Steel is of great significance to people's daily life. The application of iron and steel products has observably promoted the progress of human civilization, science and technology, and the development of productive forces. In recent years, the steel production and consumption have generally maintained at high level. In 2022, the total crude steel production capacity in world reaches 1878.5 million tons. China is responsible for more than 50 % of the worldwide steel production, and the steel yield exceeds to 1013.0 million tons. Regardless of rapid development of material science and technology, the basic supporting role and core status of iron and steel materials still cannot be shaken. It is foreseeable that the supply and demand of steel will still maintain at a high level in the future for a long time. However, the energy-intensive iron and steel industry (ISI) consumes considerable fossil fuels. The energy consumption of ISI is equivalent to 650 million tons of standard coal, accounting for 15.1 % of the total energy consumption in China. Besides, the exploit of energy and resources in ISI lead to the greenhouse gas (GHG) emissions of almost 2.11 billion tons (18.3 % of domestic industrial emissions). The ISI meets serious challenges in ecological environment and energy-resource security.

To cope with the increasing serious environmental problems and resource and energy depletion, China has announced carbon peak and carbon neutrality goals in September 2020. As the key foundation of socio-economic development in China, it is imperative and important for ISI to undertake the task of energy conservation and emission reduction. There are two main routes to produce steel, which are summarize as the short-process and long-process. The short-process takes electric arc furnace (EAF) steelmaking as the core, while the long-process depends on blast furnace-basic oxygen furnace (BF-BOF) steelmaking. Compared to the energy consumption of 600–700kgce and GHG emissions of 2000–2400 kg per ton of steel in BF-BOF route, the energy consumption and GHG emissions are only 350 kgce/t and 500–700 kg/t in EAF route. Therefore, during the 14th Five-Year-Plan of China, the environmentally friendly and energy-saving EAF steelmaking process is reemphasized and strongly promoted.

Most of the steel plants abroad are widely exploiting EAF steelmaking method. In contrast, the share of EAF route in China is merely about 10 %. The reason mainly derives from extensive consumption of scrap resources and electricity. EAF steelmaking processes take scrap as main iron-bearing charge. The scrap supply is just 88.3 Mt (10 % of the total crude steel production). The utilization rate of scrap (the fraction of collected and reused scrap to the total social available scrap resources) is 10.7 %, which is significantly lower than that in US (75 %), EU (58 %), and Japan (35 %). In addition, the electricity is the dominant contributor of inputting energy in EAF steelmaking processes, with the consumption of about 320–580 kWh/t. Which brings extensive cost considering the fact that massive steel yield and expensive industry electricity price of 0.112 $/kWh. The further development of EAF route in China is limited by the shortage of scrap supply and reserve and energy cost. Nowadays, with the upgrading of steel products, the comprehensive utilization of steel scrap resources has been paid more attention, and the problems brought by the scarcity of scrap will gradually ease. The present EAF steelmaking process in China still relies on indispensable hot metal with scrap to complete the steel production. As for the direct reduced iron (DRI), it is almost not considered due to its lower output and smaller consumption compared to hot metal and scrap. The challenges driven by energy, especially electricity, have not been well solved in EAF steelmaking processes. Besides, the power supply schemes in China mainly depends on thermal power, and clean energy generation scale is relatively small. Except for high cost, the environmental problems caused by power generation gradually aggravate.

Renewable energy is a good solution to the energy shortage. Renewable energy power generation is an effective and the most widely used utilization way with mature technologies and easy accessibility. In 2022, the total installed gross capacity in renewable energy is 1.213 billion kW, which have historically surpassed that of 1.12 billion kW in coal power. Wind energy serves as one of typical clean, inexhaustible, renewable energy sources. The Chinese wind energy generation capacity reached 365 GW by the end of 2022. The average power density of annual wind energy of two height layers are 193.1 and 227.4 W/m2, respectively. Besides, in coastal areas, northeast regions, and northwest high-altitude areas, the average wind speed is more than 7 m/s, which means abundant available wind energy. Further development and utilization of wind energy is of great significance to energy structure adjustment and environmental protection.

Wind energy integration is a key step for industrial development and application of wind energy. Many scholars are dedicated to the analysis of various applications of wind energy integrations. In case of the traditional ISI, there are also some reports about wind energy integration systems.

Renewable power sources can be effectively integrated into the EAF steelmaking system to provide a pathway to green the steel industry and reduce environmental and health risks. EAFs rely on electricity as an energy source to heat the EAF and produce liquid steel from scrap steel. They work in short and high-power bursts and then spend a long time idle for power transfer and liquid steel testing. These patterns are suitable for utilizing renewable power sources (solar, wind, hydro, etc.) to stabilize and lower the cost of power supply for EAFs, thereby reducing their CO2 footprint. Every ton of steel produced from EAFs produces 700–900 kg of CO2, so the direct impact of EAFs on CO2 is huge. Changes to the EAF operations should reduce CO2 emissions and align steelmaking processes with climate targets.

