Energy demand of direct reduction furnace

costs_2035.csv の 1047–1048 行目から始め、⽔素直接還元炉の入力値を、引用されている MPP データおよび POSTED ソースと比較します。どの電力値と水素値が適切かを判断し、根拠に基づいて決定できたら、影響を受けるデータを更新します。

The energy demand of the direct reduction furnace seems a bit high.

Present data

For instance, take a look at lines 1047–1048 from costs_2035.csv:

Comparison

The plot below compares the following:

• PyPSA-tech-data: The data from the two rows above.
• MPP-documentation: The MPP documentation (referred to in the second row above), which only states 63 kg of H₂ per tonne of iron.
• MPP-steel-model: The MPP steel model input data (referred to in the first row above), visually separated as this refers to the combined process route of H2-DR and EAF.
• 8 other sources, of which most are academic journal articles. The data has been collected in POSTED.

Comments:

• The data assumed by PyPSA-tech-data is on the upper end of the range of values reported by various sources.
• Only Otto-2017 (Otto et al, 2017) assumes a similarly high value, however the work is a bit dated.
• I have higher confidence in Devlin-2022, Jacobasch-2021, and Vogl-2018, who all seem to assume much lower values (Devlin and Yang, 2022; Jacobasch et al, 2018; Vogl et al, 2018).
• I have been in exchange with Prof. Aidong Yang from University of Oxford. He confirmed that the still believes that the values he and his student reported in 2022 are still valid and that an electricity demand of no more than 0.5 MWh per tonne of DRI is feasible. He and his students are engineers, and they are regularly performing simulations of direct-reduction furnace operation.
• I will soon also reach out to colleagues from the industry and ask for feedback.

Interpretation

• Line 1047 in costs_2035.csv says that the value from the MPP, i.e. 5.985 GJ/t ( = 1.663 MWh/t), had been reduced by the electricity demand of the EAF. Given that the EAF has an energy demand of approximately 0.6 MWh/t (see plot below), this probably adds up fine.
• Consequently, the values reported by MPP for the combined route must be assuming some substantial remaining electricity demand for the direct reduction furnace.
• From what I read, there seems to be general agreement that the electricity needed for operation other than heat is very low (typically 0.1–0.2 MWh/t). The only questions is how much heat is needed and whether this heat is supplied via electricity.
• The lack of clarity about the electricity required for heating may stem from ambiguity concerning the reporting of the different energy carriers between sources. Natural gas is often reported as a carbon source needed for steelmaking. Hydrogen is differentiated between heat and reduction agent by some sources, but not by all.

Suggestion

First, I'd be interested to hear your feedback.

After that I would suggest to update the data and assume a slightly lower value for the electricity consumption of the direct reduction furnace.

Generally, if you find this kind of analysis helpful: one specific aim of the POSTED framework is to identify and resolve such issues. Let me know if you're interested to collaborate on this more.

References

• Alexandra Devlin and Aidong Yang. Regional supply chains for decarbonising steel: Energy efficiency and green premium mitigation. Energy Conversion and Management, 254:115268, Feb 2022. https://doi.org/10.1016/j.enconman.2022.115268
• Eric Jacobasch, Gregor Herz, Christopher Rix, Nils Müller, Erik Reichelt, Matthias Jahn, and Alexander Michaelis. Economic evaluation of low-carbon steelmaking via coupling of electrolysis and direct reduction. Journal of Cleaner Production, 328:129502, Dec 2021. https://doi.org/10.1016/j.jclepro.2021.129502
• Alexander Otto, Martin Robinius, Thomas Grube, Sebastian Schiebahn, Aaron Praktiknjo, and Detlef Stolten. Power-to-Steel: Reducing CO2 through the Integration of Renewable Energy and Hydrogen into the German Steel Industry. Energies, 10(4):451, Apr 2017. https://doi.org/10.3390/en10040451
• Valentin Vogl, Max Åhman, and Lars J. Nilsson. Assessment of hydrogen direct reduction for fossil-free steelmaking. Journal of Cleaner Production, 203:736–745, Dec 2018. https://doi.org/10.1016/j.jclepro.2018.08.279

Bibliographic info also available here.