Effects on global CO sub(2) emissions when substituting LPG with bio-SNG as fuel in steel industry reheating furnaces-the impact of different perspectives on CO sub(2) assessment

• Published in: Energy efficiency 2016-12, Vol.9 (6), p.1437-1445
• Main Author: Johansson, Maria T
• Format: Article
• Language: English
• ISSN: 1570-646X; 1570-6478
• DOI: 10.1007/s12053-016-9432-0

The iron and steel industry is the second largest user of energy in the world industrial sector and is currently highly dependent on fossil fuels and electricity. Substituting fossil fuels with renewable energy in the iron and steel industry would make an important contribution to the efforts to reduce emissions of CO sub(2). However, different approaches to assessing CO sub(2) emissions from biomass and electricity use generate different results when evaluating how fuel substitution would affect global CO sub(2) emissions. This study analyses the effects on global CO sub(2) emissions when substituting liquefied petroleum gas with synthetic natural gas, produced through gasification of wood fuel, as a fuel in reheating furnaces at a scrap-based steel plant. The study shows that the choice of system perspective has a large impact on the results. When wood fuel is considered available for all potential users, a fuel switch would result in reduced global CO sub(2) emissions. However, applying a perspective where wood fuel is seen as a limited resource and alternative use of wood fuel is considered, a fuel switch could in some cases result in increased global CO sub(2) emissions. As an example, in one of the scenarios studied, a fuel switch would reduce global CO sub(2) emissions by 52 ktonnes/year if wood fuel is considered available for all potential users, while seeing wood fuel as a limited resource implies, in the same scenario, increased CO sub(2) emissions by 70 ktonnes/year. The choice of method for assessing electricity use also affects the results.