An Unstrung Insider report, Mobile Networks Go Green: The Lean Base Station, says that more than 90 percent of the next two billion subscribers live in emerging markets – the majority in rural areas without access to electric grids. According to John Blau, author of the report, the issue is twofold: to help develop alternative energy sources, and to create more efficient radio base stations.

“Operators want a technology that works, is inexpensive to deploy and has very low-cost maintenance,” Blau says. “They don’t want to send people out to fix these things or re-fuel them.” The basic premise is that inexpensive alternative energy must be used in combination with lean base stations to ensure affordable mobile access for subscribers in, primarily, developing markets. Blau considers the effects and benefits of five types of alternative energy sources: solar, wind, biofuels, fuels cells and pico-hydro energy.

Research shows that solar technology is the most mature of the energy alternatives being tested and deployed. In 2000, Maroc Telecom worked closely with Ericsson to become one of the first operators in the world to use the sun to power its base stations; today it has more than 100 sites. Blau says: "Clearly solar is the technology of choice moving ahead and is even showing appeal in developed markets, such as the US, where operators are looking at how they can extend networks in underserved areas.”

He says the main drawback to solar energy today is the theft issue. “A black market exists in some countries for solar panels that can be used for other applications,” says Blau. “So operators and vendors need to look at how they can build systems that can adequately protect the physical base station and its components."

As the technology to harness wind energy increasingly develops, so too does its commercial deployment. According to Blau, there is a growing interest in a hybrid solution using solar and wind energies. But the greatest interest currently is probably in biofuels, where Blau writes in his report that Ericsson and Indian operator Idea Cellular have tested the feasibility of using non-edible plant-based fuels to power up to 40 base stations. Blau suggests that today, fuel cells are too expensive to consider commercially and that pico-hydro is too much of a niche technology to be of widespread interest.

In the report he writes: “Although the capex invested in an alternative energy-powered radio site is higher than that required for a diesel-driven site or one already connected to the electric grid, the cost of power in the alternative energy solution, once installed, is almost zero...This translates into lower opex requirements – a crucial factor for emerging network operators.” He says that on average, an operator can expect to see a return on their alternative energy investment in three to five years, though some operators have managed it as quickly as in two.

In the meanwhile, Ericsson continues to actively research and develop alternative energy sources. Blau says as far as vendors go, Ericsson is in a strong position. “It has addressed the need for lean base stations as a requirement to be involved in this market. And it is present in so many countries with the know-how to build networks in literally all sorts of geographic conditions,” Blau says. “Ericsson is willing and active to work with all possible renewable energy systems – it’s looking at just about every option out there.”