Internet Protocol version 4 (IPv4) is dead — long live Internet Protocol version 6 (IPv6). That’s one way to frame the news from CNET that, in the coming weeks, the Internet Assigned Numbers Authority is going to hand out for distribution the last blocks of the roughly 4.3 billion addresses available under IPv4. That seemed like enough back in the late 70’s when Vint Cerf decided to use 32-bit addresses for the Internet. But beyond improved functionality and security features, IPv6 also uses 128-bit addresses, which should make the supply pretty much inexhaustible. So what does this mean for green technology? Well, the smart grid is just the tip of the iceberg when it comes to creating an “internet of things” that will commune with each other via IP — and companies that are relying on IP for their smart grid plans had better be up to speed on IPv6. Indeed, would-be smart grid giant Cisco and smart grid networking upstart Silver Spring Networks have been touting the virtues of IPv6 for years now.