Pumped storage | On the up


Pumped storage plans are ramping up. IWP&DC gives an insight into recent developments across Australia, Canada, Greece, India, the UK, and US


Right: In the US, Oak Ridge National Laboratory and University of Tennessee have created a new method to calculate the power grid’s inertia in real time, using signals from pumped storage hydropower facilities such as TVA’s Raccoon Mountain project, near Chattanooga in Tennessee


SCIENTISTS AT THE UNIVERSITY of Tennessee, Knoxville, and Oak Ridge National Laboratory in the US have developed an algorithm to predict electric grid stability using signals from pumped storage hydropower projects. The method provides critical situational awareness as the grid increasingly shifts to intermittent renewable power. When pumps shut down, they almost always stop at


a fixed power level and this, Yilu Liu, lead for the project and UT-ORNL Governor’s Chair for Power Grids, said is a very defined signal on the grid that can help calculate overall inertia. Generation sources such as solar and wind


currently provide a minimal amount of inertia. They’re connected to the grid using inverters that convert the direct current power generated by renewables to the alternating current used to transmit electricity over long distances. The result is that grids reliant on inverter-connected renewable energy have less tolerance to abrupt change such as storm damage or unusual demand peaks. Liu and colleagues have created a new algorithm that captures the pumped storage signal and uses it along with information gathered from unique, low-cost grid sensors previously deployed across the country. Called FNET/GridEye, this sensing and measurement system was developed by ORNL and University of Tennessee researchers to monitor the grid across a wide area. Together, the pumped storage signal and sensor data produce a real-time, highly accurate estimation of grid inertia. To make it easier for grid operators to monitor inertia using the algorithm and better prepare for potential grid instability, the researchers created a visualisation interface. The new method was validated with the help of utilities and power regulating authorities in the western and eastern US where pumped storage hydropower is most prevalent. The visualisation tool is being demonstrated to utilities and grid coordinating authorities such as the


10 | March 2024 | www.waterpowermagazine.com


North American Electric Reliability Corporation, and Liu is confident that it will become more important for grid situational awareness as the system grows increasingly reliant on renewables. “Through this project we can demonstrate how important inertia is, and how pumped storage hydro can contribute to it, especially as we are looking at more intermittent renewable energy sources added to the grid,” said Shih-Chieh Kao, manager of the Water Power Programme at ORNL.


Swiss stepping stone In a move to explore opportunities for enhancing


the UK’s renewable energy landscape, Labour Shadow Secretary of State for Scotland, Ian Murray MP, embarked on a fact-finding mission to the Nant de Drance pumped storage hydroelectric project in Switzerland. The visit, conducted in collaboration with companies including Glen Earrach Energy (GEE), Green Highland, Alpiq, and AECOM, aimed to glean insights into the potential integration of similar technologies in the UK. The visit comes at a crucial time, coinciding with the UK government’s emphasis on bolstering energy storage capabilities and Labour’s commitment to position Britain as a clean energy superpower. The backdrop of the UK government’s ongoing consultation on the policy framework for long-duration electricity storage (LDES) adds significance to Murray’s exploration of the Nant de Drance project. The Labour Party has pledged to invest in long-duration energy storage to ensure a reliable zero-emission backup power supply during periods without wind or sun. The commitment also includes maintaining a strategic reserve of backup gas power stations to guarantee energy security. The tour to the Nant de Drance project, which was commissioned in 2022, provided essential lessons for the UK, particularly in the context of the country not having seen the development of new pumped


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