Storage technology is now available for different stages of development, varying project scales, and for meeting both short and long-term energy storage needs. Short-term storage technologies can compensate for output fluctuations that only last a few hours, whereas longer term or seasonal storage technologies can bridge the gap over several weeks. There is no “one-size-fits-all” technology for storage. Along the entire supply and demand chain, different storage technologies are required – from second reserve for frequency stability to seasonal storage for several months. A cascade of different storage technologies is required to support: the local integration of power generation from variable renewable energy (VRE) in distribution networks; the grid infrastructure to balance VRE power generation; and self-generation and self-consumption of VRE by customers.
Short-term storage options include batteries, flywheels, compressed air power plants and pump storage power stations with high efficiency factors. The latter is also used for long-term storage. Seasonal storage technologies include hydro pumped storage and the production of hydrogen or renewable methane.
From the REN21 report “Renewables Global Futures Report: Great debates towards 100% renewable energy”.