The development of a fuel-powered miniature engine, touted as a more efficient and longer lasting alternative for the battery, may push the Energizer Bunny to the unemployment lines.

No bigger than a regular shirt button, the micro gas turbine engine uses the same process for producing electricity as its big brother electricity stations – burning fuel and running it through a power plant.

"Fuel and air in, and electricity out," said Luc Frechette, one of the Microengine Project team members at Massachusetts Institute of Technology.

Frechette is currently assistant professor of mechanical engineering at Columbia University.

At about one thousandth the size of a regular power station, the engine-on-a-chip will create about 1 millionth the power level, producing 20 watts of power at 2.4 million rpm from its cubic centimeter-sized package.

"It will give 10 times the amount of power that is generated by the best lithium battery," Frechette said.

And when the engine runs out of juice you just fill 'er up again. There's no need to wait to recharge or run out to the store for new batteries.

"If you take a laptop battery for instance, it's just a bit bigger than a deck of cards. The engine would take up the space of, say, a quarter. The rest of the space would be for the fuel tank," Frechette said.

"This fuel could last you for 24 hours and then, when empty, you can just refill the tank."

Weighing less than a gram, the engine is constructed from eight wafers of diffusion-bonded silicon and consists of a combustion chamber that ignites hydrogen and shoots hot gas past a spinning turbine that powers the compressor to drive the machinery.

The engine's tiny components -– the bearings, chambers and turbine – are precision etched onto the silicon.

"We use the same miniaturizing technology that is used in the microchip industry," Frechette said.

Building a complex 3-dimensional engine on such a microscopic scale is no mean feat.

"We're pushing micro-fabrication to a new standard," Frechette said.

One complication in developing components whose dimensions are measured in hundreds of microns is the difficulty in finding the right tools for the job.

High speed rotating machinery requires high precision manufacturing to maintain tight clearance and good balance.

To ensure that the millimeter-sized machines have the required fractional precision, the tools used to create them have to be made with the same exact precision -– one micron off and the resulting engine will be a non-starter.

There's also the issue of stress.

"The engine is a spinning man-made machine that goes at 2 million revolutions per minute. We don't know yet what kind of stress or problems this may have on the moving parts," Frechette said.

These aren't the only challenges in building the engine.

"When you scale things down you also create more friction, which results in more heat," Frechette said.

This means that using a micro gas engine to power, say, your cell phone may mean you will feel your ears burn -– literally.

"The engine generates a lot of heat. Burning fuel produces heat that needs to be evacuated – this means it won't replace the battery in all applications," Frechette said.

Once the problems of fabrication have been addressed, Frechette is confident that a complete system, with all the components in place, will be ready within the next year.

Frechette believes the first buyers will be from the military.

"The military are very interested in these. The small robots sent into the WTC rubble, for instance, had to be connected with cables to power them because their batteries are too heavy to carry," Frechette said.

The micro engine would eradicate these problems.

The commercial market will follow.

"For commercial use, the first application will probably be a battery charger – if not actually in a laptop it could sit beside it," Frechette said. "Instead of having to get to an AC outlet, you can carry your power supply along with you."

Representatives from battery manufacturers Duracell, Rayovac and Energizer were unavailable for comment.