I just stumbled onto this article from 2011 about a bulb cree was making
... That's ~153 l/w. That was three years ago. I want them to finish and release this bulb!
In 2010 Cree anounced they broke the 200 l/w barrier. Last May they announced the commercial availability of that performance:
"XLamp® XP-L LED, the first commercially available single-die LED to achieve breakthrough efficacy of up to 200 lumens per watt (LPW) at 350 mA"
-- http://www.cree.com/News-and-Events/Cree-News/Press-Releases/2014/May/XPL-intro
XP-L is the diode
the new Area-51 models will have. (<<link). Expected
in April. (<<link)
I like the simplicity of the E27-base (screw-in) lightbulbs. No cooling fans, distributed lighting with more sources of light from different angles. They're ~100 LPW for the Cree A19 lightbulb (Home Depot) and ~110 for the SMD 5730 "corncob" bulbs sold on AliExpress (presuming they're not counterfeit).
You can get a fanless 140 LPW from COBs if run at lower current and on larger heatsinks. That requires a considerable investment in aluminum heatsinks and cobs (need more for total lumens when running them at lower current). I'm sure it pays for itself, but I think even at lower power they're still not the best choice for smaller grow spaces. Seems they still can't be placed right up against the plant for diffuse light like the Cree A19 (Home Depot) bulbs.
T5HO is about 92 LPW. The Cree (Home Depot) bulbs are ~92 LPW with their frosted diffusion globe (would be ~100 LPW with that broken off, which some people do -- but you need to put plug it into a GFI to make those exposed surfaces safe). The SMD 5730 is about ~105-110 LPW in its clear plastic globe (not as diffuse).
So, it's an interesting time right now as LED tech is turning a corner. Commercial brands have COB lights they'll release soon (140-160 LPW). A51's XP-L. Over time, as the manufacturing processes mature, these efficiencies will make it into the screw-in lightbulbs.
I don't see any reason to use CFL right now unless it's a cold climate and a person needs the heat from CFLs. T5HO is on the fence with me. It's fairly efficient but doesn't have great penetration. You can get these 90-100 LPW LEDs in a PAR38 spotlight (18w actual) for greater penetration.
I used to grow T5HO. I still have the fixtures and thought about using them this winter. But, the options for concentrating them or breaking them up into more discrete, aimable, positionable sources of light seems like a downside compared to the equally efficient "lightbulbs" that are now available. Maybe T5HO offers something I'm overlooking.
Either way: grow light technology is turning a corner right now. In a couple years I think T5HO will be comparatively the same as CFL is today. I don't think the high-powered COBs and XP-L chips are going to do it because T5HO is good for that up-close diffuse light. But, in a couple years those efficiencies will find their way into softer lightbulbs.