Anyone who has followed the international phenomenon known as the Apple iPhone knows that today’s telecom carriers are under greater pressure to expand existing infrastructure in order to support bandwidth-intensive data and video services that are in high demand. But carriers are also facing pressure from governmental agencies, environmental activists, consumers, and their own board members to reduce energy consumption, for a variety of reasons. This raises an important question: how can today’s carriers implement the infrastructure upgrades needed to meet subscriber demand, while keeping energy consumption rates and cooling costs low?

A holistic Total Efficiency philosophy may be the key to achieving both. Total Efficiency addresses all of the network’s locations, end-to-end -- central offices, mobile switching centers, cell sites and data centers -- as well as all of the components, including AC-DC power supplies, DC-DC board mounted power, and DC energy system rectifiers. When implemented properly, the Total Efficiency approach enables and protects voice/video/data applications and services while reducing energy loss and lowering cooling costs. (See Figure 1.)

Figure 1. The holistic approach to energy efficiency takes all layers of the telecommunications infrastructure into account.

The DC Energy Advantage
Data centers still relying on AC UPS systems are not only inefficient, they are actually responsible for significant losses in energy conversion. It’s widely accepted today that 48V DC is the standard that’s validated by The Green Grid as the most efficient, end-to-end architecture. The IEEE Power Electronics Society has also stated that 48V DC traditional telecom systems with batteries and generator sets are 20 times more available than AC UPS systems.1 Small 48V DC telecom systems with 8 hours of batteries are orders of magnitude more available than the average AC UPS system. (See Figure 2.)

Figure 2. The Green Grid has validated 48DC as the most efficient choice for end-to-end architecture efficiency.

A best practice, Total Efficiency telecom architecture should take an end-to-end view:
• AC/DC front-end for telephony, computing, storage, and networking devices.
• DC/DC board mounted power for attached devices.
• DC energy systems for carriers and large enterprises.

One example of a Total Efficiency DC/DC board mounted power solution is the patented Tunable Loop™ technology. Tunable Loop solutions achieve increased density, improved response, reduced capacitance, and increased reliability at a lower cost to equipment manufacturers. The next-generation, low-profile packaging also allows power components to be placed on the back of circuit boards to enable communications, computing, and storage vendors to deliver more capable systems in smaller sizes.

Total Efficiency vs. Legacy: Staying the Course Is Costly
There are three common telecom power infrastructures:

1. Centralized Architecture places power conversion and batteries in a separate room, away from all the datacom and telecom gear, with cables from the battery room to the racks where gear is installed. The idea with this scenario is to lower risk and improve safety by protecting network equipment and minimizing failure.

2. Distributed Architecture puts the power equipment in the same rack as the datacom or telecom gear. Obviously, the drawback to this infrastructure scenario is the lead acid of these energy systems being placed in such close range to $500,000 industrial routers.

3. Hybrid Distributed Architecture, which is the architecture we recommend, preserves existing battery room investments and avoids costs of re-cabling the infrastructure while still placing rectifiers in a top of rack or end of row configuration -- an estimated 50 percent annual savings by reducing distribution loss. This is a design where the lead acid batteries are left in the battery room and then only the rectifiers are placed near the datacom and telecom gear. (See Figure 3.)

Figure 3. A sustainable source architecture prioritizes clean and green energy sources before generators or the utility grid.

Make no mistake: the large data centers required to keep subscribers’ telephones ringing are massive consumers of energy; some reports have this rate at 2 percent of the planet’s entire electricity supply. The average energy bill for a Fortune 100 telecom’s data center is a whopping $10 Million per month. Furthermore, these large carriers are currently spending in the range of $1 Billion per year solely on cooling costs for these centers.

Forward-thinking carriers are beginning to understand that the cost of staying the course with legacy energy systems is becoming increasingly more prohibitive than investing in new Total Efficiency systems. It’s about much more than being able to tout that you run a Green telecom organization: it’s about saving millions of lost dollars that could be re-appropriated toward expanding infrastructure and keeping consumers satisfied.

A best-practice Total Efficiency architecture addresses issues across the spectrum of the telecom architecture to deliver a solution that is safe, reliable, and energy-efficient. The best Total Efficiency products are those that, by design, foster investment in alternative energy by prioritizing the use of sustainable energy sources like solar, wind, water, and fuel cells over traditional utility grid or diesel generator sources. These products intelligently respond to smart grid information to reduce consumption during peak demand periods.

The ideal system should:
• Disconnect from utility grid during peak demand periods.
• Include automation features via utility communications protocol.
• Be dynamic based on lowest cost of power.
• Intelligently schedule based on peak load hours.
• Deliver an average conversion efficiency approaching 97%.

Status quo can no longer be the default, acceptable business practice for running large data centers. We have all come to learn that energy is not an inexhaustible resource, and that the cumulative effect of wasting power taxes both operational expenses and our energy grid.

Smarter, more efficient means of power conversion are currently available and should be immediately utilized. Smarter power conversion needs to be augmented with renewable energy sources whenever possible to help ensure a smooth distribution of energy throughout the national grid.

Endnote: 1. Powering the Internet: Datacom Equipment in Telecom Facilities: The Need for a DC Powering Option, Technical Subgroup on Telecommunications Energy Systems of the Power Electronics, Society of the Institute of Electrical and Electronics Engineers, Inc., 1998.

About the Author
Vito Savino is the director of Product Management for Lineage Power, a provider of intelligent power conversion systems. Savino welcomes your thoughts at vito.savino@lineagepower.com. Lineage Power delivers intelligent power conversion solutions. For more information, visit www.lineagepower.com.

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