Pumped storage hydropower is the largest and oldest form of energy storage across the globe. Moreover, it is the most efficient form of grid-scale energy storage.
Additionally, pumped storages offer exceptional ancillary services including voltage regulation and electric frequency control, ensuring reliable and smooth power transmission in grid systems.
Besides orthodox hydro plants, PSH is also one of the most viable options for rebooting power in a grid, post blackout.
Alongside all the mentioned pros of pumped storage, one major driving factor in the growth of PSH popularity is the transition of electricity generation worldwide to eco-friendlier options: Intermittent Renewable Energy Sources (IRES).
What impact this global motive posits on the importance of pumped storage hydropower is discussed in detail below.
History of Pumped Storage Hydropower
The first use of ‘pumped storage’ dates to 1907 in Schaffhausen, Switzerland.
In the 1930s reversible hydroelectric turbines were manufactured. This laid the groundwork for modern pumped storage hydropower plants that presently use Francis Turbines which can operate as both, a turbine generator, and as an electric motor-driven pump in reverse.
This pumped storage was first introduced in the United States by the Connecticut Electric and Power Company, using a large reservoir located near New Milford, Connecticut. Water was pumped from the Housatonic River to the storage reservoir 70 meters (230ft) above.
Many of the pumped storage plants currently operational all around the world were built in the 1970s!
PSH power plants in the USA were mainly built between 1960 and 1990. Since then, pumped storage power plants have become the largest source of electrical energy storage technology used in the United States, both in terms of the number of plants as well as capacity.
Nations and Hydropower Storages
Pumped Hydroelectric Energy Storage is the most widely established bulk Electrical Energy Storage system (a global installed capacity of about 130 GW) at this date. It has been a significant part of many markets since the 1960s.
China is leading the world in terms of pumped storage hydropower capacity according to the 2019 ranking. Followed by Japan and the United States who are proximal to each other.
Besides these three, the relative capacity of almost all other countries is far from their original potential. However, the significance of these hydropower EES systems is growing with the introduction of intermittent renewable energy sources in national and international power industries as the primary sources.
Many western nations have been working on their Electrical Energy Storage systems to cope with their demands of smoothing energy transmission through their grids. In that respect, countries like Italy, Spain, the United Kingdom, France, Switzerland, and Belgium among others have national pumped hydropower capacities ranging from 1000 – 5000MW.
Moreover, there are vigorous developments taking place in the pumped storage industry throughout the world. Countries like India, South Korea, Indonesia, and Australia are also entering the market with under-construction projects due to become operational by 2022-2026.
Nevertheless, it does not seem like any nation is overtaking China in this race anytime soon. China, apart from the operational 30,290MW power capacity as of 2019, has more than 20 new projects that are under construction due to become operational in the next decade. This would boost their capacity to at least 55,000MW!
*bar chart portraying comparison of countries and their number of pumped storages
Pumped Storage Projects Across the Globe
According to the International Hydropower Association, pumped storages store up to 9000 GWh of electrical energy as a rough global aggregate. And total installed power generation capacity of this industry is 158 GW, as of 2019.
Out of this massive collection, we are going to discuss a small chunk of more popular projects that might give us a vague concept of the plants on a case-by-case basis.
Plants Larger than 1000MW Power Capacity
Currently, operational pumped storage classified as ‘Large’ (in this article) ranges from as big as 3000MW capacity to the bare minimum threshold of 1000MW.
Bath County Pumped Storage Station (USA)
This massive PSH plant present in Virginia, United States is most described as the “largest battery in the world”. The maximum generation capacity of this project is a little over 3000 MW and a total storage capacity of 24000 MWh. [1]
The power station was undergoing construction in the late 1970’s just like most currently operating pumped storage projects in the USA. And was completed in December of 1985.
As the description suggests, it is currently the largest Pumped Storage in the world!
Huizhou Pumped Storage Power Station (China)
Currently, China’s largest capacity pumped storage, Huizhou PSPS was constructed quite recently. It became fully operational in 2011. Present in the Guangdong province, it comprises 8 pump-generators that total a 2448 MW maximum power generation capacity.
