The annual power bill is a large part of an operator's costs. Ulf Ewaldsson explains how to achieve efficiencies. Co-sponsored feature: Ericsson

 
 




Ulf Ewaldsson: the total electricity bill to run network equipment
over its lifetime is higher than the cost of equipment 

 
 


Radio networks have cut the energy they use every year per
subscriber from 80 kilowatt hours to a fraction of that figure,
and networks could be run as low as 1 kWh per subscriber
per year soon 


 Ulf Ewaldsson is an enthusiast about the telecoms industry’s need to reduce its carbon footprint — not just because doing that will be good for the environment because he knows he can help his customers in the industry reduce their energy bills.
Ewaldsson heads Ericsson’s radio access network business and he’s only too aware that the section of the mobile network that he supplies is responsible for most of operators’ energy bills.
“It is on the top of the agenda for network operators,” says Ewaldsson, a vice president in Ericsson. “The network consumes more than 80% of a mobile operator’s energy and two-thirds to three-quarters of that is for the RAN.”
How important is the energy used by the network to the world’s carbon footprint? Ewaldsson provides some figures to show that it’s actually quite small: of the whole CO2 footprint from human activity, information and communications technology accounts for just 2%, of which approximately 10% comes from mobile infrastructure.
So the mobile infrastructure made by Ericsson and its rivals accounts for about 0.2% of the human carbon footprint. Small in global terms, but significant for network operators — they pay the electricity bills.


Electricity per subscriber per year

And that’s where we find the numbers that will interest the CEO and CFO of a mobile network operator. Ewaldsson calculates a mobile network’s energy efficiency in a realistic way: kilowatt hours per subscriber per year.
A kilowatt hour — kWh — is what your domestic electricity meter measures. One 100-watt light bulb burning for 10 hours consumes precisely 1 kWh. The cost is on your electricity bill — in the US, the average cost of domestic electricity in April 2009 was 12 cents a kilowatt hour according to the Department of Energy.
When the mobile industry began, back in the mid 1990s, a network operator consumed an average of 60-80 kWh each year for every subscriber.
If networks were still using energy at that rate, a service provider would be paying up to $10 a year per customer just on the electricity bill to keep the network running. That’s at average US rates: in many parts of the world electricity is much more expensive. Multiply that by 10 million for an average network operator and you get an electricity bill of $100 million or so a year.
Here’s another shocking figure that every CTO or COO should show to their CFO to demonstrate how important energy efficiency is. “Add up the electricity bill of telecoms equipment over its lifetime and the accumulated cost is higher than the cost of equipment,” says Ewaldsson.
In other words, if you’re buying €1 million worth of network equipment from Ericsson — or from any other equipment maker — you’ll over a 10 year period spend more than €1 million to your electricity company to keep it going.
• Fortunately the costs are coming down — thanks to improvements in the efficiency of networks. “We’re getting close to 3-5 kWh per subscriber per year now,” says Ewaldsson. “We have more efficient hardware e.g more efficient power amplifiers in the transmitters, and we have a full set of network features that can improve the energy efficiency significantly e.g Dynamic shut-down of RBS components adapting to traffic demand”.


Measuring efficiency

He compares this kilowatt hour rating to the normal way drivers rate their cars’ fuel efficiency — in kilometres travelled for every litre, or miles per gallon in the US and UK. It’s a term every driver understands, “and everyone in the car industry talks about miles per gallon. The industry needs this simple way to refer to efficiency.”
In the telecoms business, this network efficiency number means an operator to translate the number of subscribers into the annual electricity bill. “It’s a clear measure. And the result relates directly to the overall operational expense per user and the average revenue per user.
Here’s another comparison, says Ewaldsson. “One year of carbon footprint for a subscriber is equivalent to the carbon footprint for one hour of driving a car.”
But how can mobile operators and their network equipment providers reduce the use of electricity still further, driving it down to 3 kWh per subscriber each year and ultimately to 1 kWh or less?
We’ve drastically improved the efficiency of many parts in the base stations, such as the power supplies, which now is already operating at more than 90% efficiency.” he says. There are still a few percentage points more to be gained by HW improvements but this does not compare with doing something smarter with the software and the signalling. As an example , take the increase in speed for 3G services. “Now we are increasing HSPA+ speeds from 21 megabits a second to 42,” says Ewaldsson. “Twice the speed can be translated into supporting the double amount of subscribers in the network ” i.e. reducing energy consumption per subscriber significantly.”



Double the capacity

“As mentioned we can double the capacity of a network with a software upgrade,” he says.
There are other software developments that increase energy efficiency. At one stage, a base station was either on or off, with nothing in between. “About two years ago we introduced software that shut down every part of a base station that is not in use.”
These improvements can be made to already installed base stations, he notes. “The software implementation is the first step. Upgrading the installed base so that it runs on more efficiently is the most important contribution you can make to efficiency.” Our BTS power saving software, for example, has exhibited power savings of more than 10 % in live networks.

Such savings are particularly important for operators that are not connected to an electricity grid. In many parts of the world “the most popular fuel supply for a mobile network is diesel”, says Ewaldsson. But that need not be as environmentally stressful is it sounds — because “we have a special system to reduce the use of diesel”, he says. “We call it a hybrid generator solution and potentially it can save more than 30% compared to a normal diesel generated site.

Solar and wind power

What about solar and wind power?
Alternative energies such as solar and wind, will also be one important factor in helping to bring remote, off-grid areas "on-line" and in bridging the digital divide.
They can both make a contribution in energy efficiency for for small to medium sized radio base station sites. Ericsson first started working with solar sites in 1983, and we have seen enormous technical and economic efficiency gains in this area over the years.
 
 
Driving down cost

That’s what the network equipment makers and operators can do, driving down energy use to one kilowatt hour per subscriber per year in time. When will Ericsson get there? “We have a vision where the majority of networks can run on single digit kWh per subscriber and year,” says Ewaldsson. “Yet it will take a couple of years to get there.”
But he has some further figures that should be of interest to all in the mobile communications business — though network operators can’t affect them directly.
If a phone network uses 3-5 kWh per customer now, what does that compare with the rest of the broadband communications ecosystem? A desktop computer in the home uses about over 200 kWh a year, he says, and a wireless router close to 50 kWh. And a plasma TV? Many models consume over 400 kWh a year.
But they’re not things that a network operator can control — and it’s the network operator that has to pay the fuel bill to keep its base stations running. It’s no comfort to the CFO, looking for business efficiency, that other people are paying higher bills for something else. As mobile services become more and more competitive, the energy bill will become a priority. GTB


To learn more visit www.ericsson.com