By Weston J. Sylvester, Siemens Energy
Throughout the world of transmission and distribution, the topic of smart grid has been at the forefront for a few years now and the injection of stimulus dollars to support these effortsin both demonstration and deploymenthas encouraged the movement toward a more intelligent grid. Regardless of the scope of a utility’s smart grid program, there can be an impact on both the large-scale and distributed generation (DG) level that must be addressed.
Oftentimes the impact of smart grid on generation has to be understood from the program level working backward. Centering the discussion on the consumer typically helps and focusing on three areas of “smart” gives a perspective on what some of the impacts might be. While there are many technologies that are being thought about for the future of our gridfrom the practical to the extremedemand response, grid automation and microgrids are all technologies that are being implemented today, which means the consideration for generation needs to be addressed.
While there are many variations on what demand response is or does, an impact on generation at all levels is possible. Using load profiling and the effects of aggregation, lowering the overall peak load in all seasons can offset the need for new large-scale generation and/or peaking plants. Often this offset need can make a huge impact on the business case for a demand response program.
Grid automation has a major role to play in many smart grid roll-outs and the effect on generation is dramatic at the distributed generation level. When a utility (or a consumer) installs photovoltaic solar panels, wind generation or even typical standby industrial generation, the dynamics of the grid change since power can flow “both ways” depending on how much distributed generation is available. Grid automation, both in the substation and on the feeder, helps to integrate DG, especially once the probable need for storage is considered. Switching back and forth from the spinning generation to a wind generator, or compensating a peak load by dispatching stored energy from a sodium sulfur battery that was charged overnight (either by large-scale or distributed generation power source) is clearly a place for automation. Without it, the value of all of these programs is significantly reduced, due to the quickly changing landscape of grid dynamics.
Microgrids are a unique discussion also. Whether it’s a university campus or a green community, the concept of having a section of load capable of sustaining itself either short term or long term can have impacts at the generation level. If a university campus, for example, can support itself and be “islanded” thanks to wind generation and energy storage (allowing the wind to power the campus, even when the wind isn’t blowing), it clearly impacts the necessary large-scale generation.
There is still a lot to be learned about how smart grid programs and generation will coexist today and in the future. All of the programs listed above have common questions that will have to be answered as we move toward an energy age where generation, transmission and distribution are even more intertwined. If the intent is carbon footprint reduction, can we really reduce spinning reserves? If a cloud rolls over a solar array, or a consumer overrides a demand response event, or a microgrid needs grid support just as the larger grid is reaching its own peak, what is the reaction of the grid? The lights have to stay on.
Grid automation and proper planning will help answer these types of questions; the utilities and vendors that have a perspective that integrates thinking from generation to consumer will be at the forefront. Most, if not all, of the programs that can be implemented for smart grid can impact not only generation but other smart grid programs, which means the business cases will have to work together. Planning and modeling the impacts, having a long-term vision, understanding the technology limits and recognizing where one business case for distributed generation may require another business case for automation or transmission infrastructure will be key to all our futures.
Author: Wes Sylvester is director, Distribution Solutions & Smart Grid, at Siemens Energy Inc., responsible for solution vision, direction, strategy, definition, design, sales and marketing for distribution products and services, with an emphasis on smart grid solutions. Mr. Sylvester previously held various roles of increasing responsibility at Cooper Power Systems in both sales and marketing. He holds a Bachelor of Science in mechanical engineering from the Milwaukee School of Engineering.