BG Group said a preliminary evaluation of its Jodari-1 exploration well found it contained a gross recoverable reserve estimate of 2.5 trillion-4.4 trillion cubic feet of natural gas.
The discovery is BG Group's fourth in Tanzania. The well is about 24 miles off the coast of Tanzania in about 3,700 feet of water.
The World Bank announced last year that it approved an International Development Association credit of $27.8 million to back Tanzania's energy expansion projects. The bank said the financial assistance would help cover costs tied to replacing or upgrading transmission lines and other equipment on the country's electrical grid.
U.S. Secretary of State Hillary Clinton, during a trip to Tanzania last year, said the "single biggest reason" for a lack of regional development "is because of the lack of energy and the inability to deliver electricity to people where they can use it."