Clean energy is a combination of energy efficiency and clean energy supply options like highly efficient combined heat and power as well as renewable energy sources. By identifying, designing and implementing clean energy technology solutions, we are delivering important environmental and economic benefits. Electricity from renewable resources such as solar, geothermal, and wind technologies generally do not contribute to climate change or local air pollution since no fuels are combusted in these processes. However, wind or solar energy sources have a variable electricity output and cannot be relied on directly in covering the energy demand. They tend to produce energy when it is not needed or the generation output is insufficient. Therefore, renewable energy sources have limited contribution to power generation.
Energy storage technologies are a solution to this problem, because they can be integrated in the power system structure with different renewable energy sources. These technologies can maximize the contribution of renewable energy, promoting efficient use of the same, facilitating the equilibrium between generation and demand, reducing emissions of greenhouse gases, reducing network connection costs and improving operation and control of the power system. The most relevant parameters that define these storage devices are storage capacity, energy available and discharge time.