Energy consumption of telecommunication access networks

6.3.3 Total power consumption HFC The total power consumption of the HFC access network and the customer premises equipment is shown in Figure 23. Depending on the service group size, the power consumption is between 464 kW and 671 kW. Service group size 16 32 64 128 256 512 Number of service groups 1,584 794 399 202 103 54 Power consumption amplifier points [W] 89,100 44,640 22,410 11,340 5,760 3,015 Power consumption central offices [W] 126,720 69,120 34,560 17,280 11,520 5,760 Total consumption of customer premises equipment [W] 455,598 Total power consumption HFC network [W] 671,418 569,358 512,568 484,218 472,878 464,373 Figure 23: Total power consumption of the HFC access network and the customer premises equipment. A typical current service group size is around 256 subscribers per service group. The ISP (Internet Service Provider) can provide the required 50 Mbit/s with DOCSIS 3.0 at a service group size of 256; even higher data rates are possible. However, the HFC access network is a shared medium, so all subscribers within the same service group share the available transmission capacity. If the data rate of 50 Mbit/s is to be a minimum data rate per subscriber, a service group size of 32 or fewer subscribers is needed. Otherwise, the 50 Mbit/s cannot be guaranteed to each subscriber. A service group size of 32 leads to a total power consumption for the HFC network of 569 kWor 4,987,576 kWh per year, which is approximately 2,663 tonnes of CO 2 . 6.4 FTTH – Point-to-Point and GPON As described in chapter 6, there were no active FTTH networks within the model region. Therefore, a green field approach was chosen. In addition, the FTTH technologies do not suffer from relevant length restrictions so that even long cable lines of several kilometres will be no restriction. 6.4.1 Point-to-Point access network To determine the power consumption of the access network, the number of PoPs to connect each subscriber has to be estimated. This calculation is a spatial analysis, which tries to maximise the number of subscribers per PoP. This calculation leads to the numbers shown in Figure 24. As can be seen there, 36 PoPs are needed in total. 21 of the 36 are PoPs of the maximum size. The other 15 PoPs are smaller ones. Therefore, approximately 82% of the subscribers can be reached from the biggest PoPs. An additional 10% of the subscribers are reached with PoPs of the size of 500 and 750 subscribers per PoP. 24