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The power equation: No factor too small or too big

Mon, 08/20/2012 - 2:01pm
Brian Santo

Going green is only one of many very good business reasons to find as many ways to save power as possible.

The electronics industry as a whole has been working on ways to save energy for years, but there are plenty of ways to save much, much more. Ongoing efforts are now involving everything from increasing the efficiency of products as basic as power supplies, to improving chip design for telecom equipment, to a nascent effort to define a means to manage the energy consumption of every element of entire communications networks.

Nationally, U.S. power consumption has recently tailed off, and at the same time, total power-generating capacity has actually declined. Both of those trends are statistical hiccups. Demand is certain to resume growing, and more facilities are expected to be built to meet that growth. The Edison Electric Institute estimates that through 2022, its member utilities will be involved in more than 100 projects, beefing up the grid at a cost of at least $64 billion, following the $77 billion spent in the last 10 years.

Telecommunications networks already consume tremendous amounts of power. If the consequences of higher energy consumption were only financial, the entire electronics industry would feel compelled to find ways to save energy (as it has been doing). But the ramifications of growing energy consumption for the telecommunications industry are far more serious.

Headends and central offices continue to bump against space restrictions, often a shorthand reference that elides the actual problem. Many headends have plenty of physical space left to fill; what they frequently can’t do is cope with any additional heat generated by additional equipment as it draws and dissipates power.

New communications services, notably cloud-based services, are going to draw even more power. And even if the utility industry is in the process of building generating plants and transmission facilities, there are no guarantees that sufficient capacity will be built where it’s needed, or come online when it’s needed.

Insufficient capacity is already an issue. Dan Cooper, a vice president at Time Warner Cable and chair of the SCTE’s Sustainability Management Subcommittee (SMS), said in a recent SCTE conference call that some MSOs are concerned that “in some cases, we just won’t have enough power potentially to expand and run our business in certain areas the power companies don’t have capacity, and that becomes an inhibitor to launching new business. It’s not just that we’ll pay a little more and our services will cost a little more.” Under those circumstances, the new launches “just won’t happen,” he said.

Many markets have had to deal with occasional, deliberately implemented rolling brownouts for years. And now the telecom industry is coming to the view that massive power outages resulting from a sequence of uncommonly severe natural disasters is the new normal. The response is a desire to be able to manage not just the traffic on a network, but also the whole network’s power consumption.

Last (and, in fact, least), there is a desire to meet consumer demand to be more green. Not that the people evaluating the problem are not philosophically in tune with green ideology – many are quite keenly green – but even they say that’s not one of the main goals.

“This is not about being green – if that gets factored in, that’s great – but it’s about reducing business risk in the coming years,” noted Comcast senior vice president of engineering for advanced products Rick Gasloli, speaking during the same conference call as Cooper.

“This is really a hardcore business thing for us,” agreed SCTE CTO Daniel Howard.

Back to basics
Late last year, Alpha Technologies introduced a new cable UPS (uninterruptible power supply) that incorporates a new transformer design. Coupled with “much tighter” output window regulation, the company’s new XM3-HP CableUPS will consume less utility power, translating into direct savings in network operating expenses.

Alpha promises that operators will save literally millions of dollars over the life of the equipment, more for customers with large numbers of power installations and/or that are doing a lot of business in regions with high energy costs.

The XM3-HP, which can be equipped with a DOCSIS transponder, generates real-time information on its own operating parameters, including the status of its battery, which users can tap to monitor its performance.

Eltek Valere's 48V rectifierCarrier networks rely on DC power. Eltek Valere has been improving the efficiency of its 48-volt rectifiers to the point where AC-to-DC conversion efficiency is typically 90 to 91 percent, with top-of-the-line models reaching 93 to 94 percent.

The difference of a few percentage points can be huge to a large power user. Eltek posits a typical power system that needs to deliver 8,000 watts of 48-volt power at a site. Using 90 percent efficient rectifiers, a DC power system must draw 8,889 watts of AC input power because it will end up losing 889 watts in the form of heat.

The use of 96 percent efficient rectifiers, however, will require only 8,333 watts of input power, with only 333 watts of power loss. Annually, the use of the more efficient rectifier will save 4,876 kWh. At $0.10 per kWh, that results in about $487 of savings per year for that single system. Now multiply that by the number of sites; a company the size of AT&T or Verizon could potentially save tens of millions of dollars a year, Eltek calculates, while significantly reducing its carbon footprint – no small issue in markets where excessive carbon emission can lead to financial penalties.

