Variability is the most common critique of solar technologies. The development of energy storage technologies and methods, as well as the intelligence controls to optimize deployment are critical to managing high levels of solar penetration on the distribution and transmission grid. Photovoltaic technologies can be paired with battery technology, while concentrating solar power can involve supplemental design configurations to include high-temperature solar thermal storage.
Photovoltaic electricity storage technologies can be deployed in two ways—1) directly with a specific solar installation to manage its particular output or maximize benefits, or 2) within the distribution or transmission vicinity of one or more solar installations to manage the localized or system level impacts.
The amount of storage deployed can also vary, each with differing purposes:
- Milliseconds to seconds: Provide ancillary grid balancing services
- Minutes to Hours: Provide intermittent generation smoothing from transient cloud events
- Hours: Provide localized or system level capacity benefits into evening hours
- Hours to Days: Provide on-site or micro-grid back-up services during grid outages
External factors – electric rates, solar penetration levels, electricity market structure, research and development needs, consumer preferences and needs, and most predominately, energy storage capabilities and costs—affect where energy storage is sited, who owns or manages them, and how compensation mechanisms are structured. Currently energy storage costs such that broad deployment by market forces alone is unlikely – value added situations or interests for either utility customers or utility infrastructure needs, research and development interests, or other means may be necessary for storage projects to be considered viable.
Additionally, smart intelligence is needed to deploy energy storage in reactive manners to solar output, the electric grid situation, or utility market or customer rate pricing. These supporting controls and software are equally as important to the actual utilization of the storage technologies themselves.