European Commission
JRC Smart Electricity Systems

Technology Landscape

Overview of the Energy Storage Technology Landscape

The energy storage technology landscape is rapidly evolving, driven by the increasing need to integrate renewable energy sources into the grid and achieve sustainability goals. The adoption rate of energy storage technologies is accelerating, with significant advancements in battery storage, pumped hydro, and emerging technologies like hydrogen storage and thermal storage.

Energy storage systems are crucial for balancing supply and demand, ensuring grid stability, and enhancing energy efficiency. The penetration rate of these technologies varies by region, with China, the US, and Europe collectively representing the majority of global installations. 

As renewable energy sources like wind and solar become more prevalent, the role of energy storage in maintaining a reliable and resilient energy supply becomes increasingly important.

Chemical Storage

Chemical storage involves converting electricity into chemical energy, which can be stored and later converted back into electricity or used as a fuel. A key sub technology is Power to Gas (H2). This process converts surplus electricity into hydrogen via electrolysis. The hydrogen can be stored and used as a fuel or reconverted into electricity using fuel cells. This method is suitable for long-term storage and helps balance seasonal variations in renewable energy production.

Electrochemical Storage

Electrochemical storage includes various types of batteries that store energy through chemical reactions. 

Key sub technologies are:

  • Lithium-ion Batteries: Widely used for their high energy density and efficiency, making them ideal for portable electronics and electric vehicles.
  • Redox Flow Batteries (Vanadium): Utilize vanadium ions in different oxidation states to store energy, offering scalability and long cycle life, suitable for large-scale energy storage.
  • Iron Air Battery: Uses iron and air to store energy, known for its potential low cost and high energy density.
  • Sodium Sulphur Batteries: Operate at high temperatures and offer high energy density, typically used for grid storage.
  • Lead Acid Batteries: One of the oldest types of rechargeable batteries, commonly used in automotive and backup power applications.
  • Lithium-Metal-Polymer Batteries: Feature a solid polymer electrolyte, offering safety and energy density advantages.
  • Lithium-titanate Battery (LTO): Known for fast charging and long cycle life, used in applications requiring high power.
  • Sodium Nickel Chloride Batteries: Also known as ZEBRA batteries, they operate at high temperatures and are used in industrial and grid applications.

Mechanical Storage

Mechanical storage utilizes physical systems to store energy. Key sub technologies are:

  • Compressed Air Energy Storage (CAES): Stores energy by compressing air in underground caverns or tanks, which is later released to generate electricity.
  • Pumped Hydro Storage (PHS): The most established method, it stores energy by moving water between reservoirs at different elevations, providing large-scale storage capacity.
  • Flywheel: Stores energy in the form of rotational kinetic energy, offering rapid response and high power output, suitable for stabilizing grid frequency.

Thermal Storage

Thermal storage captures and stores heat for later use. Key sub technologies are:

  • Molten Salts: Used in concentrated solar power plants, molten salts can store heat at high temperatures and release it to generate electricity when needed.
  • Sensible Thermal Energy Storage (STES): Involves storing thermal energy in materials like water or rocks, which can be used for heating or cooling applications.