Insight and analysis on the data center space from industry thought leaders.

Data Center Energy Efficiency Through BCM

With economic events intensifying the need for a change in the way power is billed, branch circuit monitoring (BCM) is becoming a benchmark to help both customers and colocation providers face some of their biggest power monitoring challenges.

Industry Perspectives

January 22, 2010

8 Min Read
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David Dunn is Senior Vice President of Marketing and Business Development for CoreSite, which operates more than two million square feet of wholesale data center and colocation space.



It happens each month to everyone who owns a home. Within the pile of invoices, letters, coupons and credit card offers that arrive in the mailbox, you find a utility bill that details the amount of electricity you consumed the previous month and the price for that electricity. You might very likely look at the bill and make a resolution to reduce your power consumption to save cash, while simultaneously reducing your carbon footprint. A noble initiative indeed!

What if your bill not only excluded the amount of power consumed, but showed the same amount owed, month after month, regardless of use? Would you run your furnace or air conditioner less? Would you turn your computer off when not in use, unplug unused appliances, or buy more expensive energy-efficient lights? Probably not, because without information there would be no incentive to consume less.

Now project this situation into the billing cycles of large companies. Just as with a family home, when a company’s energy usage is not transparent and the amount of money paid each month is the same no matter what is used, millions of dollars and millions of kilowatt-hours are wasted. The problem is the same, but there is a difference of several meaningful decimal places between a residential utility bill and a major company’s data center utility bill.

Believe it or not, this nightmare billing scenario happens to companies of all sizes at many of today’s colocation facilities. It’s even worse for in-house data centers, where you might not even see, let alone be responsible for, your data center utility bill.

How did the colocation industry come to bill power so nebulously?

Lack of Individual Usage Information
The cardinal rule to keep in mind when managing a data center is that power (for both IT and mechanical loads) is a finite resource. You have to restrict usage to the amount of available power. Colocation providers have understood this since the inception of the industry, and that’s why they design electrical and mechanical distribution systems around the total amount of power available (the minimum amount of power available from the utility company or the level of a generator’s capacity).

Historically, colocation providers simply have not had a means to monitor each customer’s individual power usage to help them stay within the capacity of the power sources. They couldn’t provide customers with a summary of their electrical usage, let alone provide an incentive to reduce electrical consumption. Because they could not tell exactly how much power each customer was using, colocation providers developed pricing models that resulted in fixed power fees based on provisioned power instead of usage.

A fixed price for power per breakered-amp was largely set at a level designed to cover the direct utility cost for the circuit’s power draw, plus the electricity required to cool the heat produced by the IT equipment. Because colocation providers lacked information and wanted to be sure to cover their costs, they set the breakered-amp price at an approximate level that assumed each customer would fully utilize each power circuit. Companies ended up paying for power they didn’t use, and at no point did they understand how much power they were actually consuming.

It’s not that colocation customers haven’t wanted to save money or consume less power. They have always sought ways to get the most mileage from technical deployments. Data center power bills can be upwards of 30%-50% of total deployment cost, so power is an obvious target for cost-cutting initiatives.

BCM Provides New Costing Model
With economic events intensifying the need for a change in the way power is billed, branch circuit monitoring (BCM), the newest technology for measuring data center power, is becoming a benchmark to help both customers and colocation providers face some of their biggest power monitoring challenges.

In its simplest form, BCM is a way to track actual usage of each power circuit, whether in a home, office or data center. Technically speaking, BCM is a system that uses current transformers (CTs) to measure the electrical current of each power circuit within an electrical panel or PDU. The BCM equipment used today has been engineered to integrate seamlessly with a wide variety of turnkey hardware and software packages used for gathering and storing circuit data. Alternatively, using open standards, it is possible to gather and store the data from a BCM circuit board using custom software and hardware. In either case, once the readings have been gathered and stored, they can be analyzed, ported, retrieved or transferred as easily as any other piece of data.

