The Hawker Beechcraft 4000 twin-engined jet was on its way from Cardiff in Wales to Charlotte in North Carolina where Garcia (33) is due to play in the Wells Fargo Championship in Quail Hollow on Thursday.
There were three people on board the jet, which was about 300km off the Irish coast when the crew contacted air traffic controllers at Shannon to declare an emergency. The pilot reported a "generator problem" and expressed concern that the jet might have to be towed clear of the runway after landing.
The Irish Coast Guard was informed, and search and rescue units were also placed on alert.
The jet touched down safely at 2.22pm at Shannon and was able to vacate the runway under its own power. It was directed to a remote parking area tailed by emergency vehicles.