24 July 2012
Among the many important topics discussed recently during the Intersolar North America conference in San Francisco, one of the more intriguing was energy storage and how technologies like advanced batteries can facilitate the increased integration of renewable generation onto the grid.
With the increased penetration of renewable generation, the grid is experiencing a shift from predictable, dispatchable generation to variable, non-dispatchable generation. This adds a new level of uncertainty and volatility to the grid that can cause an array of problems as the relative proportion of variable generation versus traditional dispatchable generation increases. Since generation from renewable sources is unpredictable, it becomes difficult to schedule and manage traditional generation assets to compensate.
Grid operators and renewable power products are struggling to respond to these changes, and possible options such as adding additional gas turbines to compensate for the variability of renewables not only counteracts the benefits and purpose of deploying renewable sources, but they are also less effective in providing the fast response needed.
Conversely, energy storage can be deployed to address the unpredictability of renewable generation, allowing it to respond more like traditional generation. This will enable renewable resources to meet more stringent operational performance standards being established to mitigate the effects of increased amounts of variable generation being integrated into the grid. From a technical perspective, energy storage can address most of the issues associated with intermittent renewable energy generation, including shifting of energy in time to “smooth” the output of renewable generation or reduce the peak load on constrained transmission and distribution assets. In addition, inverters used to connect large-scale battery systems to electrical grids can provide reactive power as a coincident service that can help with voltage support, and related performance requirements.
And while there is some debate about the commercially readiness of energy storage, there are a number of large-scale energy storage systems globally that are currently in commercial operation or in development, indicating that utilities and power produces see a strong business case for using energy storage for renewable integration, including for solar PV.
In fact, to further enhance the economic value proposition, some power producers are leveraging storage assets for multiple applications. For example, the AES Laurel Mountain Wind Farm (seen in photo) in West Virginia features a 32MW/8MWh energy storage solution that provides ramp management for renewable generation as well as flexible operating reserve capacity to the PJM Interconnection.
As AES and others continue to demonstrate, fast, flexible and scalable energy storage solutions, including advanced battery systems, can expand the effective capacity of traditional grid infrastructure to enable the integration and delivery of renewable generation. With field-proven results and policymakers opening the electricity market to new technologies, the deployment of energy storage systems alongside renewable generation is a trend that will likely continue.
Written by Chris Campbell, Vice President of Marketing and Business Development, Energy Solutions Group, at A123 Systems in Waltham, Massachusetts (US), a developer and manufacturer of advanced Nanophosphate lithium iron phosphate batteries and energy storage systems for the transportation, electric grid and commercial markets.