By Jennifer Eirich, Marketing Manager, Utilities, EnerSys
Mother Nature has become a formidable force in the last few decades. In the 1980s, the United States (U.S.) experienced 20 weather disasters, in the 1990s, 47 and, in the 2000s, 48. Unfortunately, the situation is getting worse. In the past four years alone, the U.S. experienced 36 weather disasters -- more than double the pace of the previous two decades!1
The winter of 2014-2015 also promises not to disappoint. Joe Bastardi, chief meteorologist at WeatherBELL Analytics, says that current weather is “flowing along right now into the type of El Niño situation that is notorious for giving the U.S. cold, snowy winters.”2 The increasing severity of weather-related events has sparked a growing interest in modernizing the electric grid to improve both reliability and resilience.
According to the 2014 Department of Energy “Smart Grid System Report,” emerging technologies such as energy storage and solid-state devices, as well as information management and control systems and microgrids, are being introduced to improve resilience and stability.3
New, smart microgrids are not the panacea for system resiliency and reliability.
As Michael Roach of MicroGrid Horizons put it in his white paper entitled, “Hurricane Sandy & the Emperor’s New Clothes: Microgrids as a Risk Mitigation Strategy for Extreme Weather Events,” “The grid is most vulnerable at the distribution level where pole-strung electric lines deliver the final mile to customers. Trees, electric wires and hurricane winds just don’t get along with each other no matter how ‘smart’ the grid is. At the distribution level, the grid is inherently vulnerable and impossible to fix without truly massive investments burying lines and elevating distribution switch gear. By design, ‘all of the eggs are in one basket.’”
As a result, utility designers are faced with a two-fold challenge: to enhance systems with new, more responsive smart grid technology, while hardening infrastructure to withstand future attacks from Mother Nature. The hardening process begins with an essential building block -- the backup switchgear battery.
Here are a few tips for choosing a battery for your backup energy storage needs: · One-minute rate: Often, the first minute of the duty cycle, where critical breaker tripping operations occur, will be the determining factor in the size or capacity of the battery required. Be sure to review the sizing calculations for the particular site before selecting a battery based on ampere-hour rating alone.4
· Design/operational life: It is important to distinguish between warranty term and design life. European and North American batteries, for example, are specified on different specific gravity and operating temperature ranges. This must be taken into account when comparing the two because higher temperature and higher specific gravity will increase the grid corrosion rate, and, therefore, decrease the life expectancy.5
· Shelf life: If your battery is not installed immediately, be sure to apply a freshening charge before installation and calculate this into the procurement cost.6
· Hydrogen evolution: Many substations were constructed years ago with a specific battery chemistry in mind. Check the ventilation requirements because gassing rates may differ if you are now using a different battery chemistry.7
· Life Cycle Cost: When selecting a battery, the ampere-hour rating provides a gauge for estimating a specific workload within an established length of time. However, when factors such as design temperature and specific gravity increase or decrease operational life, overall cost is also affected and must be taken into account. This is especially true when comparing U.S. versus European batteries, in which ampere-hour ratings may be based on a different combination of factors.
· Chemistry: It is important to match the right battery to the application.
o Nickel Cadmium (NiCd): NiCd batteries may prove to be more cost-effective than lead acid. They tolerate abuse and provide long life, but care must be taken to condition the batteries once per year to reverse the float de-rating effect. They also are costly to recycle.
o Flooded Lead Acid: Flat plate flooded lead acid batteries are the primary choice for stationary applications. They are robust, cost-effective, flexible and easy to recycle. They are a bit heavier, however, and do require watering and maintenance.8
o Tubular Lead Acid: These batteries offer excellent cycling capabilities and a proven long life under float conditions. As such, they have been increasingly marketed for stationary float applications, such as utility switchgear, as a potentially lower cost solution. Like flooded batteries, they are heavy to handle, however.
o Thin Plate Pure Lead (TPPL): Pure lead plate designs are free from impurities and corrosion and provide considerable energy density improvement over NiCd and flooded lead acid battery technologies. Although the pure lead design is a bit higher in cost, this can be offset by its longer life, maintenance-free operation and ease of recycling.
With the Buffalo, N,Y. superstorm kicking things off with six feet of snow, our winter is already off to a chilling start. Today’s increasing weather events can have an impact on our already vulnerable utility transmission and distribution network. Statistically, the number one reason standby generators fail to start is due to dead starting batteries -- with over 80 percent of all starting failures from this cause.9 System hardening, beginning with the starting battery, can provide a layer of protection for our fragile grid by helping to boost utility reliability and resiliency. For more information, visit www.enersys.com.
EnerSys, the global leader in stored energy solutions for industrial applications, manufactures and distributes reserve power and motive power batteries, battery chargers, power equipment, battery accessories and outdoor equipment enclosure solutions to customers worldwide. Motive power batteries and chargers are utilized in electric forklift trucks and other commercial electric powered vehicles. Reserve power batteries are used in the telecommunication and utility industries, uninterruptible power supplies, and numerous applications requiring stored energy solutions including medical, aerospace and defense systems. Outdoor equipment enclosure products are utilized in the telecommunication, cable, utility, transportation industries and by government and defense customers. The company also provides aftermarket and customer support services to its customers from over 100 countries through its sales and manufacturing locations around the world.
About the author:
Jennifer Eirich is the marketing manager, Utilities, at EnerSys. Eirich received her Bachelor of Science in Chemical Engineering from Pennsylvania State University.
1 “Severe Weather and Manufacturing in America: Comparing the Cost of Droughts, Storms and Extreme Temperatures with the Cost of New EPA Standards,” Business Forward Foundation, June 2014
2 “This Year's Winter Shaping Up to Be Colder, Snowier,” WSJ Video. August 11.2014. http://www.wsj.com/video/this-year-winter-shaping-up-to-be-colder-snowier/857DA4C5-FF31-46EE-A859-CCD7CFEDBE4E.html?mod=trending_now_video_2#!1B4EFEF0-1FA0-4F15-8C10-5110B23758B9
3 2014 Smart Grid System Report, Department of Energy, August 2014.
4 Stephen L Vechy, Marketing Director, EnerSys, “Important Considerations in Selecting A Flooded Lead Acid Battery for a Utility Switchgear Application,” 2008.
5 Stephen L Vechy, Marketing Director, EnerSys, “Important Considerations in Selecting A Flooded Lead Acid Battery for a Utility Switchgear Application,” 2008.
6Stephen L Vechy, Marketing Director, EnerSys, “Important Considerations in Selecting A Flooded Lead Acid Battery for a Utility Switchgear Application,” 2008.
7Stephen L Vechy, Marketing Director, EnerSys, “Important Considerations in Selecting A Flooded Lead Acid Battery for a Utility Switchgear Application,” 2008.
8Stephen L Vechy, Marketing Director, EnerSys, Advanced Electrochemical Energy Storage Technologies for Stationary Power Applications,” 2006
9 James R Iverson, “Digital Control Technology Enhances Power System Reliability and Performance,” Cummins Power Generation, publication F-1536, 2004.