Santos to sell gas to Alcoa

Energy giant Santos has sealed a deal with alumina giant Alcoa to supply it with natural gas from the Carnarvon Basin, off WA.

Santos has struck a deal to supply natural gas to Australia's biggest alumina producer Alcoa. (AAP)

Santos has struck a deal to supply natural gas to Alcoa of Australia, the country's biggest alumina producer.

Under the five-year deal, which begins in 2018, Santos will supply 82PJ of gas from the Carnarvon Basin off Western Australia to Alcoa.

"This is a significant contract for us, not only in terms of its value but also in its tie-up with WA's biggest buyer of natural gas," Santos general manager WA & NT Brett Woods said on Monday, adding that the deal allows for two five-year extensions.

Santos shares were 16 cents lower at $7.68 at 1023 AEDT.