Energy storage will play a critical role in decarbonising the electricity system and reducing global carbon emissions.


Renewable sources of generation rely on the elements, such as wind and sunshine. When the wind isn’t blowing and the sun isn’t shining, energy storage will ensure Australians can still turn their lights on at a reasonable price. Rather than shifting energy between places – energy storage allows us to shift energy between times.


AEMO has forecast that the National Electricity Market (NEM) will require 46GW/640GWh of dispatchable energy storage in all its forms by 2050. At North Harbour Clean Energy, we are focussing on operationally proven storage technologies.

A mismatch between energy demand and supply across a given day


Pumped hydro has the lowest cost of storage out of all long-duration energy storage technologies due to its scalability and extended lifetime. It is a proven technology that has existed for almost 100 years and accounts for over 94% of large-scale global energy storage.


Pumped hydro operates like a battery, generating energy during peak demand and storing energy during low demand.


Hydropower energy is generated by releasing water downhill from the upper reservoir through a turbine into a lower reservoir. Pumped hydro operates on the same principle, and simply uses energy to pump the water back uphill from the lower reservoir to the upper reservoir.

Cross-section of a standard PHES system


Lowest cost due to lifetime and scale
Longest service life for energy storage
Large scale and long duration 
Sustainable, with recycling of water
Mature technology, utilised for 100 years


While pumped hydro is the cheapest form of storage, it is site constrained. The technology requires significant height differential over short distances. In comparison, batteries can be deployed anywhere. The two most established and proven battery technologies for grid scale usage are Lithium-Ion batteries and Vanadium Redox Flow Batteries (VRFBs). 


Each of these technologies have characteristics that make them suitable for different use cases, applications and storage durations.   VRFBs are less well known than Lithium-Ion batteries but were first developed in the 1980s by Maria Skyllas-Kazacos, at UNSW and have been deployed at grid-scale globally.

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