Gravity Storage

A new solution for large scale energy storage

The worldwide rapid construction of fluctuating renewable energy sources, such as wind and solar energy, has created an increasing demand for storing large quantities of energy. To sustain an uninterrupted supply of energy in a grid system dominated by renewable energy sources, there must be substantially larger storage capabilities than available today to cover long periods of little or no wind, and reduced periods of sunshine.

Simple, clever and durable: The technical concept of Gravity Storage uses the gravitational power of a huge mass of rock and reaches a storage capacity between 1 and 10 GWh.

Learn more about the unrivaled economic concept, which will to be one of the cheapest ways to store huge amounts of electricity and turn renewable into a reliable 24/7-source of energy.

Heindl Energy is a German technology company, focused solely on the development of Gravity Storage. Get to know us and our partners.

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About Gravity Storage

Gravity Storage is a concept with which unprecedentedly large quantities of power can be stored for a long time of 6-14 hours, and can be made available again. The fundamental principle is based on the hydraulic lifting of a large rock mass. Using electrical pumps, as already used today in pumped storage power plants, water is pumped beneath a movable rock piston, thereby lifting the rock mass. During times of insufficient generation of renewable power, the water which is under high pressure from the rock mass, is routed to a turbine, as in conventional hydroelectric plants, and generates electricity using a generator.

The capacity of energy storage reaches 8 GWh or more, comparable to large Pumped Hydro Storage. 

The rock piston should have a diameter of at least 100 meters in order to be competitive with pumped storage power plants. The real costs will vary for each site. But we calculate with costs of about 200 USD/kWh capacity at a size of 250-meter diameter.

Advantages of Gravity Storage


  • Gravity Storage is economically superior to all other energy storage solutions: Low investment costs of approx. 200 USD/kWh storage capacity (for an 8 GWh solution, based on German prices)
  • Low running costs of less than 1% of capex per year


  • Gravity Storage requires no elevation difference (suitable for flat terrains, unlike pumped hydro storage)
  • It can be easily integrated into any high voltage transmission grid
  • More than 40% of the continental surface is basically suitable for Gravity Storage


  • Minimal raw material requirements (“just rock and water”)
  • Requires much less water than pumped hydro storage
  • Small land footprint per kWh
  • No chemicals required
  • Long service time beyond 60 year


  • The system buffers fluctuating energy on a GWh-scale and maximizes use of excess energy by enabling it to be used during periods of low generation
  • High round-trip energy efficiency of 80% or more
  • Provides a variety of system services: dispatching, black start capability, rotating masses
  • Fast and steep load ramping comparable with that of any modern pumped hydro system
  • Discharging time can be tailored to each operator’s individual needs

About Heindl Energy

Heindl Energy´s mission is to transform the world’s energy storage landscape, paving the way towards a sustainable, clean power supply.

By solving the energy storage challenge in this way, we aim to support the development of reliable power supply systems that are 100% based on production from renewable sources.

The concept of Gravity Storage was invented by Professor Eduard Heindl and has since then been continually developed by the Stuttgart-based company Heindl Energy GmbH, supported by a team of civil engineering, geology, mining and geophysics specialists.

Meet us at Energy Storage North America, Nov 5-7 in San Diego, CA; Booth 733 Make an appointment now: