel the recovery rate is as high as 95 per cent, which matches world’s best practice.
Good design can also leverage the intrinsic qualities of steel reducing environmental impacts. Andrew Marchbank, the chairman of the sustainability committee for the ASI, says the existing steelwork at Chifley Tower in Sydney was modified to accommodate a more energy efficient airconditioning system and to add internal stairs to reduce the use of lifts. Whole structures can also be designed for re- use. For example, the Sydney Aquatic Centre was designed to be demounted after the Olympics and was relocated to the WIN Stadium in Wollongong.
Another way of reducing the greenhouse gas emissions in steel production is to reduce the greenhouse gas emissions of energy providers. Steel- making can make a contribution through the creation of valuable coproducts. Bluescope Steel has already begun work on a feasibility study for a cogeneration electricity plant at its Port Kembla steelworks which would use byproduct gases given off by steel- making to generate up to 120 megawatts of base load electricity and up to 220 MW if peaking capacity is added, saving an estimated 800,000 tonnes of greenhouse gas emissions from entering the atmosphere every year, the equivalent of taking 185,000 cars off the road.
Steel co- products can also reduce the carbon emissions of other industries. Slags that would have been dumped in the past can be used in the cement industry to dramatically reduce CO emissions in cement production.
Australia is also engaged in the development of technology to reduce energy consumption in the smelting of iron ore to create hot metal and pig iron suitable for basic oxygen furnace and electric arc furnace steel making. HIsmelt Technology, a member of the Rio Tinto Group, has the potential to revolutionise the production of hot metal and pig iron, a key input in steel making, by offering lower operating costs, lower capital costs and lower environmental impact.
‘‘ We have a vision of 100 HIsmelt plants over the next 15 to 20 years,’’ Stephan Weber, the managing director of HIsmelt says. ‘‘ What is really exciting is that HIsmelt can be combined with geosequestration to reduce carbon emissions to 0.1 tonnes of CO per tonne of hot metal, a really dramatic reduction.’’ The global average is 2.35 tonnes of CO per tonne of hot metal.