Kenya Airways has selected General Electric’s GEnx-1B for its forthcoming Boeing 787 fleet as the contest with Rolls-Royce intensifies over the remaining customers yet to pick an engine.

The GEnx-1B will power the African carrier’s nine firm and four optioned 787 under an order valued at $380 million, using the list price for the 18 initial engines. The deal bolsters GE’s claim to about two-thirds of the 787 orderbook and underscores the company’s bullish outlook as it makes progress with the latest engine performance upgrade work. Commenting before the Kenya announcement, GE Commercial Engines VP and General Manager Bill Fitzgerald says the 787 engine market is busy again after more than a year in the doldrums. “The orderbook is active today, and we anticipate some big selections this year.”

The renewed activity follows entry-into-service of the first Rolls-Royce Trent 1000-powered All Nippon Airways 787 last October, and the imminent service entry of the first GE-powered 787 with Japan Airlines following its delivery on March 26.

The uptick in the tempo of engine marketing also comes as both GE and Rolls continue to perfect improvement packages to bring their engines up to Boeing’s original performance specification. Rolls expects to begin the certification process for the latest Trent 1000 upgrade in May, while the second of GE’s two-stage GEnx-1B performance improvement package (PIP) upgrades is close to completing initial flight tests on the company’s 747 flying testbed.

According to Boeing, more than 220 787s have yet to be allotted to a specific engine type out of a total of 868 unfilled orders. Of the six deliveries made to date, four are Rolls-powered and two GE-powered. Upcoming deliveries expected in April include another two to JAL and one more to All Nippon Airways. Beyond this, the 2012 deliveries are expected to have a mix of GE and Rolls powerplants, with further ANA and JAL deliveries as well as first GE-powered 787s for Air India, Qatar and United, on top of Rolls-powered 787s for LAN Airlines and LOT of Poland toward year-end.

Others yet to select an engine include Aeroflot (22) Air Berlin (15), Air France-KLM (25), Aviation Leasing (4), Aviation Capital Group (5), Biman Bangladesh (4), some 24 -8s and 35 -9s on order from International Lease Finance Corp., Jet Airways (10), Oman Air (6), Iraq (10), Saudi Arabian Airlines (8), Singapore Airlines (20), United (25) and VALC of Vietnam (8). Although Air China also is listed by Boeing as having selected the Rolls-Royce engine for 15 787-9s ordered in 2005, GE is believed to be trying to overturn this.

Continental also selected GE for its 25 787s pre-merger, so the unfilled United order also is expected to go GE’s way.