"Turn off Google to save electricity" is a literal translation, but it might be better expressed as "Shut down Google services to conserve power" depending on the context. If you mean turning the screen black or reducing power usage by dimming screens that display Google services, it could also be interpreted as "Dimming Google interfaces to save energy." Could you clarify what you mean by “涂黑”? It could imply shutting down, darkening, or conserving in different contexts.