Pumped storage hydro’s vital role in Australia’s renewable future

By Sean Novis, Office and Project Assistant, Genex

Pumped storage hydro projects can play an increasingly vital role in the future of Australia’s renewable energy landscape. They provide a number of functionalities which are an essential complement to Australia’s growing solar and wind fleet. Pumped storage hydro (PSH), acting as a giant water battery, can provide large-scale storage capacity, energy balancing capability and ancillary grid services, all being important factors that will facilitate Australian states in meeting aggressive renewable energy targets.

UTILITY-SCALE STORAGE

Whilst the abundant solar and wind resources in Australia provide great opportunities for developers, these resources are -- by nature -- intermittent, and are often generated during periods of low consumer demand. During these times, a large amount of generated energy is essentially wasted – unless it can be stored at a large scale. Accordingly, there is an urgent need for utility-scale storage solutions in Australia.

Compared to conventional batteries that are typically smaller and can only store enough energy for a few hours of electricity, PSH is a larger, longer-term solution. Genex Power’s Kidston Pumped Storage Hydro Project (KPSH) in Kidston, Far North Queensland, will have up to 2GW of storage capacity (eight hours of storage) and will store excess energy including that generated from the company’s adjacent solar and wind projects.

As solar and wind projects continue to be built in increasing numbers around Australia, PSH has emerged as the most viable solution to address the need for utility-scale storage.

ENERGY BALANCING

To function properly, power grids need to match electricity supply and demand in real time to avoid shortages or overloads in the system. However, the generation and subsequent supply of solar and wind energy into the grid is unpredictable and does not fully align with energy demand at any given time. As Australia continues to transition to a solar and wind dominated electricity system, the ability to store energy and dispatch it at optimal times is essential for a functioning electricity grid.

PSH provides this capability at a large scale and in a cost-efficient manner. Using Genex Power’s KPSH as an example – water is pumped from a lower reservoir to an upper reservoir when prices and demand are low, and then during times of high pricing and demand, water is released back into the lower reservoir. By simply channelling water through rotating turbines and into the lower reservoir, energy is produced quickly and cheaply, and is always available for dispatch into the grid.

The capacity firming capability of PSH enables the variable output from large-scale solar and wind farms to be maintained at a committed level. This provides much needed assistance in reducing the volatility of renewable energy generation, as the storage ability of PSH can control the output and ramp rate of generators, thereby eliminating rapid voltage and power swings on the electrical grid. In this way, the supply and demand of electricity in the power grid continuously remains in equilibrium.

ANCILLARY GRID SERVICES

A significant benefit of PSH is its ability to service the Frequency Control Ancillary Services (FCAS) markets. Similar to the energy market, the FCAS markets are operated by the Australian Energy Market Operator in order to maintain the frequency of the system and provide stability to the grid. By bidding into these markets, PSH can respond to large electrical load changes within seconds.

Furthermore, in the event of a power station shutdown, the black start capability of PSH projects allows them to restore large power stations to full operation without reliance on external power transmission networks. Restoring large power stations rapidly will prevent the prolonged loss of power caused by blackouts for many homes and businesses across Australia.

Another useful application is during extreme weather events, where the operating reserve capacity of PSH can meet energy demands in the case that supply is disrupted. When generators stop working due to extreme weather, entire communities may lose electricity for several hours, and technologies such as PSH can step in to supply these loads.

CONCLUSIONS

This article has discussed three key capabilities of PSH that highlight its critical role in Australia’s renewable energy future. Its ability to provide large-scale energy storage ensures that as Australia relies more heavily on solar and wind energy, losses due to inefficient generation will be minimised.

Furthermore, PSH can balance load on the energy system, allowing clean generating sources to operate at peak efficiencies, which is particularly useful in a renewables environment characterised by intermittent energy generation.

Finally, by integrating into FCAS markets, PSH projects can quickly remedy extreme disruptions to power supply across Australia.