Pumped Storage Hydropower – an electricity storage solution

With renewable-based electricity generation costs now lower than fossil fuel-based generation, and greater awareness of the need to reduce carbon emissions, the issue of electrical energy storage is increasingly important. As variable renewable generators – such as wind and solar – adjust their output based on weather conditions, their output storage is essential.

Pumped storage hydropower (PSH) is a grid-scale electrical energy storage (EES) technology that works by using excess electricity (such as when demand is low or generation is high), to pump water to an upper reservoir. When demand is high, or generation is low, the water is released from the upper reservoir through a hydropower turbine and into a lower reservoir. PSH projects are increasingly being put into operation across the globe including in the US, Australia, China and Japan.

The Asia-Pacific Economic Cooperation (APEC) Workshop on the Use of Pumped Storage Hydropower to Enable Greater Renewable Energy Use and Reliable Electricity Supply examined PSH capabilities in 24 Pacific Rim economies.

With support from AWP and APEC, the project focused on PSH because of its cost advantages, low greenhouse gas emissions, and its potential to be implemented off-river with minimal negative environmental and social impacts.

Aptly put by Matt Stocks from the Australian National University, “there is over 100 times as much PSH storage potential globally as would be required to support 100 percent global variable renewable energy-based electricity supply.” In short, only sites where environmental and social impacts would be minimal, or positive, would need to be developed to meet this outcome.

With an aim to develop options for PSH as a proven energy storage option, the project focused on:

  • the role of PSH in future electricity systems
  • opportunities to modify existing infrastructure for pumped storage hydropower
  • sustainability protocols to minimise negative impacts on people and the environment
  • building a network of people and programs to enhance PSH development opportunities.

The project workshop focused on Pumped Storage Hydropower in APEC and Mekong economies, showcasing siting tools, case studies, costs and financing and environmental impacts.

With workshop participants spanning multi-lateral development organisations, government agencies, research institutions, commercial enterprises, and independent consultants, the workshop concluded that PSH is the most attractive large-scale EES technology due to its maturity, low CO2 emissions, cost effectiveness and low environmental impacts. The technology has a high number of charge-discharge cycles, and system construction costs are largely spent locally, benefiting local economies.

While PSH development is capital intensive and can take up to 10 years, requiring enhanced financing models for economic viability, it is suited for bulk energy storage and longer-term firming.

There are tools and information available to assist governments and businesses develop environmental and socially sustainable Pumped Storage Hydropower.

For more information, the below policy brief titled ‘Pumped Storage Hydropower for the Mekong Region‘ summarises key opportunities and lessons from the project to enhance energy policies and supply using pumped-storage for political and government leaders.

PSH is the most attractive large-scale storage option for the Mekong region because of its maturity, low cost, low carbon credentials, and because of the large number of potential sites identified. With sound planning and management, PSH can be designed to have minimal (or positive) environmental and social impacts.

This project was supported by AWP and APEC, and was jointly implemented by the ANU and Daniel Gilfillan Consulting between July 2020 and December 2021, with the workshop itself being held in February 2021.

Pumped Storage Hydropower for the Mekong Region (PDF, 288KB)


Feature image: Schematic of a typical PSH configuration. Source: Adapted from ARENA, 2021.
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