Soraa is spearheading an effort, involving a number of major players in the solid-state lighting (SSL) industry, asking the US Environmental Protection Agency (EPA) to lower the efficacy requirements in the evolving Energy Star Lamps version 1.0 specification -- only impacting products with a CRI of 90 or better. The group believes that more users will adopt LED-based retrofit lamps if Energy Star-recognized options are available with a higher CRI, and therefore the net energy savings throughout the potential US customer base will increase even though the lamps in question use marginally more energy.
According to Soraa, the loosely organized coalition of petitioners include the California Lighting Technology Center at the University of California at Davis; Shuji Nakamura the inventor of blue and phosphor-converted white LEDs; Steven DenBaars co-director of the SSL Center at the University of California Santa Barbara; well-known and outspoken lighting designer Chip Israel of Lighting Design Alliance; the International Association of Lighting Designers (IALD); and Northeast Utilities Companies (NSTAR).
The crux of the problem comes down to the fact that reaching high CRI values such as 90 invariably decreases efficacy. "Fundamental physics research shows that there is a ~2% penalty in luminous efficacy per point of CRI. So, going from a CRI of 80, where most LEDs operate, to a CRI of 90, there is a ~20% penalty in lm/W," said Shuji Nakamura, professor of materials and co-director for the SSL at the University of California, Santa Barbara.
The EPA lamps draft makes no allowance for CRI and color requirements in its Energy Star efficacy requirements for omnidirectional, directional, or decorative lamps. The draft requires a minimum CRI of 80 and specifies efficacy for different lamp power levels. The petitioning companies are asking for 5-10-point drops in efficacy requirements for lamps with a CRI of 90 as depicted in the nearby tables.
The EPA itself has pointed out in the lamps draft that poor color quality is a barrier to broader adoption. Focused on increasing SSL adoption, Chip Israel said, "Designers should have the flexibility to select the appropriate source for their applications and end users should have their right to purchase high color rendering or full spectrum lamps for their spaces."
The fear among the coalition is that designers and customers will simply stay with less efficient light sources, rather than transition to SSL products if the Energy Star label isn’t available with high-CRI products. The group is arguing that a transition using slightly less-efficient lamps will do far more to decrease energy usage across the US.
"The slow market adoption of CFLs over the last 20 years demonstrates that simply because a product produces enough light, saves energy and is cost-effective, broad market adoption of that technology is not ensured," said Carlos Alonso-Niemeyer, energy efficiency program manager of NSTAR. "To persuade consumers to purchase LEDs instead of incandescent lamps, LED lamps must be seen as high-quality products worth the initial higher price differential. Therefore, LED lamps must closely replicate the color rendering and color appearance of the incandescent and halogen lamps that they replace."
Soraa is a manufacturer of gallium-nitride-on-gallium-nitride (GaN-on-GaN) LEDs, and MR16 retrofit lamps that use the LEDs.