BCM originally was implemented as an easy way to see electrical usage on each panel at a glance. Engineers and operators could know when physically looking at electrical panels if there were any circuits in danger of tripping or if there were any tripped breakers (indicated by zero current). As the technology progressed, BCM was used to trigger simple alarms for local or remote personnel charged with monitoring the health of the electrical distribution system, which resulted in higher facility uptime. Though these uptime-maximizing functions of BCM have become more robust in recent years and are one of the most important features of the technology, BCM also has opened new doors for customer-facing transparency.

Measuring Actual Usage
Perhaps the most profound application of the modern BCM system within the colocation facility is the ability to measure the actual usage of each power circuit as a means of calculating power fees. Now, not only can a colocation provider offer insight into actual usage, but the provider can help customers save money by identifying opportunities to reduce consumption. To accurately accomplish this, a BCM system must have a few key elements in place.

The first requirement is a location to record and store the data supplied by the CTs within the electrical panel. As it stands today, relational databases such as SQL are used commonly as the preferred storage method for the CT measurements. A second reference table or database that defines each circuit is also required. This element of the BCM system must define the panel/PDU, circuit voltage, breaker positions within the panel (for 208V or 3-phase power), and the appropriate circuit user (the customer).

The CT’s historical data and reference table makes it possible to generate a usage trend of each circuit, along with the ability to reference that circuit back to a specific customer. If a colocation provider can summarize power consumption in customer bills or through an online portal, customers can see usage trends and reap the benefits of energy conservation through virtualization, smart power management, or simply by identifying and shutting off underutilized servers. Different departments within a single data center deployment could also verify individual power usage for more accurate cost accounting.

Though usage-based power pricing is primarily a boon to colocation customers, the BCM system also offers a number of meaningful benefits to colocation providers.

As we all have witnessed in the past several years, energy prices are anything but stable, and the fees from a utility company often reflect this volatility. Employing a usage-based pricing model allows colocation providers to immediately pass along any cost changes directly to customers nearly real time without the need to manually notify customers and adjust billing - often the case in fixed pricing scenarios.

Usage trending is another benefit BCM systems offer to colocation providers. A database of circuit data allows for the analysis of trends on circuit, panel or UPS usage to help predict future demand. Depending on the level of detail maintained in the reference database, it also might be possible to analyze power based on equipment type, market segment, geography and more.

Time for a Change
In the past, fixed power pricing made logical operational and business sense. Without the ability to measure and collect data on individual circuit use, it was impossible to see actual use below the UPS units (electronics on UPS units show usage). Fixed pricing still makes sense where BCM technology is not installed or for small customers. For smaller deployments, the cost of monitoring and billing relatively low power draws exceeds the benefits of transparency. On the other hand, for very large data users, monitoring consumption at the electrical panel or UPS level may make more operational or fiscal sense.

The impact of the change from fixed to usage-based power pricing varies greatly from customer to customer, depending on their unique usage profile. At the very least, access to data on actual power usage can lead to benchmarking and, hopefully, eventual reduction. If companies can reduce their bills through reduced usage, then they have an incentive to reduce power consumption, which is good for everybody. For some companies whose power consumption periodically varies (seasonal usage, holiday peaks, etc.), the benefits of usage-based power pricing can be even greater. These companies can reduce costs during non-peak periods compared to fixed pricing models. Other types of users that have low usage/high breakered-amp profiles, such as network operators, could also stand to benefit greatly. These customers are paying a relatively high fixed power price for little power use.

Power is the primary resource in a data center, and its availability and emissions are a growing concern. As the effects of climate change gain more attention in the national media and result in potential government regulation and oversight (as in H.R.2454), knowing not only how much power you consume, but also the generation mix of consumed power (to specifically understand carbon usage) will become increasingly important, if not a requirement. Further, you can get ahead of the curve by setting targets for future reduction. Implementing BCM in your own data center or asking your colocation provider to implement BCM technology and usage-based power pricing, is one way your company can help reduce long-term carbon emissions and save money.

Industry Perspectives is a content channel at Data Center Knowledge highlighting thought leadership in the data center arena. See our guidelines and submission process for information on participating. View previously published Industry Perspectives in our Knowledge Library.

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