LED Bulbs

https://en.wikipedia.org/wiki/LED_lamp
http://www.slate.com/articles/business/the_juice/2016/02/led_bulbs_are_about_to_be_everywhere.html
http://www.wired.com/2011/08/ff_lightbulbs/

Related
http://www.telegraph.co.uk/news/science/science-news/12093545/Return-of-incandescent-light-bulbs-as-MIT-makes-them-more-efficient-than-LEDs.html