Innovative Gravity Energy Storage Systems

Aug 29, 2024

Lecture Notes on Gravity Energy Storage and Re-Energize's R19 System

Introduction to Pump Storage Hydropower

  • Traditional pump storage hydro power stations act as gravity batteries.
  • Use water from an upper reservoir to store and release energy by spinning turbines.
  • Limitations include lack of density compared to materials like concrete or lead.

R-Energize's Innovative Approach

  • R19 Breakthrough: Combines flexibility of water and high density of other materials.
  • Concept resembles mechanics of cuckoo clocks, storing potential energy via lifted weight.
  • Closed loop hydro power systems utilize this principle.
    • Water flows between reservoirs to generate energy during high demand.
    • Water is pumped back up during excess energy periods.

Limitations of Traditional Pump Storage

  • Geographical and Cost Limitations: Conventional pump storage systems are expensive and geographically constrained.
  • Example: Swiss Alps pump storage facility - 900 MW, 20,000 MWh capacity, over 2,000 m above sea level.

R-Energize's Waterless Hydro Energy System

  • Operates effectively on small hills instead of high mountains.
  • Uses a dense slurry instead of water, allowing for smaller reservoirs and less height difference.
  • Energy Density: The slurry stores 2.5 times the energy using the same volume.

Details of R19 System

  • Fluid Composition: Ultra-fine powder of solid particles mixed with a surfactant.
  • Viscosity Management: The slurry has a viscosity of 20 centipoise (cp); manageable flow characteristics.
    • Pipes need to be 25-30% thicker to account for increased viscosity.

Challenges and Considerations

  • Temperature Sensitivity: High-density fluids are sensitive to temperature changes affecting viscosity.
  • Need for temperature control using heating elements or excess turbine heat.
  • Separation of Components: Water and solids in the slurry could separate over time; requires finely milled particles and constant movement.

Demonstrations and Future Plans

  • Demonstration Success: First demo showed R19 achieving twice the power output of water at the same elevation.
  • Upcoming construction of a 500 kW demonstrator in Plymouth, England.
    • Expected operation to help decarbonize mining operations.
  • Plans for 10-50 MW grid projects and a goal for 100 MW ratings by 2030.
    • Application includes a partnership with apple farmers for a microgrid in South Africa.

Benefits of R-Energize's System

  1. Increased Energy Density: Faster and easier construction of systems.
  2. Reduced Environmental Footprint: Smaller reservoirs, less recycling, and minimal use of rare earth metals.
  3. Established Technology Foundation: Builds upon traditional pump storage systems, reducing R&D costs.
  4. Cost Effectiveness: Projected levelized storage cost of $150/MWh vs. $25/MWh for lithium-ion batteries.

Conclusion

  • R-Energize's system offers a promising alternative to conventional energy storage methods.
  • Questions remain about long-term viability and operational challenges.
  • Ongoing research and demonstrations will determine practical success.