The province is offering two free compact fluorescent lightbulbs to every Nova Scotian household to encourage residents to think green.

Premier Rodney MacDonald said the new program, announced Thursday, will help ensure a sustainable environment and economy.

The lightbulbs use up to 75 per cent less energy and last up to 10 times longer than incandescent bulbs.

If every home in the province switched one incandescent bulb to a compact fluorescent bulb, officials estimate, it would save enough electricity to power 2,000 homes for a year.

The program, which is costing the province $200,000, runs until May 20 at Home Depot stores.

Canadians have only a few years to buy incandescent bulbs: The federal government plans to ban their sale by 2012.

In Halifax, municipal officials are wondering what to do with discarded fluorescent bulbs, which contain a small drop of mercury.

Coun. Andrew Younger fears the heavy metal could start accumulating in landfills.

"If somebody can recover the mercury, you're effectively left with glass and metal," he said. "A lot of that could be recycled, so you could actually eliminate waste entirely."

But someone has to make that economically feasible, which could mean government incentives, Younger added.

The Valley Waste Resource Management system in the Annapolis Valley has started dealing with the problem by modifying a machine it uses for longer fluorescent bulbs.

"The machine itself creates a vacuum so that any dust is actually pulled down into the machine while the glass is broken," said Ken Redden, operations manager.

He said the mercury is sent to a hazardous waste site while the leftover glass and metal go to the landfill.