Changing Skyline: Is it lipstick on an energy hog?

The ocean liner-size building that just docked on North Broad Street, complete with a big glass prow to soak up the afternoon sun, does not look like the sort that helps the environment. Sprawling across 20 acres, the Convention Center is essentially a big box of meeting rooms that need to be heated and cooled. Its roof is a lifeless Sahara, devoid of vegetation or solar panels. And yet the project is on track to earn a silver award from the U.S. Green Building Council.

Somehow this does not compute.

The silver rating, third place on a scale of four, tells us at least as much about the weaknesses of the popular accreditation system - known as LEED - as it does about Philadelphia's $800 million hospitality powerhouse. Can a building that encourages thousands of airplane flights and road trips possibly be considered the least bit green?

In the macro sense, no. But on a micro level, the answer is, yes, sort of.

The creators of the LEED rating acknowledge its imperfections, but defend the system as an effective prod that has pushed building owners to reduce their carbon footprints. Energy hogs who never gave thought to the impact of solar glare (i.e., that strong afternoon sun), or the off-gassing from synthetic carpet, are now forced to confront those issues to win the building council's coveted seal of approval. LEED encourages baby steps, not revolution.

The Convention Center may rank as one of the group's great salvage efforts. Back when the Broad Street addition was being designed in 2001 - by Philadelphia's Vitetta architects and Atlanta's TVS Design - almost no thought was given to curbing electrical and water consumption, never mind limiting the use of noxious chemicals in paint and furniture. By the time the project was ready to break ground in 2008, the meeting hall still hadn't made much progress, even though competitors like Pittsburgh's David L. Lawrence Center had already slashed their energy bills 35 percent by going green. It won LEED's gold rating - in 2004.

Maybe it was the prospect of being Philadelphia's most prominent un-green building, but the Convention Center Authority did ultimately tweak its design, albeit late in the game.