Bergey Windpower notes the growing use of wind power in cell phone stations.

Safaricom (www.safaricom.com), headquartered in Nairobi, Kenya, is the largest cell phone provider and the most profitable company in East Africa. As they have moved to extend their service range to the rural areas of Kenya they have encountered more and more sites for their base stations where no utility power is available. The normal practice at such sites is to use two diesel generators, one operating all the time and another serving as back-up. But, diesel power is far from ideal. Supplying fuel in areas where the roads are very poor and armed escorts are sometimes required is very expensive. Also, the diesel generators are under-loaded so they are not operating very efficiently and they require more frequent maintenance.

In 2005 Safaricom contracted with Winafrique Technologies in Nairobi to design and supply pilot wind/diesel hybrid systems at three very remote base stations. The systems consisted of a Bergey 7.5 kW turbine on a 24 m (80 ft) SSV tower, sealed batteries, and an inverter. These sites were installed and monitored for one year. The results showed excellent reliability and diesel fuel savings of 70-95%. Based on these positive results, Safaricom has contracted for six more sites, and has many other wind/diesel sites in the planning stage.

They go on to describe its use in a remote town, Laisamis:

Even though Laisamis is very remote and the household income is very low, the new Safaricom base station is already handling thousands of calls a day. In fact, the lack of electricity to charge local cell phones has emerged as a barrier and Safaricom will soon add a battery charging station to their base station facility. That too will be powered by the wind. Cell phones allow children to talk to parents who have gone to work in the major cities, law enforcement to spread the word on cattle thefts, and clinicians to seek the advice of doctors.

UPDATE, September 2007: Safaricom will have over 25 sites with Bergey 7.5 kW turbines installed by the end of 2007.

AfriGadget comments that "Hybrid systems that utilize renewable energy such as wind and solar are making it possible to extend wireless service in remote areas that are not connected to grid power." More recently, the systems have been adopted in Namibia.