Abstract: 3D printing, or additive manufacturing, is transforming electrical engineering by driving advancements in sustainable energy systems, urban infrastructure, and industrial innovation. This paper explores its applications in fabricating energy-efficient components, such as photovoltaics, wind turbine parts, and energy storage systems, as well as its role in advanced prototyping and smart grid technologies. The adoption of advanced materials, including conductive polymers and biodegradable composites, supports the development of renewable energy systems and customized solutions for urban and industrial applications. By reducing material waste, lowering production costs, and accelerating innovation cycles, 3D printing fosters sustainable manufacturing practices and resilient infrastructure development. Challenges such as material compatibility, scalability, and costs are discussed, alongside emerging technologies like artificial intelligence (AI) and the Internet of Things (IoT), which enhance optimization and broaden applications. This study highlights the critical role of 3D printing in advancing sustainable energy, urban development, and industrial modernization.