If Boeing exercises its buy option, it will acquire just under 1,100 acres. Boeing's current campus is owned by the aviation authority, which runs Charleston International Airport, and is leased by Boeing for $1 a year, he said. The aviation authority said it has been told Boeing will exercise its option to buy the land its current campus and plant sits on in 2025 when the incentives that the state gave to Boeing when it came to South Carolina run out. Boeing's $1-a-year lease on the property runs out in 2021, said Becky Beaman, aviation authority spokeswoman, but there is a four-year extension option built into the lease that Boeing will take. The value of the additional land, which is also owned by the aviation authority, is yet to be determined, Limehouse said. He said the land is probably worth about $18 million to $20 million. The price is "a good question," Limehouse said. "Some of it's very low and it's very expensive to fill. Most of it is wooded and a lot of it is low.