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Hydraulic Battery (micro PHS)

Hydraulic storage solution coupled with solar panels, providing clean energy 24/7 to rural and isolated areas

March 2022
Gallery Hydraulic Battery (micro PHS) 1
Gallery Hydraulic Battery (micro PHS) 1


STEPSol has designed an innovative hydraulic storage solution based on the principle of Pumped-storage Hydropower (PSH), or STEP in french, but in reduced dimensions (less than 1MW), outside watercourses and coupled with a solar plant: the Hydraulic Battery. During the day, solar panels power a village but also a pump which brings the water from a lower tank to an upper tank (declivity of +50 meters). When night falls, or when the electrical demand is too important, water goes down and activates a turbine, which will produce electricity and compensate for the lack of solar energy. This innovative but yet rustic solution is accessible for local users who can assure its maintenance and participate in civil works STEPSol focuses its offer on energy flexibility and the permanent adaptation of its micro PHS to the specific conditions of each site. Thanks to its competitive price, low tech conception and long lifespan, the Hydraulic Battery is a great alternative for off grid zones.

  • /
Label Date March 25, 2022
From France
Maturity stage Small scale commercialization
Looking For Network, New clients, Visibility, Funding, Partners

The environmental benefits

  • Electricity generation 24/7 thanks to solar production and water storage
  • A PHS totally reduced in size: Power up to 1MW and basins up to 10.000m3
  • Lifespan of more than 25 years + Up to 70% of efficiency
  • 0% Water lost, 0% chemical pollution risks
  • Using a Diesel production : 0,35lt of fuel to produce 1kWh of electricity // Using STEPSol's solution: no fuel consumption

The Financial benefits

  • Payback period of the investment between 4 to 10 years
  • Cheaper than diesel solutions LCOE : 150-250$/MWh (vs. diesel LCOE : 300-600$/MWh, source Lazard)
  • A resilient and improved electrical service (fuel independent) with positive impact on local economic activities

Activity Region

  • /


France, Switzerland,

South america



French Polynesia,

  • Headquarters
  • Activity

Company Profile


STEPSol proposes an innovative storage solution, sustainable and competitive for isolated areas, the Hydraulic Battery!

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Headquarters 20217 Nonza, France

Networking Partner


ADEME - The French Agency for Ecological Transition- is a public agency under the joint authority of the Ministry for an Ecological Transition and the Ministry for Higher Education, Research and Innovation.

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The information set out above, is solely for the purposes of information and the Solar Impulse Foundation does not provide any guarantee as to its authenticity, completeness or accuracy. This information does not constitute investment advice or a recommendation to buy into, transact or to enter into any agreement with any of the parties or persons mentioned above. Potential investors or interested parties are solely responsible for their investment or business decisions and for performing any due diligence required by the circumstances. The innovator STEPSol has asserted ownership of the intellectual property rights for images, videos, and content showcased above, affirming full and unrestricted usage rights, and has provided explicit permission for the Solar Impulse Foundation to publish such information designated as "public" in the application form.