The climate impact of the iron and steel industry can be mitigated through increased energy efficiency, emission efficiency, material efficiency, and product use efficiency resulting in reduced product demand. For achieving ambitious greenhouse gas (GHG) mitigation targets in this sector all measures could become necessary. The current paper focuses on one of those four key measures: emission efficiency via innovative primary steelmaking technologies. After analysing their techno-economical potential until 2100 in part A of this publication, the current research broadens the evaluation scope for the crucial year 2050, based on a Multicriteria-Analysis (MCA). 12 criteria from five different categories ("technology", "society and politics", "economy", "safety and vulnerability" and "ecology") are used to assess the same four future steelmaking technologies in a systematic and holistic way in Germany, as one possible location. The technologies in focus are the blast furnace route (BF-BOF), blast furnace with carbon capture and storage (BF-CCS), hydrogen direct reduction (H-DR), and iron ore electrolysis (EW). These four technologies have been selected, as explained in part A of this paper, because they are the most commonly discussed technological options under discussion by policymakers and the iron and steel industry. The results of the current work should provide decision makers in industry and government with a long-term guidance on technological choices.
In 2050 the MCA shows significantly higher preference scores for the two innovative routes H-DR and EW compared to the blast furnace based routes. The main reasons being higher scores in the economical and environmental criteria. BF-CCS shows its greatest weakness in the social acceptance and the safety and vulnerability criteria. BF-BOF has the lowest economy and ecology score of all assessed routes, which is due to the projected high cost for carbon dioxide emission and increasing prices for fossil fuels. A first indicative trend assessment from today towards 2050 shows that H-DR is the preferred MCA option from today on.
Three exemplary weighting distributions (representing the perspectives of the steel industry, environmental organisations and the government), used to simulate different stakeholder angle of view, don't have a strong influence on the overall evaluation of the steelmaking routes. The results remain very similar, with the highest scores for the innovative routes (H-DR and EW). This leads to the conclusion that EW and in particular H-DR can be identified as the preferred future steelmaking technology across different perspectives.
Specific innovation efforts and dedicated programs are necessary to minimize the time until marketability and to share the development burden. The similarity of the MCA results from different perspectives indicates a great opportunity to reach a political consensus and to work together towards a common future goal. Regarding the pressing time horizon a concentrated engagement for one (or few) technological choices would be highly recommended.
Als eine der energieintensivsten Branchen wird auch von der Stahlindustrie ein Beitrag zum Klimaschutz erwartet. Da die bestehenden kohlebasierten Verfahren der Stahlerzeugung kaum noch Verbesserungspotential besitzen, kann langfristig nur über neue Verfahren ein großer CO2-Minderungseffekt erzielt werden. Die vorliegende Arbeit bewertet drei innovative Verfahren der Stahlerzeugung im Vergleich zur etablierten Hochofenroute. Die vergleichende Bewertung schließt nicht nur technische und betriebswirtschaftliche Aspekte, sondern auch gesellschaftliche, sicherheitstechnische und ökologische Aspekte mit ein und soll so eine ganzheitliche Einschätzung der neuartigen Verfahren ermöglichen. Die untersuchten Verfahren sind die Hochofenroute in Kombination mit Kohlenstoffabscheidung und -speicherung (CCS), die Wasserstoff-Direktreduktion und die Eisenerzelektrolyse. Die ganzheitliche Bewertung der drei Verfahren zeigt eine kläre Präferenz für die Wasserstoff-Direktreduktion als Zukunftsverfahren am Standort Deutschland, knapp gefolgt von der Eisenerzelektrolyse. Unter Verwendung dieser innovativen Methode könnte auch langfristig Primärstahl zu wettbewerbsfähigen Konditionen am Standort Deutschland produziert werden. Spätestens ab 2050 werden politische Rahmenbedingungen, steigende Preise für fossile Energieträger und Rohstoffe, sowie ansteigende Kosten für CO2-Emissionen voraussichtlich dafür gesorgt haben, dass die konventionellen Verfahren der Stahlerzeugung unattraktiv werden. Wichtige Voraussetzungen für die rechtzeitige Einphasung der neuen Verfahren sind eine konsequente Umsetzung der Energiewende und international verbindliche Klimaschutzziele sowie damit korrespondierende Anreizmechanismen.
At current primary steel production levels, the iron and steel industry will fail to meet the 80% emission reduction target without introduction of breakthrough technologies (Wörtler et al., 2013: 19). The current research analyses the technical and economical long-term potential of innovative primary steel production technologies in Germany throughout 2100. Techno-economic models are used to simulate three innovative ore-based steelmaking routes verses the reference blast furnace route (BF-BOF). The innovative routes in focus are blast furnace with CCS (BF-CCS), hydrogen direct reduction (H-DR), and iron ore electrolysis (EW). Energy and mass flows for the production of one tonne of crude steel (CS) are combined with hypothetical price, cost, and revenue data to evaluate the production routes economically, technically, and environmentally. This is a purely theoretical analysis and hence further external factors that may influence practical implementation or profitability are not considered.
Different future developments are considered by using three scenarios, representing an ambitious, a moderate, and a conservative transformation of the German energy sector. In general, looking into the future bares various uncertainties which should be reflected in a suitable manner.
According to the present scenario analysis, chances are that with rising prices for coal and CO2 allowances BF-BOF and even BF-CCS become unprofitable by mid-century. With a high share of renewable energy sources and high prices for CO2 allowances, H-DR and EW become economically attractive in the second half of the current century, when BF-based routes are long unprofitable. Energy and raw material efficiency is significantly higher for H-DR and EW and furthermore, the 80% reduction target by 2050 can be achieved in the ambitious scenario. However, high investment costs and high dependency on electricity prices prohibit a profitable implementation before 2030–2040 without further subsidies. EW is the most energy and resource efficient production route. Since continuous electricity is needed for the continuous operation, the electricity costs are 20–40% higher than for H-DR (with high-capacity hydrogen storage units). Even though hydrogen production implies efficiency losses compared to the EW route, the decoupling of hydrogen production from continuous operation of the steel plant through hydrogen storage offers the opportunity to use cheap excess renewable electricity. This makes the H-DR economically and environmentally the most attractive route and provides a crucial contribution to stabilize the grid and to store excess energy in a 100% renewable energy system.
