Mobile phones long ago began conquering parts of the world that are far away from the nearest electrical substation. But the rising price of oil is exposing a problem with the networks that connect mobile handsets together.
In the far reaches of places like India or Africa, where companies such as Ericsson (ERIC) or Nokia Siemens Networks, a joint venture of Nokia (NOK) and Siemens (SI), are installing new cellular base stations at a furious pace, the facilities almost always get their power from diesel-powered generators. But fuel can account for as much as two-thirds of base-station operating costs. Add to that the expense of trucking diesel over poor roads to far-flung locations and protecting the valuable fuel against theft. “Getting oil or diesel to these stations is tremendously difficult,” says Mats Granryd, president of Ericsson India.
As a result, green energy is suddenly becoming more than a feel-good project for the world’s mobile service providers. As mobile networks expand far beyond the reach of power grids, they need to find alternatives to diesel. After experimenting for years with base stations powered by wind, solar energy, or biofuel, equipment suppliers are preparing to roll out alternative energy technology in significant numbers.
“We’re starting to see this deployed globally now,” says Dawn Haig-Thomas, director of the development fund of the GSM Assn., an industry group. “It’s our hottest area.” Two Asian network operators will shortly announce plans for more than 500 new base stations powered by a combination of sun and wind, Haig-Thomas says. (She declines to name the operators.)
Solving the power problem is key to maintaining the growth of the mobile industry. The number of mobile subscribers is expected to climb to 5 billion by 2015, from 3 billion today. A large proportion of those new users will be in poor, rural areas with little infrastructure. Flexenclosure, a Swedish company that makes shelters to house base station equipment, estimates that in Africa alone 40,000 new base stations will be located beyond the reach of reliable electrical power during the next few years.
CHEAP, RELIABLE ENERGY
Thanks to advances in energy technology, it’s becoming more practical to run base stations with renewable sources. For example, it takes only one-fourth as many solar cells to power a base station as it did five years ago, according to a recent Ericsson study. Equipment producers also have put more effort into reducing the amount of power that a base station needs in the first place. In India, Ericsson buries the batteries for a base station 20 feet underground, reducing the need for energy-gulping cooling equipment (and also reducing the risk of theft).
Installing the radio equipment at the top of the tower next to the antenna also saves power—the shorter the cable connecting the radio to the antenna, the less power lost in transmission. Nokia Siemens also has worked on reducing power consumption with software that shuts down part of the base station at night when there is less demand. “This is a major area of competition: Who can come up with a base station that runs on the lowest amount of power?” says Haig-Thomas.
The goal is for base stations to generate their own juice. In the Indian state of Maharashtra, mobile-services provider Idea Cellular (IDEA.BO), working in conjunction with Ericsson and the GSM Assn., is running four base stations with a mix of diesel and locally produced biofuel. Currently the fuel is refined from waste cooking oil, but in a few years the biofuel may come from jatropha, a hardy oil-producing shrub grown by local farmers.
MIXING WIND AND SUN
Over at Nokia Siemens, engineers favor using wind and solar power in part because it generates no carbon dioxide. The drawback, however, is that few locations have reliable supplies of both sun and wind. Many regions of India get ample sunlight most of the year—but little during the monsoon season. So manufacturers are moving toward facilities that use both wind and sun. Flexenclosure recently unveiled a design for a base station that features a wind generator atop the same tower that supports the antenna. Solar panels sit on the roof of the shelter that houses the switching equipment.
The initial investment for such a base station is higher than that for one powered by diesel. (The actual cost varies widely according to location.) But wind- and sun-powered stations cost dramatically less to operate. And the cost is more predictable because network operators don’t have to worry about fluctuations in the price of oil. “Once you have them up and running, they need virtually no maintenance. You need someone to go wipe off the panels once in a while,” says Anne Larilahti, head of environmentally sustainable business at Nokia Siemens. “When you consider the total cost of ownership over five years, the business case starts to look very good.”
So good, in fact, that someday, green-powered mobile base stations could start to pop up even in developed countries where the power grid is ubiquitous and reliable but pressure is mounting to reduce carbon emissions. It’s the dawn of the green mobile network.