What is it about?

The opportunities and challenges to reducing industrial energy demand and carbon dioxide (CO2) emissions in the iron & steel sector are evaluated with a focus is on the situation in the United Kingdom of Great Britain and Northern Ireland (UK), although the lessons learned are applicable across much of the industrialised world. It is the largest industrial sector in the UK in terms of energy demand and ‘greenhouse gas’ (GHG) emissions, and accounts for some 26% of GHG emissions from British industry. Current Best Available Technologies (BAT) will lead to short-term energy and CO2 emissions savings in iron & steel processing, but the prospects for the commercial exploitation of innovative technologies by mid-21st century are far more speculative. The attainment of significant falls in carbon emissions over the period to 2050 will depend critically on the adoption of a small number of key technologies [e.g., energy efficiency techniques, fuel switching towards bioenergy, and carbon capture and storage (CCS)], alongside the decarbonisation of national electricity supply.

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Why is it important?

The iron & steel industry is the largest industrial sector in the UK in terms of both energy demand and GHG emissions, and accounts for some 26% of GHG emissions from British industry. There are large differences between industrial sub-sectors in the end-use applications of energy, especially in terms of products manufactured, processes undertaken, and technologies employed. It is clear that the basic metals sub-sector, of which iron & steel is by far the most dominant sub-sector, gives rise to the third largest industrial energy consumption in the UK; caused principally by high temperature heating processes (85%) and, to a lesser extent, electrical motors (4%). The blast furnace is at the core of its operations, which reduces iron ore (Fe2O3) at high temperatures into iron (Fe) with the use of carbon as a chemical reductant. Subsequently, iron is then converted into steel, which is cast and finished to produce a number of industry outputs (including ingots, slabs, sheets, plates, bars, rods and sections) consumed by a wide range of downstream industries. These encompass, for example, construction, motor vehicles, metal fabricating industries, and consumer goods. Steel is also produced from scrap, and is arguably the most recycled and recyclable material on the planet. The iron & steel sector overall depends on a high throughput of natural resources with energy costs making up a significant proportion of its total production cost. The sector has always been highly energy conscious, and has made significant improvements to efficiency over the years. Today the sector is also subject to a raft of government regulations designed to stimulate GHG emissions reduction in order to mitigate global warming, i.e., a legally binding UK target of an 80% reduction by 2050 against a 1990 baseline (although the British Government has asked its independent advisors – known as the Committee on Climate Change (CCC) - to consider the implications of Britain becoming ‘net-zero’ on the same timeline). Industrial leaders believe that there is only limited room left for improvement based on existing technologies.

Perspectives

The blast furnace is the most efficient energy conversion process in the sector, but also the largest energy user and consequently a priority target for energy demand reduction. Many existing technologies could reduce a significant proportion of process energy loss, e.g., heat recovery at the coke ovens, sinter plant, and electric arc furnace, and further heat and gas recovery from the basic oxygen furnace. The uptake of key BAT technologies for hot-rolling could reduce sector primary energy by 18% and GHG emissions by 12%. Further potential may be available for blast furnace operation by optimising chemical transfer to minimise blast furnace gas (BFG) production. Nevertheless, there are a number of non-technological barriers to the take-up of such technologies going forward. Other radical process technological innovations (such as the ‘electrowinning’ or so-called HISARNA process) are likely to be available in the longer term.

Professor Emeritus Geoffrey P Hammond
University of Bath

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This page is a summary of: Industrial energy use and carbon emissions reduction in the iron and steel sector: A UK perspective, Applied Energy, September 2019, Elsevier,
DOI: 10.1016/j.apenergy.2019.04.148.
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