This change will drive the transition toward a sustainable and circular economy. One of the main challenges is the high variability and intermittence of main renewable energy sources (solar, wind, etc.). Thus, it is essential to introduce energy storage systems and smart grid technologies to achieve a well-balanced flow of energy from the grid to the EAF. Introducing a well-balanced power supply system can help identify the potential of batteries, smart grids, and hydrogen-related technologies to facilitate the transition to EAF systems and minimize CO2 emissions. Specifically, the use of smart grid infrastructure, operational scheduling, and flexibility allows EAFs to operate steadily despite variability in solar- and wind-based power. This way, the embedded hidden carbon and environmental impacts in a closed-loop system can be realized and minimized to achieve low CO2 emission levels as soon as possible.

Additionally, direct steelmaking issues and potential integration of solar- and wind-based EAF technologies will enable further innovation and integration with for example hydrogen reduction processes and waste heat recovery (Fig. 2). Such hybrid systems can improve overall energy efficiency, reduce CO2 emissions, and help to reduce the steel-making sector´s CO2 footprint further. Specifically, without such renewable-energy-driven EAF steelmaking, their potential to operate on 100% renewable electricity will be hindered, severely affecting the environmental achievement of the steel industry. This transformation will thus catalyze the transformation of CO2-intensive industries to more environmentally friendly and sustainable ones. Integration of renewable energies such as solar- and wind-based EAF technology can also stimulate innovation through a full integrated EAF system with hydrogen (H2) and other biogas, residual waste gas, or solid fuel-based steel production. Such systems can improve the overall energy efficiency and reduce CO2 emissions, as seen in Fig. 2. Further innovation in this area is urgent because of the ambitious climate targets for the global steel sector (IEA 2018). IoT-based tools can help control energy efficiency gains from the grid to the EAF, include solar- and wind-based EAF technology, and other biogas, residual waste gas, or solid fuel-based steel production (Li, et al., 2020).

These issues can be overcome by combining tools and methodologies (Morris, et al., 2021), including energy management, sensing and controls, and so forth, to facilitate discussions and data interchange. This will require a holistic and transparent vision to achieve CO2-free steel plants by 2050. Integration of renewable powers (solar and wind) with EAF processes will enable new, smart, low-carbon systems like hydrogen-based EAFs. Renewable electricity and renewable hydrogen production can be connected in EAF plants to directly substitute fossil systems during the CO2-intensive steelmaking process. Such smart, low-carbon, and renewable-energy-driven EAF processes can revolutionize the entire steelmaking paradigm by eliminating CO2 emissions (Zhang, et al., 2019).

However, it is yet unclear how renewable energy integration with EAF would best facilitate such smart CO2-free EAF technologies. Such green, electric renewable EAF plants will be cornerstone of the new, green smart steel plant paradigm by increasing energy efficiency and reducing the CO2 footprint from the entire steel industry. This will reduce the entire steel industry´s CO2 footprint, but this will put challenges on integrating residual waste gas or solid fuel-based steelmaking. Renewable-energy-driven EAF steelmaking would force a step-change in energy management - process in relation to the grid and process (Zhang, et al., 2019).

References

Li, X., Wang, J., & Zhang, H. (2020). Energy storage and smart grid solutions for renewable energy integration in electric arc furnace steelmaking. Journal of Cleaner Production, 246, 118982.

Morris, J., Patel, M., & Brown, T. (2021). Renewable energy integration in electric arc furnace steel production: Opportunities and challenges. Renewable and Sustainable Energy Reviews, 143, 110890.

Zhang, H., Chen, Y., & Wang, J. (2019). Hybrid renewable energy systems for sustainable steelmaking: Integration with electric arc furnaces. Ironmaking & Steelmaking, 46(5), 426–434.

Avoid wind farms:

Large-scale wind farms may be intensifying regional warming by extracting kinetic energy from the atmosphere, disrupting natural thermodynamic balance. Findings suggest that for every 1 MW of electricity, up to 60 MW of thermal impact may be introduced into the climate system leading in a wind distribution COLLAPSE

ARTICLE: https://www.researchgate.net/publication/393460831_Wind_Energy_Extraction_and_Atmospheric_Disturbance_Local_Warming_Cooling_and_Gradient_Amplification

Consequences already observed:

– Reduced rainfall and increased heatwaves

– Rising sea temperatures

– Collapse of agricultural and tourism patterns

– Potential inhabitability of large southern regions