Bharti Airtel's Africa division has announced that by 2013 it will have moved away from the use of diesel at tower telecom sites in its 16 operations on the continent and instead use an energy mix that will include solar and wind energy.

So far, Airtel has reduced the number of tower telecom sites running solely on diesel by more than 50 percent.

"This milestone is the result of significant steps by Airtel taken to ensure that we reduce our fuel consumption and that we play our part in conserving the environment," said Eben Albertyn, Bharti's chief technical officer.

Albertyn said Bharti's first priority is to reduce the number of sites that are completely reliant on diesel generators.

"We are doing this by connecting these sites to grid electricity in areas where this option is feasible," he said. "Where it is not, we are exploring alternative forms of power supply, which include Hybrid battery banks and solar/wind power."

Hybrid battery banks collect the excess energy produced by the diesel-powered generator in a battery that powers the site once the generator in switched off.

According to a company statement, the Indian telecom operator has moved 60 percent of its towers from diesel to hybrid battery banks. Bharti Airtel said that it has already made significant strides in using solar panels to power sites in select markets.

"Over the last two months, 105 solar sites have already been set up in Nigeria, reducing the use of diesel generators from 24 hours a day to a meager 3 to 4 hours," the statement reads in part.

In Africa, no other practice in the mobile telecom industry is more environmentally harmful than powering several hundred thousand of off-grid base stations by burning diesel fuel. One single diesel-powered base station can consume about 20,000 liters of diesel per year, and spew tons of carbon emission into the atmosphere.

Beside the environmental cost, high diesel prices get factored into what the users has to pay per phone call.

Over the last year, Airtel has reduced the number of telecom sites running solely on diesel by overcoming the challenges of lack of grid connectivity through what it calls innovative energy models such as hybrid battery banks.

By 2013, Airtel aims to completely eradicate the constant use of diesel to power its network.

"This means no telecom site of the company will rely solely on diesel power 24 hours a day," said Michael Okwiri, the vice president of corporate communications at Airtel Africa.

Joseph Kanyamunyu, the Airtel Uganda corporate affairs manager, said the company runs more than 700 tower sites. Ninety percent of the towers run on diesel, Kanyamunyu said.

Airtel Uganda spends over 1 billion Uganda shillings (US$400,000) on fuel per month. "The major challenge with the tower sites is vandalism, where people beat up the guards and steal the hybrid batteries," Kanyamunyu said.

Hybrid battery banks have helped reduce diesel use by up to 14 hours a day. Close to 60 percent of Bharti Airtel's telecom sites in Africa are now powered using the hybrid model, resulting in a major reduction in emissions and operating costs for the company.