The One Laptop Per Child Project (OLPC) is toying with a novel source of power for its low-cost XO laptops: cows.

"We plan to drive a dynamo (taken from an old Fiat) through a system of belts and pulleys using cows/cattle," wrote OLPC's Arjun Sarwal, in an e-mail dated October 21 and posted to one of the group's discussion lists.

Sarwal and others are now finalizing the design of the cow-powered generator.

The goal is to develop a low-cost energy source that can be used in Indian villages. Working in a village close to Mumbai, Sarwal said the group considered using solar energy but sunlight near Mumbai was not "consistently strong." There was not enough wind or running water nearby to use these as sources of power, and the cost of running a gas-powered motor was too high.

"But the village had an abundance of cattle that were being used in the fields. So we decided to design something around that," Sarwal wrote in a subsequent e-mail.

The dynamo used in the system was taken from a Fiat car that is commonly used as taxis in Mumbai and therefore both cheap and readily available.

OLPC is close to putting its XO laptop into production, but has been beset by delays and rising costs. Originally intended to cost US$100 each, the cost has since risen to nearly US$200. And production is also moving slowly.

After a trial production run in August, OLPC had hoped to start mass production in late September or early October. That date has now slipped to November 12, according to a Reuters reportthat quoted the group's chief technology officer, Mary Lou Jepsen.