Gravity Battery Calculator: Convert Mass & Height to kWh
Enter raised mass, vertical height, efficiency and discharge duration to estimate delivered kWh/MWh and average kW/MW from a gravity-storage concept.
Estimate gravity-storage energy and power
Enter mass, height, efficiency and duration to estimate delivered kWh/MWh and average kW/MW. This is a first-pass physics estimate, not a cost, safety or constructability decision.
Advanced assumptionsEarth gravity by default
Gravity defaults to 9.80665 m/s² and can be adjusted above. This potential-energy estimate does not size motors, generators, cables, brakes, structural loads, cycle life or site civil works.
How to use this gravity battery calculator
Start with the mass you can raise, the usable vertical height, an efficiency assumption and the discharge duration. The calculator returns gross potential energy, delivered kWh or MWh after losses, and average kW or MW over the selected duration. Energy answers how much electricity can be delivered; power answers how quickly it must be delivered.
Gravity storage is direct potential energy: lifting a mass creates a height difference, while lowering it through a motor-generator returns part of that energy as electricity.
What the result means in practice
The same energy can come from more mass with less height, or less mass with more height. Neither result alone establishes a workable project: energy scale, machine power and the physical path for the moving mass must all work together.
- Raised mass
- More moving mass increases stored energy in a straight line. Tonnes are convenient for first-pass civil and mechanical scale checks.
- Vertical height
- Each additional metre adds the same amount of potential energy. Deep shafts and tall structures are the key site constraint.
- Round-trip efficiency
- Motors, generators, gearboxes, power electronics and mechanical losses mean a real system returns less energy than the ideal potential.
- Discharge duration
- Duration does not change stored energy. It sets the average power the system must deliver while the mass descends.
Worked gravity-storage scales
This first comparison holds raised mass at 1,000 tonnes and shows how additional vertical height changes the potential-energy result.
| Vertical height | Ideal potential energy | Delivered energy at 80% efficiency |
|---|---|---|
| 100 m | 272 kWh | 218 kWh |
| 300 m | 817 kWh | 654 kWh |
| 500 m | 1.36 MWh | 1.09 MWh |
Illustrative MWh-scale physics at 80% efficiency — not proposed system designs. Each example has the same 500,000 tonne-metre mass-height product.
| Raised mass | Vertical height | Delivered energy at 80% efficiency |
|---|---|---|
| 1,000 t | 500 m | 1.09 MWh |
| 2,500 t | 200 m | 1.09 MWh |
| 5,000 t | 100 m | 1.09 MWh |
Before treating a result as a project
Use the calculated energy as a screening number, then check the practical constraints that determine whether a gravity-storage concept can be built, operated and maintained safely.
- Moving-mass path
- Confirm the travel distance, guidance, clearances, access and recovery path for the raised mass.
- Structural and civil loads
- Evaluate foundations, shafts, towers, anchors and the loads transferred into the surrounding structure or ground.
- Machine power
- Size motors, generators, gearboxes, brakes, drives and cables for the intended discharge power, not only the stored energy.
- Loss assumptions
- Validate conversion, friction, standby and auxiliary losses instead of relying on an ideal potential-energy number.
- Duty cycle
- Test charging time, discharge schedule, cycling frequency and maintenance windows against the operating profile.
- Safety controls
- Define containment, overspeed protection, braking, inspection, access control and emergency procedures for moving equipment.
- Project economics
- Compare site preparation, equipment, grid connection, operations and maintenance against the value the storage service can create.
FAQ
How do you calculate gravity battery energy?
Use E = m × g × h, where m is mass in kilograms, g is gravitational acceleration at about 9.81 m/s², and h is vertical height in metres. Divide joules by 3,600,000 to convert to kWh, then apply system efficiency for delivered energy.
How much energy does one tonne lifted by one metre store?
At ideal efficiency, one tonne raised by one metre stores about 0.002724 kWh, or 2.724 Wh. Large gravity systems therefore need a great deal of mass, vertical height, or both.
What is the difference between energy and power in gravity storage?
Mass and height determine stored energy. Generator capacity and discharge duration determine power. The same stored energy can be released quickly at high power or more slowly at lower power.
Does this tool estimate real project cost or feasibility?
No. It is a first-pass physics estimate. Real projects must account for mechanical equipment, structural loads, friction, generator and motor limits, cable runs, civil works, safety systems and site economics.
How much energy is delivered per tonne per metre?
At ideal efficiency, one tonne raised by one metre stores about 0.002724 kWh. At 80% efficiency, that becomes about 0.002179 kWh, or 2.179 Wh, of delivered energy per tonne per metre of vertical drop.
What mass and height combination reaches about 1 MWh?
At 80% efficiency, about 459,000 tonne-metres of mass-height product delivers 1 MWh. For illustration, 1,000 tonnes over 500 metres, 2,500 tonnes over 200 metres, or 5,000 tonnes over 100 metres each deliver about 1.09 MWh before considering project-specific constraints.
When do gravity storage and electrochemical BESS solve different problems?
Gravity storage depends on a practical moving mass, vertical path and mechanical-civil system. Electrochemical BESS stores energy in battery cells and does not require a vertical drop. The right approach depends on site geometry, operating profile, safety requirements and project economics.
Test the constraints behind gravity storage.
Read about energy density, mechanical power and real site constraints before treating a potential-energy number as a deployable design.