Last week, I attended Structure 09, the GigaOM Network’s second annual cloud computing and infrastructure conference, here in San Francisco, and I was struck by the increasing relevance of the space to the discussion around green and IT. As Katie has pointed out in the past, cloud computing’s “avoided costs” selling points map neatly to some green marketing messages that companies are beginning to leverage. But perhaps more notable to me was the expanding array of applications for which cloud computing is being used. In particularly, some of the coffee-break and cocktail-hour conversations floating around pointed to the increasingly “green” markets for cloud computing — the smart grid, in particular.