The telecommunications tower has become a ubiquitous part of the urban landscape. More towers go up as more people and mobile devices demand reliable, fast cellular and data service.
A telecom tower using Aquion batteries in China.
But some of the fastest-growing markets for wireless service are in places where the power grid is weak or nonexistent. Remote telecommunications towers need power, and extending the power grid is often prohibitively expensive. It’s an especially poor investment in regions where grid power is expensive or unreliable. What’s a telecom company to do?Go off-grid, of course.
More than a million telecom towers operate in off-grid or in bad-grid areas, and the numbers are projected to rise. More than 90 percent of these towers run off of 127 million barrels of diesel fuel per year. Burning that diesel releases roughly 40 million tons of CO2, or about 17 pounds per mobile device subscriber.
Not only is diesel dirty, it’s also costly. Diesel is the single largest expense in remote tower network costs, between 30 percent and 40 percent. Telecom companies have been trying to spend less on the fuel itself, on offsetting diesel theft, and on transporting diesel to out-of-the-way places. One strategy has been to outsource telecom tower energy ownership and management to more specialized companies. They, in turn, have been turning to hybrid renewable energy systems to decrease tower energy costs and increase their uptime reliability. These systems typically pair on-site solar power with energy storage batteries to run the tower at night or when it’s cloudy.
Certain markets are even mandating clean energy in telecom installations. India, for example, required half of rural towers and 20 percent of urban towers to be powered by renewable hybrid generation sources and grid power in 2015.
Telecom companies are willing to pay big bucks to go green. It means accessing 1.2 billion potential customers in developing regions without good grid power, such as sub-Saharan Africa and India. One analysis predicts that the telecom industry will spend annually $3.1 billion by 2024 on distributed generation and energy storage resources. The total spent will top $31 billion.
Solar-Powered Telecom Towers Need Better Batteries
Most off-grid telecom towers with hybrid renewable energy systems have used lead acid batteries. Like diesel fuel, lead acid batteries also incur ongoing maintenance costs for tower operators. Many lead acid batteries need to be watered and cleaned, which means a lot of travel hours for maintenance personnel.
Lead acid batteries have operational restrictions, too: they’re sensitive to heat, and they can’t run outside a narrow depth of discharge band or stand too long at partial state of charge. Violating these parameters can quickly kill the batteries, adding cost for new batteries and their installation.
Tower operators have started using some newer energy storage technologies, such as fuel cells and lithium-ion batteries. Greater storage capacity could also enable cell towers to distribute excess solar power to off-grid or weak-grid communities--so-called “tower power.”
If you think increased access to communication and information is a good thing, the growing number of remote telecom towers is reason to celebrate. If you think reducing the carbon footprint of all those phone calls, Tweets, and cat videos is also a good thing, the growing trend of renewable hybrid power systems in telecom towers will definitely make you smile.