Thermoelectric (TE) systems are solid-state energy converters that can directly convert waste heat into electricity or electrical power into cooling and heating. These materials can compete with fluid-based systems like air conditioners and heat pumps, but their widespread use requires improving intrinsic energy conversion efficiency and system architecture. TE devices use electrons as the working fluid, and their performance is governed by the Peltier effect and the Seebeck effect. Despite their potential, TE systems have been limited by low efficiency and high costs. Recent advancements in material science, such as nanotechnology, have shown promise in improving ZT (a figure of merit) and reducing parasitic losses. These improvements could enable broader applications in cooling, heating, and power generation, particularly in vehicles, industrial processes, and remote locations. Higher ZT values could lead to zero-CO₂ emissions in air conditioning and heating systems and reduce fuel consumption in power generation. The future of TE technology looks promising, with the potential to address sustainability issues and reduce environmental impact.Thermoelectric (TE) systems are solid-state energy converters that can directly convert waste heat into electricity or electrical power into cooling and heating. These materials can compete with fluid-based systems like air conditioners and heat pumps, but their widespread use requires improving intrinsic energy conversion efficiency and system architecture. TE devices use electrons as the working fluid, and their performance is governed by the Peltier effect and the Seebeck effect. Despite their potential, TE systems have been limited by low efficiency and high costs. Recent advancements in material science, such as nanotechnology, have shown promise in improving ZT (a figure of merit) and reducing parasitic losses. These improvements could enable broader applications in cooling, heating, and power generation, particularly in vehicles, industrial processes, and remote locations. Higher ZT values could lead to zero-CO₂ emissions in air conditioning and heating systems and reduce fuel consumption in power generation. The future of TE technology looks promising, with the potential to address sustainability issues and reduce environmental impact.