Universidad Politécnica de Madrid

Instituto de energía solar

Energy Storage


Renewable energies are experiencing a fast deployment worldwide. In 2013, they represented 72% of total new power generation capacity in Europe and 56% worldwide. In this context, one of the major challenges consists of storing the energy coming from these intermittent resources, such as solar and wind. It is estimated that more than 32,000 TWh of energy will need to be stored by 2035, which will require more than 6,000 GW of new energy storage installed capacity by 2030.

Today, the global energy storage capacity is less than 3% of the generation capacity and 95% of that capacity correspond to pumped hydroelectric. In some particular regions, such as northern Europe, pumped hydroelectric suffice to solve the problem, but they do not resolve the global energy storage problem. Therefore, it is mandatory to develop cost-effective solutions for the massive storage of energy worldwide, which do not depend on geographic location, or use scarce elements.

Additionally, high penetration of PV power into the electrical networks leads Transmission System Operators to establish some restricting norms to assure the stability of the grid, such as power ramp rate limitation which obliges to integrate batteries in the PV plants.

Today’s technologies do not provide a definitive solution. In the field of electricity storage, most of existing technologies are affected by scarcity of some of their constitutive elements, such as lithium, cobalt, tantalum, and rare earths. Other technologies are facing important security issues, such as hydrogen and NaS batteries. In the field of concentrated solar power (CSP), molten salts are still inefficient and high-cost.

At IES, we are working on two research lines aimed at the development and the study of innovative energy storage solutions. One of them focuses on the integration of electric storage devices in PV systems. The other one deals with development of a novel energy storage device based on molten silicon.