Sunbathers by Lindz McLeod PB

Sin is hot but purity is blistering.

Hordes of cannibalistic sun-vampires rule the daylight hours, forcing the remaining humans to adapt to a grubby, nocturnal existence. When she sacrifices everything to become a Sunbather, queer Soph discovers that the heterosexual commune is not the glowing paradise she'd hoped for, and her new immortal body still yearns for womanflesh. After discovering that the Sunbathers are building a solar lamp that will enable them to walk in permanent light, Soph must decide if she's willing to doom what's left of humanity just to finally fit in.