The "Moscone East" project would require the demolition of existing buildings at 50 Hawthorne St. and 680 Folsom St., which are owned by a joint venture of TMG Partners and Rreef. The project would connect underground to Moscone South, creating an additional 110,000 square feet of contiguous trade show and meeting space. The earliest likely opening date for the expanded convention center is listed as 2017.

The general idea is that the TMG and Rreef would pay the vast majority of the costs in exchange for the necessary approvals for the larger mixed-use development. The mix of uses beyond convention space would depend on market conditions. The meeting space would be built out using funds from the Tourism Improvement District, which collects a 1% to 1.5% tax on all hotels within the city.

Conventions and tourism is San Francisco's largest industry, according to the bureau, accounting for 17 million visitors who spent $8.5 billion in the city during 2008. The San Francisco Convention and Visitors Bureau believes firm plans for an expanded center would allow it to better compete for conventions with the likes of Las Vegas and New Orleans, which each boast a few million square feet for conventions.

Longer-term expansion plans also include widening the underground connection between Moscone North and Moscone South and growing Moscone Center West into 155 Fifth St., which is now occupied by Wells Fargo & Co. Joe D'Alessandro, president of the bureau believes all three expansions may be required eventually if the city plans to retain conventions such as the American Society of Hematology and Oracle OpenWorld, organizations that have said they may have to go elsewhere in order to find the space they require.

"The bottom line is the travel industry is San Francisco's largest employer," D'Alessandro tells GlobeSt.com. "If we aren't aggressive in expanding Moscone we will not be as competitive as we need to be in this extremely competitive marketplace."