The drive toward clean energy is forcing utilities around the world to augment their grids with renewable energy sources like solar and wind power. However, effectively and efficiently utilizing energy generated by renewable sources means complementing the traditional grid with energy storage systems because solar cannot provide energy at night and wind turbines don’t generate electricity when the wind stops blowing.
By absorbing the extra power generated by renewable sources, energy storage is playing an important role in improving the operational capabilities of the grid during periods of peak demand or emergencies created by outages due to natural calamities. In short, grid scale energy storage is giving traditional grids new capabilities to handle energy emergencies, whether they are created by the community’s demand for more power or by natural catastrophes.
Consequently, it is not surprising to see that the grid-scale energy storage market is gaining momentum. In terms of capacity, research firm IHS estimates that the annual installation of grid-connected energy storage will increase globally from 340 MW in 2013 to over 6 GW in 2017. At this rate, the consulting firm IHS is predicting that the annual installation of grid-connected energy storage will surge to 40 GW of installations by 2022. As per this report, U.S. is the leader, accounting for nearly 43% of global installations.
Concurrently, efforts are underway to make energy storage an integral part of the country’s electricity grid. For that, U.S. Department of Energy (DoE) has generated a report titled “Grid Energy Storage”. It highlights technologies needed and challenges that must be overcome for widespread deployment of energy storage across grids in the U.S.
Per DoE’s report, there are so many ways energy can be stored. Key amongst them include:
- Pumped Hydroelectric
- Compressed air energy storage
- Batteries (Li-ion, Lead-Acid, Lead-Carbon, and Sodium Sulphur)
- Flow Battery
- Superconducting magnetics
- Thermal energy storage
- Hydrogen storage
Storage technologies that seem to dominate this sector include pumped hydroelectric, thermal, Li-ion and flow batteries, compressed air energy storage system, supercapacitors, and flywheels. DoE’s report shows that as of August 2013, there are 202 storage system deployments in the U.S. with a cumulative operational capability of 24.6 GW.
Accounting for 95% of the U.S. grid storage, pumped hydroelectric is by far the technology of choice for energy storage. Other major technologies in the 5% segment include thermal, compressed air, batteries and flywheels. According to Electric Power Research Institute (EPRI), as of March 2012, pumped hydroelectric is accounted for nearly 99% of bulk storage capacity worldwide.
Since storage can be used to support generation, transmission, and distribution, there are a number of applications driving these technologies. These include energy management, backup power, load leveling, frequency regulation, voltage support, and grid stabilization. Since each application has its unique storage requirements, there is a need for a variety of storage technologies.
However, the road to growth is not going to be smooth. To gain widespread deployment, energy storage will have to overcome four major barriers. These include cost-competitive energy storage systems, validated performance and safety, an equitable regulatory environment and industry acceptance.