Third-party verified evaluations remain relatively scarce for Controlled Environment Agriculture (CEA)-specific lighting fixtures and other products. And despite increasing market development, the energy-use profile of CEA facilities using commercially available products (such as LEDs) for energy-use savings is not well understood.
Pilot studies of different lighting products, configurations, and operating characteristics could provide valuable information about lifecycle costs for CEA lighting that’s not commonly available today. For example, check out the public-private partnership at GLASE that is working on LED technologies for greenhouse efficiency. Efforts like this are helping horticulturists justify investments in right-sized lighting equipment, advanced lighting controls, and fixtures that require less power to operate. Utility programs that incentivize lighting measures for the CEA sector could also benefit from knowing which equipment and technologies require incentivizing (Because of the profit potential, cannabis is on the leading edge. We wrote about that here). Reporting from in-progress scientific studies, work often funded by the USDA and researchers at Cornell University, Purdue University, Michigan State University (MSU), and the University of Arizona, suggests that LEDs when tested for operational considerations and performance are the key to CEA profitability.
Most purveyors of LED lighting claim that their technology will save anywhere from 40 to 70 percent of the energy used by HID lights for the same application. If this is true, it would represent huge economic and energy-savings possibilities. It would also present a significant new opportunity for energy-conservation practitioners to expand and diversify their commercial lighting program portfolios beyond the standard measures for energy-efficient office lighting.
Still, Real Savings are Contingent on Operations
If LEDs are carefully integrated into a lighting system design and control strategy, it may be possible to save even more than 70 percent, but that assumes a very high level of execution on the part of the manufacturer, integrator, installer, commissioner, and operator. Relative savings claims for individual end-use efficiency measures over standard HID lighting operation may include:
Energy saved by replacing a 1,000-W HPS with a 600-W LED fixture (40 percent)
Energy saved from lighting system control, monitoring, dimming, and daylighting (30 percent)
Energy saved with alternative lighting configurations and reduced light intensities (20 percent)
Energy saved from the adoption of energy-efficiency standards for CEA products (15 percent)
Energy saved by replacing a standard HID ballast with an LED driver (5 percent)
These estimates represent generic technical savings potentials for promising CEA lighting measures. Actual savings will vary considerably from one facility to the next, affected by building characteristics, new construction versus retrofit installations, incumbent lighting technology against which LED lighting is evaluated, the environmental conditions inside the grow room or greenhouse (primarily temperature and humidity levels), the type of commercial crop(s) grown, the grow-area and lighting configurations, the combination of measures for a given application, and other site-specific CEA facility and operations attributes.
Opportunities for Utilities
For now, it is unreasonable to assume that LEDs can save energy under all operating conditions and for any application; preliminary results from recent lighting experiments report higher energy use of red LEDs when compared to HPS lighting used to grow cucumber seedlings. The large diversity in operating conditions and requirements will most likely require the design and deployment of customized incentive programs, though it may be possible to develop prescriptive rebates for specific measures where highly consistent and reliable savings are observed over time or in exchange for solar power, including incentives for tested and qualified CEA lighting products.