Green technology is a promising economic engine, which can balance the industrial development and the protection of environment. The core of all the green technologies is energy because the energy demand increases continuously as time goes by. However, the increase of energy supply is difficult because existing nuclear power plants and thermal power plants have either high risk or cause environmental pollution. Therefore, new renewable energies have been sought to solve these problems. The typical renewable energy, solar power and wind power, may be a source of environmentally friendly energy without the emission of pollutants, but it has the limitation because of unstable output. In other words, the solar and wind power energies cannot ensure a stable constant output, and are difficult to construct collaboration network with the existing power. Therefore, there has been strong demand for an energy source such as fuel cells as well as an energy storage system (ESS), which can store the excess energy at non-peak time of power and supply power at the required peak time. In short, it is necessary to develop the energy sources and energy storage technologies to solve the energy shortage and pollution problems of the next generation.