Last week General Motors announced that it plans to produce the world’s first plug-in hybrid SUV, in the form of a new yet-to-be-named Buick crossover. It seems that the sports utility-type vehicle will be resurrected and repurposed as a Buick.

G.M. says the baby Buick will be the “first commercially available plug-in hybrid produced by a major automaker.” Tom Stephens, G.M.’s vice chairman, announced the new model will first be released in 2010 as a gas-powered vehicle, five-passenger S.U.V. available with two sizes of direct injection engines—a 2.4-liter four-cylinder engine and a 3.0-liter V-6. The plug-in version planned for 2011 will curiously use a larger 3.6-liter engine.

The plug-in hybrid will have an 8 kilowatt-hour lithium-ion battery pack, using the same lithium manganese spinel cells as the Chevrolet Volt but in a size about half that of the powerpack in the Volt. The Buick’s hybrid system would operate on either gas, electricity or both.

The technology in the Buick is expected to result in more than 70 miles a gallon which is almost double than that of its gas-powered counterparts. The Buick hybrid’s gas engine will be a 3.6-liter V-6 that will be flex-fuel capable. The system also features two electric motors, and the battery pack can be recharged in four to five hours at 110 volts. It is also designed to be able to run for up to 10 miles in electric-only mode, but only at low speeds.

G.M. said the new vehicle would appeal to customers who like the Buick Enclave, but want a smaller more fuel-efficient version. The plug-in version will get double the fuel efficiency of the gas-only version but specific targets were not provided. Charging the plug-in Buick’s 8-kilowatt hour battery pack which is packaged under the cargo floor is expected to take four to five hours at 110V.