United Flight 1146 was on its way from Houston to Newark on Tuesday when it diverted to New Orleans. The 787 was carrying 174 passengers and 10 crew members. No one was hurt.
The plane remains grounded while the generator is replaced and the plane is checked further.
Boeing's 787 depends more on electrical power than other Boeing planes. That's because it uses electricity instead of air from the engines to power the main hydraulic system.
The 787 is equipped with six electrical generators: two provide power while the aircraft is on the ground; four of the generators provide all the electrical power needed during a typical flight, Lori Gunter, a Boeing spokeswoman, wrote in an email. If one of the four generators used during flight fails, the two used on the ground can provide power during flight.
Hamilton Sunstrand, which now operates as UTC Aerospace Systems, supplies the generators on the 787.
During the landing Tuesday, United pilots expressed concerns about the electrical bay in the back of the 787. In 2010, a fire broke out in that area of a 787 flight test aircraft. Boeing made design changes and software updates to address the issue before any 787s were delivered. No signs of fire were found on the 787 involved in Tuesday's emergency landing.
United Continental Holdings Inc. received its first 787 in September. The airline said its other two 787s are still flying.