Exelon Generation Co. hopes to decide by New Year's Day who is going to buy the square-columned Peco Delaware Station power plant that the company owns on 16 acres between the river and Interstate 95, just north of Center City.

More than a dozen would-be owners walked the property this fall, and Exelon managers and their real estate brokers at Binswanger are still weighing best offers, Exelon spokesman Bob Judge told me.

Nearby, the vacant field once proposed for a Trump Tower complex, approved for the Northern Liberties waterfront at 709-717 N. Penn St., but never built, is for sale by U.S. Bank and other lenders who foreclosed on the two-acre site.

What to build on these ex-industrial sites? If he were mayor of Philadelphia, "I would develop an unbelievable business community on the water" to attract creative young engineers, says Bill McDermott, Newtown Square CEO of global business software giant SAP SE. The city's waterfront is really under-leveraged, he told me.

Most likely, the ex-Trump site will be apartments, says Michael Barmash, senior vice president at broker Colliers International, which is collecting offers on the site through March 2.

Before the recession, Barmash sold the nearby property where the three Waterfront Square high-rises now stand for $10 million. Now "Philadelphia's on fire" again for apartment projects, Barmash claims.

It's a different story farther south. Sunoco Logistics' conversion of the former Sun Oil Co. refinery into the gas-based Marcus Hook Industrial Complex is expected to attract more industry, not riverside living, to ex-factory sites nearby.

The recently closed Evraz Steel mill in Claymont between I-95 and the river, along SEPTA and freight rail lines, and just below the Delaware state border, got hopeful news in November. A St. Louis industrial-land recycler, Commercial Development Co., said it hoped to buy the 425-acre site, demolish the mill, clean the ground, and find new users.

Commercial, which is also fixing up the ex-Bethlehem Steel site at Sparrows Point, Md., hasn't closed the Claymont deal, which "may extend into early January," chief executive Randall Jostes told me last week.

No one's talking about high-rises here.

"We're concerned about employment and careers and jobs," said New Castle County Councilman John Cartier, who represents the district. He calls Sunoco Logistics' new gas terminal fortuitous, and expects that its cheap fuel will draw manufacturers back to Claymont.

But Cartier, an avid recreational boater, also says the tree-grown fringe of the property along the river would make a nice marina. Northeast portions of Delaware have few docks and little river boating, a condition blamed partly on its restrictive Coastal Zone Act.

"When we had an active steel mill, none of this was feasible," Cartier told me. "But now the whole northeast of this county is really in play. We need to do a master plan."

215-854-5194 @PhillyJoeD