EnergyBank is developing a new form of grid-scale, medium and long-duration energy storage. It’s ocean-based gravity battery, which is connected to the grid via an undersea cable, moves iron-ore aggregate masses between the ocean surface and floor. It stores energy as gravitational potential, then releases it by lowering the weights.

Customer Focus

EnergyBank will eventually operate storage-as-a-service for electricity generators, distributors and retailers who want to optimise the value of their assets. EnergyBank will allow them to smooth supply/demand of renewable energy, thereby reducing the need for fossil fuels to meet peak grid demand.

EnergyBank has a long journey ahead of them before this technology will be bankable. Therefore they are developing innovative alternative market entry points to validate their technology. These will be significantly less capital intensive, avoid regulatory interference and have a far more desirable customer base than existing incumbent utilities. Watch this space.

Compared to alternative storage technologies like pumped-hydro dams, whose location is constrained by particular geographic features and whose construction is often environmentally destructive, EnergyBank can position its batteries close to demand centres. EnergyBank’s technology is applicable to the >40 countries where high energy-demand cities are located near deep ocean topography.


EnergyBank is in the early stages of developing its battery and many challenges remain. EnergyBank can draw on a number of technologies already in widespread use for deep sea oil & gas operations to engineer its solution; but the team is also innovating proprietary elements, notably:

  • low-wear, ultra-high-efficiency winches
  • low-drag, foul-free tethers
  • ultra-reliable, deep-sea grabbers
  • resonance-damping model predictive controls


Renewable energy generation is a critical enabler of a net zero-emissions economy. But, achieving 100% renewable energy supply is impossible without effective energy storage. Storage is needed to offtake supply when renewable sources like wind and solar are generating excess energy, and provide supply back to the grid when those generating sources fall short of grid needs.

Today, periods of high grid demand are often met by fossil fuel generation which can be turned on to manage peak loads. Given they are the only viable solution, fossil fuelled electricity supplied in this way attracts a price premium; while renewables (which tend to be available all at once, when the sun is shining or wind is blowing) tend to lose pricing power.

An effective storage solution for renewable energy providers would allow them to store excess energy not needed at the time it is generated. Being able to provide energy at times of peak demand would help them optimise the price they can attract for the energy they have generated, while reducing the need for fossil fuels.

Leveraging the more than 4,000m depths available near many major cities, EnergyBank’s ocean batteries can store considerably more energy per unit mass than other gravitational potential energy storage technologies and plans are already under development for integration with offshore wind farms.

From the Founders

  • Company Name:¬† EnergyBank
  • Themes: Energy Storage, Offshore Wind, Datacentres, Crypto Mining.
  • Summary: Developing deep ocean gravitational energy storage technology.
  • Product stage: Early Feasibility Studies/Prototyping
  • Founder: Tim Hawkey, Rhys Foster, Jordan Hooper
  • Capital raising: 1 seed round, $2.7m on $8m pre-money.
  • Company mission: Catalyse the deployment of renewables.

This profile was written by Principal at Blackbird, Phoebe Harrop, who is a member of Climate Salad and champion of climate tech solutions.

Photo by Jeremy Bishop on Unsplash

Nov 10, 2021

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