NEW YORK (CNNMoney.com) -- Americans are used to hearing that their energy supplies are dwindling.

But new discoveries of huge new natural gas fields in the United States and Canada could change that, cutting foreign imports and boosting production of a relatively clean energy source as global warming concerns take center stage.


Natural gas is used to generate about 20% of the nation's electricity and heat half its homes. Many people also use it for cooking, and its seeing a small but growing use in vehicles.

Prices and production were fairly low during the 1980s and 90s, but growing demand for energy globally, and an increased interest in cleaner fuels, has sent natural gas prices sharply higher.

Over the last few months, big gas discoveries have been announced in the Northeast, Louisiana, and British Columbia. Together, they could boost natural gas reserves in the United States and Canada by up to 10%.

These new fields are what experts call "unconventional" natural gas. What makes them unconventional is the geology.