Is The Combination Of Solar Plus Pumped Hydro an answer for 24-hour renewable power?
Solar and wind technologies have widescale application around the world but have the handicap of not being a continuous power source. Solar produces energy during the day and has to be coupled with a storage option to serve 24X7. So, there is a need for cheaper and larger options for storing this power and that is the key to increasing the share of renewable energy in the process of electricity production. This will gradually allow the decommission of fossil fuel-based power plants.
Recent studies show that there is a lot of potential for pumped hydro usage. A study by the Australian National University (2017), was able to find 22,000 sites that had the basic potential to pump hydro in Australia. According to Clean Technica, 530,000 sites have been found worldwide.
However, this is just the elementary possibility and other factors such as environmental, land possession and other aspects have not been considered in these studies.
The process of generating hydroelectricity is quite simple we drive water up into a reservoir and the water stored is let out on turbines to produce power whenever needed. Even with the new battery discoveries pumping hydro is still at a lower cost.
According to the International Energy Statistics, global pumped storage producing capacity was at 104GW in 2009. The European Union and Japan account for 36.8 % and 24.6 % of the worldwide capacity respectively.
This mode of storing electricity is a great way to power the grid during the night. Hydro pump storage is a method which permits sporadic sources such as solar, wind and other renewables forms of energy or surplus electricity from coal or nuclear to be stored for time periods of higher demand.
There are many benefits of utilizing these pumps such as:
I) It reduces across-the-board electricity prices.
II) Plays a key role in spreading the use of renewable resources.
III) Advanced grid operations.
However, one of the drawbacks of using hydro is often the capital cost that is fairly higher. Conversely, their long life of up to 75 years or more is a lot longer than utility-scale type batteries. Another issue that arises is that a large body of water is needed for significant storage capacity and this can be problematic in urban locations.
In 1966, the Rance Tidal Power Station (240MW) initiated in France partly worked as a pumped storage system. During, a high tide in off-peak hours this plant can bring in more seawater in than the natural tide itself. This type of large-scale system is the only one of its kind.
The Yanbaru Project (1999) in Okinawa, Japan was the first complete demonstration of seawater pumped storage and has since been withdrawn. Many more proposals for building such plants have been made for the future.
The possibilities of underground reservoirs have been studied in detail. In fact, underground projects have been proposed in the Maysville plan in Kentucky (underground mine), the Mount Hope plan in New Jersey (former iron mine lower reservoir) and another proposal in Norton Ohio. The numbers of places available for underground reservoirs are limited but this can increase if abandoned coal mines can be utilized for this purpose
Other types such as underwater and decentralized systems are all being researched and might prove to completely change the way we look at pumped hydro-electrical storage systems. Small-scale options such as pica hydro are useful in ‘closed loop’ home generating systems.
The growing opportunities to use hydroelectric pumps as a method of storing energy are immense. India has a lot of prospects in terms of hydropower and is the fifth producer globally. However, less than 25% of India’s potential capacity hasn’t been tapped into yet. The Indian market still has a lot of room to grow and develop further..