T-Mobile Cell Site Now Powered by the Sun

T-Mobile is hoping the sun is shining down on one of its cell towers in Chalfont, Penn. That’s because the gear is T-Mobile’s first solar-powered cell site in the U.S., and enables T-Mobile to tap into the sun to power a selection of gear that provides wireless broadband services.

T-Mobile didn’t give more details on how much power the 12 solar panels attached to the site would generate, only saying the power was enough to take the cell site off-the-grid and then “at times” feed power back into the grid. T-Mobile can use the cell site for lowering its carbon footprint (and green marketing) as well as potentially saving on its energy bill, but savings on electricity costs via solar often times have a long pay back period. Solar can also be used as a backup power source for cells if power grid blackouts occur.

The T-Mobile solar-powered cell is somewhat unusual in that it wasn’t built in a developing country. Phone companies most often turn to solar-powered cells in countries like India, and parts of Africa, where the sites can be few and far between, and phone companies want to use solar to replace or augment diesel-powered back up generators (see our report How Mobile Networks Can Cut Carbon, GigaOM Pro, subscription required). According to Pike Research, 4.5 percent of the world’s cellular base stations will run off of solar and wind by 2014, up from 0.11 percent in 2010.

In certain developing regions, solar-powered base stations can be economical. Phone companies are increasingly factoring in diesel fuel costs over the life of the system compared to the free fuel that is solar. Mobile operators are also taking into account potential carbon legislation (that makes carbon-based power more expensive), as well as the likelihood that the cost of clean power will drop in the future. Connecting into the grid can also be quite expensive in certain regions: for example, it’s $8,000 per kilometer to connect into the grid in rural Namibia, according to Kuwait-based Mobile Telecommunications Co.

Chalfont is a small, several-thousand-person community, but well developed, so those typical developing-world economics aren’t likely at play for the U.S. solar cell site. Solar-powered cell sites generally cost two to three times more than grid power in many regions, according to the GigaOM Pro report. My guess is this first tower is mostly a way to test the technology and use it as a marketing tool. Phone companies have boosted their green efforts in recent months as a way to cut costs, and get some good PR.

But as we note in our How Mobile Networks Can Cut Carbon report: “the first, and most effective, strategy for reducing energy consumption in mobile networks is to improve the energy efficiency of network infrastructure equipment itself.” Base stations actually make up 70-to-80 percent of the energy consumption from cellular networks, so it’s really important to reduce their overall power draw, instead of just switching them over to clean power. Pike Research says that clean power technology, like solar and wind and fuel cells, combined with energy efficiency, could reduce the carbon emissions due to mobile infrastructure in 2013 by at least 101 million tons of carbon dioxide equivalent (MtCO2e), a decrease of 42 percent from business-as-usual trendlines.

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