Energy storage - Wikipedia

Energy Storage Overview

  • Definition: Energy storage captures energy produced at one time for use later, balancing demand and production.

  • Storage Devices: Common devices include accumulators and batteries.

Types of Energy

  • Various forms include:

    • Radiation

    • Chemical

    • Gravitational potential

    • Electrical potential

    • Electricity

    • Elevated temperature

    • Latent heat

    • Kinetic

Mechanisms of Energy Storage

  • Involves converting energy from difficult-to-store forms to more manageable ones.

Examples of Energy Storage

  • Llyn Stwlan Dam: Part of Wales' Ffestiniog Pumped-Storage Scheme with four turbines generating 360 MW of electricity.

  • Short-term vs Long-term Storage: Different technologies offer varying durations of energy storage.

    • Bulk energy storage is mainly provided by hydroelectric dams, including both conventional and pumped varieties.

    • Grid energy storage consists of methods for large-scale energy storage within electrical grids.

Common Examples

  • Rechargeable Batteries: Store chemical energy convertible to electricity.

  • Hydroelectric Dams: Utilize gravitational potential energy stored in reservoirs.

  • Ice Storage Tanks: Freeze ice at night with cheaper energy to meet daytime cooling demands.

  • Fossil Fuels: Includes materials like coal and gasoline that store ancient solar energy.

  • Food: Also a form of energy stored chemically.

Historical Context

  • In the 20th century, fossil fuels dominated electricity generation.

  • During low power demand, less fuel was burned.

  • Hydropower: Mechanical energy storage method adopted for over a century.

Innovations and Concerns

  • Growing concerns over air pollution, energy imports, and global warming spurred renewable energy development.

  • Intermittent Energy Sources: Wind and solar power generation is variable, necessitating storage solutions.

  • BloombergNEF Forecast (2023): Anticipated 27% annual growth in energy storage deployments until 2030.

Off-Grid Usage

  • Off-grid electrical use moved from niche to widespread in the 21st century; portable solar panels are common in rural areas.

Energy Storage Types and Methods

  1. Mechanical Storage

    • Spring storage

    • Compressed-air energy storage (CAES)

    • Flywheel energy storage

    • Pumped-storage hydroelectricity

  2. Thermal Storage

    • Brick storage heaters

    • Ice storage air conditioning

    • Seasonal thermal energy storage

  3. Chemical Storage

    • Biofuels

    • Hydrogen and various power-to-gas methods.

  4. Electrochemical Storage

    • Rechargeable Battery Types:

      • Lead-Acid

      • Nickel-Cadmium (NiCd)

      • Nickel-Metal Hydride (NiMH)

      • Lithium-Ion

      • Aluminum-Sulfur

  5. Supercapacitors

    • High power capabilities; used in buses and cranes.

  6. Emerging Technologies

    • Carnot Batteries: Convert electricity to heat and back to electricity.

    • New storage materials and chemical processes.

Applications of Energy Storage

Mechanical

  • Examples include gravitational methods and pumped hydro systems that leverage potential energy for electricity generation.

Grid Energy Storage

  • Pumped-Storage: Largest global storage capacity, offering flexibility during peak demand.

  • Compressed Air Systems: Store surplus renewable energy for later use.

  • Flywheels: Store energy as rotational kinetic energy, with significant lifecycle and maintenance advantages.

Economic Considerations

  • Cost Factors: Economic viability of energy storage is influenced by storage capacity, technology type, and market conditions.

  • Energy Storage on Energy Invested (ESOI): A measure of energy efficiency of storage technologies.

Future Outlook

  • Progress being made in renewables, electric vehicles, and home energy storage systems aspirations.

  • Increasing role of energy storage in the future energy landscape as climate realities prompt shifts in energy strategy.