Renewable generation implementation is increasing across the US. New challenges for the nation’s grid arise with this growth—resource volatility, regulation, grid operations. Advanced storage offers promising solutions for renewables interconnection. 

Richard Wakefield, KEMA VP of power system planning and management, offered insight into renewable integration with advanced storage devices at the 2009 Commonwealth of Virginia Energy Symposium (COVES). Focused on “The New Energy Future,” the event was held in Lexington, VA on October 7, 2009 (www.vmi.edu/coves). This post offers a summary of Dick’s presentation:

In the future, utilities will operate an intelligent network—one that is supported by a portfolio of technologies and advanced communications. Renewable generation implementation is increasing across the US, with 28 States having renewable portfolio standards (RPS) in place and five States with set renewable energy goals.

As renewable penetration increases, a number of issues arise with interconnecting the new generation sources into the grid. There will be a greater impact of minute-to-minute volatility. As a result, characteristics of storms and the onset / fall of wind will need to be more closely monitored. Renewable dynamic behavior will have an impact on real time energy needs, market prices, and total real-time energy costs. Traditional power plants will also feel an impact as they are required to “make up” the regulation needs imposed by renewables. And dynamics can place strains on maintaining grid operations.

Characteristics of advanced storage that allow it to assist with renewable integration include fast response characteristics for regulation and operations. Its transportability also allows devices to be placed at any location. Some promising examples include accommodating transmission limits from remote generators, reducing transmission congestion, and providing improved frequency regulation.

Energy storage can serve as an improved regulating / balancing resource. Generation and load must be kept in balance in real-time. Renewables make this more difficult when considering large, rapid swings in wind farm outputs and sudden losses or increases in PV output. Large Imbalances result in frequency excursions. Advanced storage provides faster response than conventional resources and may reduce carbon emissions as well.

Advanced storage can reduce the volatility of renewable deliveries from remote sites. Increased T&D congestion may be relieved with storage on “load-side” and fast energy storage may be an improved substitute for conventional (non-renewable) regulating reserves. Other promising applications also exist, but economics are unclear at present.