Combining Mission Critical Systems Protection and Environmental Citizenship
Today’s data center operators have so many demands for their time and money — dealing with system performance, uptime, energy, capacity, regulations, and security — just to name a few. Many data center managers also want to do the right thing to minimize the environmental footprint made by their often massive operations, but there is one network element that is both critical to the operation and is often seen as an environmental challenge. Batteries are utilized in nearly all data centers and are often considered environmental adversaries.
Many data center operators believe they have to choose between mission critical performance and environmental protection. However, there is a way to have both peace of mind with regards to system performance and in doing your part to protect the environment.
In addition to a winning environmental strategy, reducing waste can be financially rewarding because there are cost savings to be realized. These savings are realized via a reduction in maintenance costs and through extending the life of a battery.
Mission critical protection: automated versus manual
Before the introduction of advanced battery monitoring systems, operators relied on outside firms to test their batteries for reliability. This meant a technician would travel some distance to carry out preventive maintenance (PM) procedures. With a battery monitoring system, these trips can be reduced and many of them completely avoided since batteries can easily be monitored remotely and the data can be shared electronically.
The detail represented in the graph below is a good example of the volume of data and level of continuous resolution available when using a battery monitoring system. This level of detail cannot be provided from PM operations and even if it could, it would be costly and time consuming.
Electronic monitoring is continuous, extremely reliable and provides immediate battery health data 24x7x365.
No longer is it necessary to travel to the site of the battery to take readings and to understand the health of the battery. With advanced monitoring technology it is easy to realize the benefit of more frequent testing, thus increasing responsiveness, and obviously greatly reducing travel costs and vehicle emissions.
For a typical PM visit, the vehicle used to travel to site would be a small truck. For a conservative calculation we can assume the truck would travel approximately 50 miles round trip to conduct the monthly preventive maintenance. Using a battery monitoring system it is easy to assume that the number of truck rolls could be reduced to ¼ of those necessary when no battery monitoring system is used. If we only eliminate 3 truck rolls per year, the resulting reduction in CO2 footprint would be between 300 to 350 pounds annually per site visited. Realistically, many more site visits are typically required to address suspect or fault conditions, and battery support technicians are often dispatched to a site to examine the status of the battery — a battery monitoring system significantly reduces these trips as well. While this seems small, if you have many remote locations or the travel is longer, you can expect reductions to exceed several times the conservative estimate cited above. Total potential immediate savings per site could amount to well over 500 to 1,000 pounds of CO2 for a battery installation being monitored by a 3rd party maintenance organization.
Reduce waste – don’t arbitrarily replace
Another significant environmental benefit of using a battery monitoring system is the value of battery life extension. Without a battery monitoring system indiscriminate battery replacements take place often earlier than required. In many critical environments, there are planned VRLA battery replacements every 3 to 5 years — even though in some cases all batteries may be good, just to be safe, all jars in the battery are removed and new jars are installed.
Just imagine if we were such a wasteful society that we bought new cars from the dealership, drove them for three years, and then as standard practice, dropped them off at the junkyard where they were recycled into various products, at significant energy and environmental costs. You would not even consider this as a viable alternative to what we do today — we maintain the car, replacing selective components to get the maximum life we can — putting off the inevitable day when we scrap and recycle it.
This common sense practice should apply to batteries as well. We must move away from the idea that we should take a 10 year life battery and run it for only 3 to 5 years and then scrap the entire battery. Today, many companies carry out periodic maintenance and quietly accept that the information is useful in determining battery life. The reality is that without a battery monitoring system it is difficult to fully understand the health of the battery. With a daily battery monitoring system, you have the vital information needed so only the bad jars (monoblocs) are replaced as needed, extending overall battery life and maximizing the financial return on investment.
A model can help illustrate the monetary impact of extended battery life. Figure 1 below shows the total quantity of jars used for a 4 string battery with 40 cells per string over a 12 year period. The comparison illustrates this battery application model for a typical 5 year versus a 7 year battery replacement cycle.
Based on industry data some failures are projected to occur over the life of the battery and these are modeled with increasing probability of failure year over year.
It should be noted that the difference between these two columns is the true life cycle difference realized when a battery monitoring system is installed and used to extend the life of the battery system. It is straightforward that using fewer jars will ensure fewer jars will need to be recycled.
Figure 2 below illustrates the benefit of total batteries disposed to reclamation over the sample period.
In this model 121 fewer batteries were recycled over a 12 year period. That means over 12 years, approximately 40% fewer batteries will need to be recycled. Greater savings can be realized for every month the battery life can be extended.
Depending on the length of battery life and the number of battery failures, data center managers can expect to recycle a minimum of 13% fewer batteries. It is also realistic to expect some deployments where these savings will exceed 40% or more. There is a clear correlation between extending battery life and fewer replacement batteries and recycled jars.
While many components of lead acid batteries are recyclable they are not 100% recyclable. Fortunately, almost all of the lead plates and plastic casings are recycled. However, according to engineering consultant and solution provider Gravita Exim Ltd, while over 98% of the lead in a battery is recycled, of the total weight of the used battery, only about 55%-62% of the total weight of scrap materials are recycled in the process. In addition to these recycling by-products, it is estimated that on average globally over 5% of all batteries are not recycled. Applying these factors to the model above and assuming the mass of each jar was 100 pounds. The total waste would be reduced by between 2.2 and 2.5 tons of battery recycling residuals by extending the life of the battery by 2 additional years.
Right size your battery
There is another practice that results in a tremendous number of recycled jars. Some data center operators use more battery strings than required to provide their power protection — sometimes there will be as much as 2 times the UPS capacity requirement and thus 2 times the battery capacity needed. This is done with the hope that more battery strings can provide additional insurance against potential outages. The issue with this practice is three-fold:
- Waste of energy to charge unnecessary strings
- Waste of batteries that are truly not needed
- Without a battery monitoring system battery life is not maximized
A better alternative would be to use the number of batteries required including N+1 protection and adding a daily battery monitoring system. Any practice above N+1 is increasing recycling waste and is not providing any greater protection. All three of the issues noted above will be eliminated by exercising this practice.
While the most important and significant benefit of an intelligent battery monitoring system is the prevention of unplanned downtime due to battery failure, battery monitoring systems also play a major role in lessening the environmental impact of the increasing data center landscape.
Nearly every organization today has an environmental program in place. Now they can rely on a battery monitoring system to reinforce their commitment to protect resources and reduce waste.