The overwhelming majority of all broadband providers’ electric bills are for edge facilities and the access network itself.  It’s basically a numbers thing: with the exception of hyperscale data centers, a typical broadband service provider’s data center individually consumes a few megawatts of power while edge facilities like hubs and headends consume tens to hundreds of kilowatts.  There are hundreds or thousands of edge facilities vs. tens of data centers in the overall network, and also many more active devices in the access network itself. As a result, 73-83% of the operators’ total energy bill comes from the edge facilities and access network itself. 

Likewise, in both DSL and wireless access networks (and the largest telcos must typically power both of these access networks), providers spend the majority of their energy bill in the edge facilities and outside plant.

The Challenge: Legacy Facilities and Access Networks

When deploying new access networks or edge facilities, using modern PON technology and ASHRAE- and LEED-compliant energy efficient buildings is more energy efficient.  Edge facilities can be consolidated into a newer, larger facility that is designed with modern energy efficient practices; this is already being done by major cable operators as is reported in the SCTE’s Energy Management Subcommittee.  But newer and consolidated facilities still represent a fraction of total facilities.

According to a new SCTE operational practice developed by experts from Hitachi and others in the Energy Management Subcommittee (EMS) of the SCTE standards program, upgrades to legacy edge facilities can include:

• New equipment racks with airflow contained in hot aisle/cold aisle fashion that prevents mixing of supply and inlet air
• New computer room air conditioning (CRAC)/heating
• Ventilation and air conditioning (HVAC) units that use free-air cooling and/or economizers
• Variable-speed fan drives
• Modern intelligent energy monitoring and management that can take advantage of higher set points and optimized airflow
• Optimized power generation and distribution
• LED lighting
• Building envelope improvements to reduce leaks and solar loss
• Alternate energy and microgrid technologies like solar, fuel-cell, wind, and geothermal, to reduce the grid dependence and to provide a backup power source

Providers postpone these upgrades due to cost and customer impact. ROI can take years, sometimes many years like LED lighting in hubs, which are unmanned for the most part,.  For the rest, broadband network investments should pay for themselves in far less than five years due to the capital-intensive nature of network operations.  Consequently, financial schedules tend to put facility upgrades on the back burner, with new CRAC/HVAC units added when older units fail.

The situation is similar for outside plant.  Even though 90 V powering of the outside plant is more energy efficient than the older 60 V powering, there are still plenty of 60 V power supplies in networks.  Upgrading to 90 V supply would not only reduce Joule heating (also called I²R) losses in the coaxial cable via lower currents, but the most modern power supplies also include transponders and energy reporting/metering features so that cable operators are not overcharged for powering their outside plants and can centrally monitor energy consumption for better negotiations with local utilities.

Another SCTE standard, ANSI/SCTE 212 2015 provides a framework for doing audits of power consumption in edge facilities and in the outside plant, for just this purpose. It’s already reduced the electricity bill for operators like Cox, who helped author the standard.  With detailed knowledge of actual consumption, cable operators can negotiate for lower bills and determine if power supplies are right-sized and optimal for power efficiency.  

For example, the 80 PLUS voluntary certification, which is now part of the Energy Star computer specification, “certifies products that have more than 80% energy efficiency at 20%, 50% and 100% of rated load, and a power factor of 0.9 or greater at 100% load.”  An OSP power supply that is only 70% efficient and consumes 1 kW of mains power will waste 300 W of power as heat.  If there are 10,000 such units in the outside plant, this represents a total energy waste of 3 MW in the OSP which could cost operators several million dollars annually.