Recently, Vodafone Germany's boss is quoted (in Germany) saying that Vodafone Germany currently spends a middle three digit million sum a year on power for its mobile networks in Germany. Interesting, so let's break that number down a bit.
Let's assume that Vodafone's yearly power bill for their complete GSM and UMTS networks is 400 million euros and that their DSL assets are not included. I am not certain of the later one but there's no telling if that is the case or not and how much power their DSL lines use. Let's further speculate that around 25 million people in Germany are using their network today (not SIM cards!). 400 million euros / 12 months / 25 million people = 1.3 euros per person per month.
I'd say their revenue per person (i.e. not ARPU per SIM card) is around 15 euros, which is probably on the conservative side. So around 8-10% of that is spent on power.
At a rate of 0.2 euros per kW/h, that means I 'personally' use about 6.5 kWh of power a month for mobile telephony and mobile Internet access. An interesting number, that is a bit higher than the 1.4 kWh that resulted from a calculation in this previous post. In the previous post however, a global average was given which did not take into account that in most European countries, most network operators have both a GSM and a UMTS network, thus doubling power consumption compared to countries which only have GSM networks. Also, networks are much more heavily used per person in industrialized countries, which again increases the power consumption per person as more base stations are required. For the total power use for my mobile activities one has to of course also add the power for recharging the mobile phone and to a certain extent also the power consumption of my notebook.
It would be an interesting comparison how much power is required for my fixed line DSL and telephony connection at home and in the office. The DSL modem / Wifi access point / DECT phone setup (let's say this is my private fixed line mini base station) consumes at least 15 watts, which amounts to 15 watts * 24 hours * 30 days = 10 kWh a month. In this number, the power requirements of the network behind is not yet included.
While not directly comparable, each of those numbers give an interesting insight into how much power is required per person to drive our information society. Compared to the several hundreds of kwh of power per month consumed per person in Europe, however, the number is not negligible but still quite small.
Power consumption savings seems to be high on vendor’s roadmaps this year. One solution on the 2G side seems to be to shut down transceivers (typically GSM cells have more than one) during times of low traffic (e.g late at night). The process is fully automated and once the network detects network load is increasing it turns on the additional transceivers again. For 3G, this is not that applicable at the moment, as most operators have single carrier sites.
Thanks for the excellent blog and Happy New Year!
Hello Mark,
A good new year 2009 for you, too and thanks for all your insightful comments over time!
I wonder how power saving could work out with 3G, most emphasis is on GSM for the moment. As 3G grows and more than one carrier is used the second one can be shut down when there is little demand, e.g. over night. Apart from that I guess that there is a kind of automatic power saving when the cell is not used, i.e. no power to DCH’s assigned and the HS-DSCCH’s are not transmitting any data, i.e. no power is used for them, too. Let’s see what vendors are coming up with. I think reducing the power output is only one th. The digital processor cards might be another area of opportunity to save power, maybe in a similar way as on notebooks today by reducing the processor speed, or, in case of multi-processor technology, switch off some processing banks.
All the best,
Martin