When PHP 7 was released, Rasmus Lerdorf, the creator of PHP, said the performance improvements meant fewer servers, smaller memory use and reduced CPU activity

When PHP 7 was released, Rasmus Lerdorf, the creator of PHP, said the performance improvements meant fewer servers, smaller memory use and reduced CPU activity - all of which equalled less power or electricity consumed. (And remember this is an interpreted language.) When you consider the millions of servers in use, that additional language efficiency adds up to a substantial saving in electricity use. You can watch a segment from his presentation where he talks about this here - and the calculations he made of potential CO2 savings: https://youtu.be/umxGUWYmiSw?t=15m16s https://youtu.be/umxGUWYmiSw?t=15m16s