One interesting, yet not unique, feature about this pumped storage is the fact that the power station of this project is located 420 meters under the ground. [2]
Tumut Hydroelectric Power Station (Australia)
This project is a series of five hydroelectric power stations on the Tumut River in New South Wales, Australia. This entire project is part of the Snowy Mountain Scheme.
Tumut 1 and Tumut 2 are underground power stations. Although, what we are concerned with is Tumut 3.
Tumut 3 power station is the first pumped storage plant in Australia. The plant contains six turbines fitted with their separate generators which provide a cumulative generating capacity of 1800MW. [3]
Grand ’Maison Dam (France)
This embankment dam present in Vaujany of Isere in the French Alps serves as the upper reservoir for a pumped storage scheme with Lac Du Verney located lower in the valley as the lower reservoir.
This power station of generating capacity 1800 MW was commissioned in 1987, following the construction of the dam during 1978-85.
This project is the largest hydroelectric power station in France. [4]
Okutataragi Pumped Storage Station (Japan)
This pumped-storage power station is in Asago, in the Hyogo Prefecture of Japan. This project took four years to construct and was inaugurated in 1974 with a maximum power generation capacity of 1932 MW.
The upper and lower reservoirs of this project (Kurokawa reservoir and Tataragi reservoir) are also known for being beautiful tourist attractions. [5]
Dinorwig Power Station (UK)
Locally Known as Electric Mountain, the Dinorwig power station is a pumped storage scheme near Llanberis in Snowdonia national park in Gwynedd, Northern Wales. The scheme having a storage capacity of 9.1GWh can supply power up to 1728 MW.
The project was originally constructed in the abandoned Dinorwic slate quarry to preserve the Snowdonia National Park. Hence, the power station itself is located deep inside tunnels and caverns in the mountain Elidir Fawr. [6]
*world map with currently existing PSH plants marked on it.
Besides the aforementioned projects, there are more than 20 well-known large-scale pumped storage projects across the globe with power generation capacities above 1000 MW. Apart from this, globally, there are at least 30 more planned or under construction projects currently due to commence operation in the next decade.
Small-Scale PSH Projects
Pumped storage systems are widely known around the world, however, only exclusively on a large scale. Pondering upon that, researchers from the ULB Brussels School of Engineering, France, investigated the possibility of energy storage through pumped hydro systems on very small scales – a building.
Even though the idea sounds fascinating, given the high probability of an increasing role of distributed energy storage systems at nuclear levels in the near future. This investigation could have proven groundbreaking, but it turns out the economies of scale that factor largely into the large-scale pumped storages is missing from this particular innovation making it ‘not ideally efficient’
Even so, pumped storage hydropower plants are not that uncommon on a relatively smaller scale – less than 1000 MW power generation capacity.
In fact, all the currently operational 2612 MW of pumped storage hydropower in India are under 1000 MW with the range going to as low as 12 MW.
Moreover, some sources claimed Europe’s total pumped storage generation capacity to be 45 GW as of 2011. Further adding that this figure comprised around 170 pumped storage plants. This loosely translates to the fact that a vast majority of these projects (if not all) were small-scale with an average capacity of as low as 260 MW.
Australia’s Pumped Storage Plans
Solar photovoltaic and wind power constitute almost 100% of Australia’s newly installed energy generation capacity every year since the last decade! Additionally, as discussed above, IRES generated power is significantly variable.
In this case, when the proportion of renewable energy out of total energy production of the country rises above 50%, considerable energy reserves will be required.
PSH has a 97% share in the entire world’s storage capacities! Based on that we can safely infer that pumped storages would have an edge in the debate over viable options for storages which include natural gas, nuclear, photovoltaic, wind, and coal, besides PSH.
Moreover, stronger interstate interconnections along with demand management will help smooth out grid-scale transmission by complementing the instant power generation feature of pumped storage.
Apart from the Tumut 3 pumped storage plant, an Australian National University study entailed the identification of about 3000 potential yet economical sites around Australia for Pumped storage installation. The identified sites cumulatively have a storage potential of about 163000 GWh.
In layman’s terms, this figure far exceeds the PSH storage requirement to transition the entire country to a 100% renewable electricity system – that is 450GWh.