L Prize

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The L Prize (aka the Bright Tomorrow Lighting Prize) was a competition run by the United States Department of Energy aimed to "spur lighting manufacturers to develop high-quality, high-efficiency solid-state lighting products to replace the common incandescent light bulb".[1]

The competition, launched in May 2008 at Lightfair, offered two prizes for the replacement of two types of bulb, an A19 60-watt incandescent light bulb and a PAR 38 halogen incandescent bulb. The prize fund for the 60 W replacement is up to a maximum of US$10 million and for the PAR 38 up to US$5 million.[2] There was a third category, yet to be publicly defined, called the 21st-century lamp.[3]

The competition set out various qualifying requirements for the replacement bulbs summarized in the table below:

60 W Incandescent Replacement bulb PAR 38 Halogen Replacement bulb 21st Century Lamp (Preliminary)[4]
More than 90 lm/W More than 123 lm/W More than 150 lm/W
Less than 10 watts Less than 11 watts
More than 900 lumens More than 1,350 lumens More than 1200 lumens
More than 25,000-hour life More than 25,000-hour life
More than 90 CRI More than 90 CRI More than 90 CRI
2700–3000 K CCT 2700–3000 K CCT 2800–3000 K CCT


It was announced on 3 August 2011, that the winner of the 60 W replacement bulb competition was a bulb made by Philips.[5][6] The winning bulb was a LED lamp using less than 10 watts and emitting the equivalent amount of light as a traditional 60-watt incandescent bulb. That amounts to an 83% energy savings. It was announced that Philips would be given the US$10 million cash prize.[5][6] The bulb was released commercially in February 2012 through several online sellers. The widespread launch at retail stores, however, was not until Earth Day, April 22.[7] Although the subsidized price was expected to be $22 in the first year, $15 in the second and $8 in the third, the bulb was initially selling for $50–60 (without rebates) as of July 2012. Many stores sold out, and according to Philips customer service the L-prize bulb has been discontinued.


The winning bulb is able to achieve all of the required specifications by using red and blue LEDs that excite yellow phosphors, which emits the required color of light. This is in contrast to most other LED lights, which use white LEDs to emit light that lacks some of the required characteristics for the L-Prize.

L Prize winning bulb on the right and its technological precursor on the left
Philips 60 W Incandescent Replacement bulb
DOE testing Consumer labeling
93.4 lm/W 94 lm/W
9.7 watts 10 watts
910 lumens 940 lumens
97.1% lumen maintenance at 25,000-hours (95% confidence)
93 CRI 92 CRI
2727 K CCT 2700 K


PAR 38 floodlight[edit]

The rules for the PAR 38 lightbulb competition were redefined in July, 2012, keeping the same main specifications. As of June 13, 2014, the competition has been suspended.[8]

21st Century Lamp[edit]

On August 1, 2011, Cree announced that they had created a bulb that would exceed the DOE specifications for a 21st-century lamp. It emitted 1,300 lumens at 152 lumens per watt with a CRI of 91.2 and a color temperature of 2800 K.[4] They also stated at the time that they would not be bringing the bulb to market. As of March, 2013 they had not brought the bulb or any bulb like it to market.

New L-Prize® competition, launched in May 2021[edit]

On 19-May-2021, the US DOE announced[9] a new L-Prize competition:

"The L-Prize is primed to unlock the full potential of LED technology—to combine high efficiency with exceptional lighting quality, data-driven control and functionality, and innovative design, construction, and grid flexibility."


  1. ^ "www.lightingprize.org". Archived from the original on 2018-08-11. Retrieved 2009-12-12.
  2. ^ "LPrize-Revision1.pdf" (PDF). Archived from the original (PDF) on 2016-12-25. Retrieved 2009-12-12.
  3. ^ "L-Prize Requirements". Archived from the original on May 6, 2011.
  4. ^ a b "Cree News: Cree Prototype Exceeds DOE's 21st Century Lamp L PrizeSM Requirements (01Aug2011)". www.cree.com. Archived from the original on 2013-12-27.
  5. ^ a b "DOE Announces Philips as First Winner of the L Prize Competition". U.S. Department of Energy. Archived from the original on 6 October 2011. Retrieved 6 August 2011.
  6. ^ a b "LPrize-winner_media-kit.pdf" (PDF). U.S. Department of Energy. Archived from the original (PDF) on 6 October 2011. Retrieved 6 August 2011.
  7. ^ "Award Winning LED Bulb". Philips Lighting Catalog. Philips. Archived from the original on 2012-12-17. Retrieved 8 February 2012.
  8. ^ "L-Prize - Bright Tomorrow Lighting Prizes -- PAR38 Replacement Competition". Archived from the original on 2015-02-17. Retrieved 2015-03-03.
  9. ^ "L-Prize Competition". L-Prize Competition - Department of Energy. Retrieved 12 July 2021.

External links[edit]