Renewable energy drives growing round steel demand: wind turbines use large-diameter 42CrMo4 rounds for main shafts (withstanding 100+ ton loads), while solar panel frames use 304 stainless rounds (corrosion resistance). Hydropower requires 350 MPa+ rounds for turbine components. Global demand from renewables is projected to grow 12-15% annually through 2030, outpacing traditional construction. High-strength, corrosion-resistant grades are prioritized, with manufacturers investing in specialty production lines to meet specifications for fatigue resistance and low-temperature toughness.