Chips with that
Saving energy starts at the fundamental level of silicon. Some power savings come as a natural consequence of integration. The same or similar design implemented in the next generation of smaller design rules will naturally draw less power.

That and other measures have helped lower the amount of power consumed by all sorts of communications equipment, from CMTSs to DVRs. The original DVRs introduced a decade ago drew well over 40 watts; today’s DVRs draw under 30 watts (DTAs draw as little as 4 watts).

FPGA vendors are making the case that communications system manufacturers should consider the use of FPGAs (field-programmable gate arrays) because they enable the integration of multiple functions in a single die, reducing chip count and thus reducing overall power consumption.

For example, designers can now integrate the RF combiner and RF up-converter external to a CMTS or edge QAM into a single chip, according to Xilinx.

Another FPGA vendor, Altera, has developed a design approach it calls Programmable Power Technology, which allows individual logic array blocks (LABs), memory and digital signal processing (DSP) blocks to selectively turn on power savings based on specific design requirements. The company expects the innovation will be useful for controller chips used in routers and other IP equipment.

Light sleepers
Network systems can be more power efficient, but so can customer premises equipment (CPE). Six of the largest MSOs last year pledged to introduce digital set-top boxes featuring an energy-saving light sleep mode by this September. At least one of them has already begun deploying them.

DVRs originally ran at full power all day, even when they weren’t being used. In 2011, the Natural Resource Defense Council did some investigating and calculated that all of the CPE associated with the average whole-home DVR setup drew more power than the average refrigerator in 2010.

NRDC chart
Everyone, including the cable industry, agreed that DVRs would be a great place to reduce energy consumption in the home. The result was the development of the concept of a light sleep mode, in which the DVR would suspend some operations, such as channel tuning and video display, when the unit is not in use.

CableLabs’s new Energy Lab, which oversaw the application of the concept, projects that the new DVRs will offer energy savings of 20 percent or more. The organization estimates that as many as 10 million units could be in the field by the end of this year.

Estimated national power consumption
The Energy Lab itself is a new project that embodies the green ethos in the cable industry. The operation is working to design and maintain a consistent and accurate energy-tracking program for measuring and reporting energy consumption of new set-top boxes, and it serves as a testing and development facility for designers of energy-efficient software and hardware, among other energy-saving goals.

Energy NOC
Reducing the amount of energy consumed by any individual item of equipment was always going to be only a start. The idea of a smart grid is more than a decade old; inherent in the notion is the ability to monitor and control not only energy production and transmission, but also consumption.

The SCTE’s Sustainability Management Subcommittee is plotting a series of standards and practices that will ultimately lead to MSOs gaining those capabilities, running what SCTE senior director of information technology and energy management programs Derek DiGiacomo referred to as “an energy NOC.”

In the SCTE conference call in May, Howard said: “DOCSIS just had the CMTS and cable modems and DHCP servers. Here we’re talking about anything and everything from encoders, QAM devices in hubs, edge devices, all the way up to servers and data centers, even up to building energy management systems and controls, tying this all into a disaster recovery scenario where you have to drastically alter your energy consumption so you can keep offering services for the longest amount of time.”

Last year, the subcommittee started by introducing drafts of its first two proposed standards, SMS 001 and SMS 002, the former recommending energy conservation, sustainability and efficiency practices, and the latter concerning environmental requirements for cable telecommunications facilities that addresses such considerations as temperature, humidity, electromagnetic interference and environmental design.

The subcommittee also began work on SMS 003, the development of an Adaptive Power Systems Interface Specification (APSIS) for hardware.

SCTE President Mark Dzuban said, “The fundamental APSIS program is looking to start to deploy in ’15 and ’16, the beginning of these control functions for energy, and then hopefully – not certain – we see software-driven upgrades after that.”

One element of the program likely to be implemented perhaps as early as next year will be predictive alarming: the ability to look at data and see parameters changing and respond appropriately.

Another element will be 3-D temperature modeling of facilities, Dzuban said.

“You can see the racks in it and everything else and use the standard color coding for temperature variance, where red is the hottest and blue is the coldest,” he said. “We know when your temperature increases by 10 degrees centigrade, your meantime between failure drops to half. We know hotspots in facilities cause potential failure modes in the longer term. We want to look at all parameters by which technology fails and have automated alarming that will tell us to take action.”

The ultimate goal, he said, is to put into place “all the control functions needed to manage a complex network in an automated form that allows for minimal human intervention, optimum performance, optimal capital investment and using technology to compete in the marketplace in a real differentiating way.”

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