The peak efficacy achieved by commercially available LPS lamps is 183lm/W for the lamp itself.  However LPS control gear is hugely inefficient, wasting around 15% of input power, so the real system efficacy is far less than the lamp figures alone would imply.  Due to the large source size the optical efficiency is also poor - as little as half the luminous flux is directed on the intended area for typical luminaires.  The whole system is therefore comparable to HPS lamps with ca. 100-120lm/W.

The peak efficacy achieved by commercially available white LEDs, with CRI>80, when hot and driven at reasonable currents vs 25C datasheet conditions, is around 200lm/W.  Moreover LED drivers are much more efficient, in higher powers regularly exceeding 95% efficiency.  Optical control is outstanding and the light output ratio from good fixtures can approach 90%.  Therefore the complete system far outstrips the performance of LPS.

LPS would still be a good contender if more electronic ballasts had been developed for these and if you just needed an uncontrolled flood of light in all directions, but since the vast majority of fixtures require the light to directed in a particular distribution, it’s actually one of the least efficient systems.  Hence why the development of LPS fixtures and systems was stopped around the end of the 1980s.

Is it true that the optical design of LED fixtures and lamps makes LED lighting the world’s most energy efficient light source? I did have doubts about it’s energy efficiency when I saw some LED retrofit lamps and fixtures having a lower luminous efficacy compared to some discharge light sources such as some HPS, some fluorescent, some MH, and even LPS. Is the claim about LED lighting being the world’s most energy efficient light source a common reason for a country to ban all non-LED lighting?

Nope