A wide array of nanotechnologies can be used to improve the efficiency of energy harvest from the Sun and the wind, and the efficiency of energy storage in secondary batteries, for use in smart grid and transportation applications. High-quality nanostructured copper indium gallium selenide thin films help produce high-efficiency photovoltaic modules. Various nanotechnologies are utilized to improve the efficiency of power-generating wind turbines, including nanoparticle-containing lubricants that reduce the friction generated from the rotation of the turbines, nanocoatings for de-icing and self-cleaning technologies, and advanced nanocomposites that provide lighter and stronger wind blades. A number of nanotechnologies can be beneficial in advanced high-capacity secondary batteries for smart grid and transportation applications. These technologies include nanostructured carbon-nanotube–based and silicon-nanowire–based electrodes with ultrahigh surface areas, as well as nanoengineered β-alumina ceramic electrolytes with well-controlled grains, grain boundaries, and crystal orientation, which are used to boost the energy and power densities in secondary batteries such as lithium-ion, sodium-sulfur, flow, and dry cell batteries.