Blue energy—renewable power derived from the kinetic and potential forces of water—has become a key pathway for building sustainable and low-carbon energy systems. This review synthesizes global progress in hydropower, ocean energy, and hybrid offshore technologies, highlighting rapidly advancing wave-energy devices and triboelectric nanogenerators (TENGs) for blue energy. While hydropower is technologically mature, ocean-based energy systems are expanding due to vast resource potential and accelerating technological innovation. The review identifies promising designs for efficient wave-energy harvesting alongside remaining engineering challenges related to durability, cost, and large-scale deployment. Together, these insights provide a roadmap for advancing water-derived renewable energy to support global decarbonization.

Researchers at the Korea Institute of Energy Research (KIER), led by Dr. Hookyung Lee, have developed an electrified heat treatment technology that replaces fossil fuels with electricity in the metal heat treatment process used in galvanized steel-strip production for automobiles and household appliances. The technology is expected to be broadly applicable across energy-intensive industries such as steelmaking, supporting decarbonization of industrial processes.

Harnessing solar energy to enhance the rechargeable zinc–air batteries (RZABs) performance is a promising avenue toward sustainable energy storage and conversion. Simultaneously enhancing light-absorption capacity and carrier separation efficiency in nanomaterials, as well as improving electrical conductivity and configuration for electrocatalysis, presents a formidable challenge due to inherent trade-offs and interdependencies. Here, we have developed a Janus dual-atom catalyst (JDAC) with bifunctional centers for efficient charge separation and electrocatalytic performance through a bipolar doping strategy. The in situ X-ray absorption near-edge structure and Raman spectroscopy analyses demonstrated that the Ni and Fe centers in JDAC not only function as effective sites for oxygen evolution reaction and oxygen reduction reaction, respectively, but also serve as efficient hole and electron enrichment sites, effectively suppressing photoelectron recombination while enhancing photocurrent generation. As a result, the assembled JDAC-based light-assisted RZABs exhibited extraordinary stability at large current densities. This work delivers pivotal insight to design Janus dual-atom catalysts that efficiently convert solar energy into electric and chemical energy.