Review and analysis of energy storage systems by hydro-pumping to support a mix of electricity generation with a high percentage of renewables

Abstract

In some countries the planning of the electricity generation mix

for the future includes a considerable increase in Renewable

Energy (RE) to reduce the emissions caused by the use of

fossil fuels. This trend can be reinforced if the installed power

capacity of nuclear and coal plants is considerably decreased.

On the other hand future electricity demand seems to increase

due to population growth and greater domestic electrification,

especially if transport electrification is tackled. The combination

of these factors may result in an ever greater decline in

Security of Supply (SoS), mainly due to the stochastic nature of

electricity supply and demand behaviour.

To achieve an acceptable level of SoS when introducing

renewable energy into the grid it is necessary to increase

storage capacity and tackle other measures such as demand

management. Many energy storage technologies can be found,

and Pumped Hydro Energy Storage (PHES) is recognised as the

most mature, though other technologies such as batteries are

also available.

In this paper, we first review PHES and its ability to support

intermittent generation from energy plants, such as wind and

solar, preventing energy losses and storing energy for use at

times of high demand; second we analyse the performance

of PHES in Spain over five years (2014-2018); our conclusion

confirms that adequate SoS cannot be guaranteed with PHES

management of the kind observed in the past.