TECHNICAL
level RF outputs necessary for extended spectrum plant. A system already using DAA has probably already made a decision on next- generation HFC plant, so we will not analyse DAA power consumption further.
of maintenance. However, the largest difference in operating expense is in an area which may surprise you: powering the plant. HFC networks, old and new, require power to run the nodes and the amplifiers. Because these elements are located in the outside plant, a distributed power solution is required. Power supplies are distributed throughout the plant, with each serving a cluster of nodes and/ or amplifiers. In most cases, back-up batteries protect against outages in the commercial power source. These batteries have a finite life and require periodic replacement. In contrast, PONs are by definition “passive”. An Optical Line Terminal (OLT) located in a central office or headend feeds the fibre plant. There are no amplifiers or other electronics in the plant, so there is nothing to power. When adding PON as an overlay network to eventually replace an existing HFC network, it is desirable to make as much use of the installed fibre as possible. Installed spare fibre counts are probably far short of what is required for a PON. A remote OLT (ROLT) solution can serve to multiply these fibres to provide PON service without large-count extensions. In this case, power in the field will be required. How does that power requirement impact the savings of PON versus HFC? Let us quantify the power used for HFC networks, and see what could be saved if the same plant geography was instead served by a fibre-based PON network.
Amplifiers
Line extender amplifiers, along with mini-bridger amplifiers are exclusively used in short-cascade HFC plant, while older plant uses a combination of trunk amplifiers (with built-in bridger amps) and line extenders. For each of the trunk amps, we can expect 80 to 120 watts, and for the line extenders or mini-bridgers 35 to 50 watts.
What does electricity cost? US, Europe, Africa, LATAM
1. United States
Electricity costs can vary tremendously from state to state. Below, we list the average price for residential service per kilowatt hour. Commercial prices should be similar. Most Expensive States $ / kWh Hawaii $0.30 Connecticut $0.24 Alaska $0.23 Rhode Island $0.22 Massachusetts $0.22 California $0.21 Vermont $0.20 Least Expensive States $ / kWh Kentucky $0.11 Utah $0.11 Missouri $0.11 Oklahoma $0.11 Mississippi $0.11 Arkansas $0.11 Tennessee $0.11 Idaho $0.10 Washington $0.10 Louisiana $0.10
BASIC ASSUMPTIONS
What power does a node or amplifier use?
The first bit of information we will need is an estimate of the power used by various HFC plant elements.
Nodes
A look at the most popular 2x2 (two service groups) and 4x4 (four service group) analogue nodes shows that each consumes between 80 and 120 watts. Next-generation distributed access architecture (DAA) nodes consume at least this much. Not because the electronics are less efficient, but because new nodes frequently include the high-
Source: September 2020 – GPP- ©Statista 2021
The US average is $0.15 per KWh.
MARCH 2025 Volume 47 No.1
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