| Energy storage The study compared pumped storage hydropower


to four other technologies: compressed-air energy storage (CAES), utility-scale lithium-ion batteries (LIBs), utility-scale lead-acid (PbAc) batteries, and vanadium redox flow batteries (VRFBs). While CAES and pumped storage hydropower are designed for long-duration storage, batteries are intended for shorter-term use. Inman highlighted: “Not all energy storage


technologies provide the same services. We looked at compressed-air energy storage, which allows for grid-scale energy storage and provides services like grid inertia and resilience. But pumped storage hydropower is about a quarter of the greenhouse gas emissions compared to compressed air.” The researchers based their analysis on 39


preliminary designs from 35 proposed sites across the contiguous US. They assumed an average closed- loop pump storage hydropower facility would have a storage capacity of 835MW and deliver an estimated average of 2060GWh of stored energy annually. Their base scenario considered an electricity mix sourced entirely from renewable technologies. The study estimated that the GWP associated with 1 kWh of stored electricity delivered to the nearest grid substation connection point for pumped storage hydropower ranged from 58 to 502 grams of carbon dioxide per kWh. Hydropower stood out as the leader in terms of GWP on a functional unit basis, followed by LIBs, VRFBs, CAES, and PbAc. Additionally, the researchers discovered that certain decisions, such as building on a brownfield site rather than a greenfield site, could reduce the GWP by as much as 20%. The research was funded by the US Department of Energy’s Water Power Technologies Office.


Calls for more support in the UK Neil Gray MSP, the Cabinet Secretary for Energy in the Scottish Government, has recently urged the UK Government to provide developers with the necessary assurance to support the establishment of a fresh wave of pumped storage hydroelectric plants. This initiative holds the potential to foster the creation of nearly 15,000 job opportunities and facilitate the expansion of renewable electricity generation. Gray voiced his endorsement for this endeavour during a visit to the Cruachan Power Station in Argyll, operated by renewable energy firm Drax. The company is actively advancing plans for a £500 million subterranean pumped storage hydro facility at the Cruachan site. This ambitious expansion of the UK’s pumped storage hydro capabilities is deemed crucial for effectively assimilating the growing output from wind and solar power sources into the energy grid. This strategic enhancement not only fortifies energy security but also aligns with the nation’s commitment to combat climate change. Despite the imperative nature of these facilities, the UK has not commissioned new pumped storage plants since 1984. This is largely attributed to the inadequacy of existing support frameworks, designed for different technologies and not tailored to the distinctive requirements of these expansive infrastructure ventures. A comprehensive report authored by KPMG underscored the feasibility of implementing a cap and floor mechanism, akin to the incentive systems employed for cross-border interconnectors. This approach could potentially surmount the existing


impediments obstructing investment in extended- duration energy storage technologies. “To achieve a safe and secure net zero power grid, we need to have a new generation of pumped storage hydro plants to balance our grid,” commented Ian Kinnaird, Drax’s Scottish Assets Director. “As the UK increasingly relies on intermittent renewables to keep our lights on, there is a growing need for flexible power sources to plug the gap when the wind doesn’t blow, or the sun doesn’t shine. With its reversible turbines, Cruachan can also store excess power from Scotland’s wind turbines when they are generating more renewable electricity than we need, helping to stop valuable green power from going to waste.” With appropriate backing from the UK Government, Drax is poised to inject a substantial £500 million investment into doubling Cruachan’s energy generation capacity, consequently fostering the creation of nearly 1,000 jobs throughout the supply chain during the construction phase. “Scotland is a global leader in the production of


renewable energy, which will play an increasingly important role in the transition to a net zero electricity system by 2045,” commented Neil Gray MSP. “However, pumped hydro storage, an important low carbon technology, is currently ineligible for UK Government support. UK Government inaction on this issue represents a significant obstacle to progress and risks failing to secure economic benefits, such as creating thousands of good quality, green jobs.” A recent report commissioned by trade body Scottish Renewables unveiled that the establishment of a new wave of pumped storage hydro plants across Scotland could yield nearly 15,000 jobs across the UK. Drax’s proposed expansion of the Cruachan facility alone could contribute almost half a billion pounds to the UK economy.


New developments A number of projects are being planned elsewhere


in the world. EnergyAustralia has announced its commencement of comprehensive technical and environmental studies for the proposed Lake Lyell pumped storage hydropower project. The project is slated to be established on EnergyAustralia-owned land in close proximity to Lithgow in New South Wales.


Below: View of early construction work at the Hatta pumped storage project in Dubai. The project is now 74% complete


www.waterpowermagazine.com | October 2023 | 31


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