The capability to provide artificial sunlight has dramatically
expanded the boundaries of time and space, adding hours to the day when
we may see and illuminating where sunlight was unable to penetrate.
Since the first humans carried a torch to provide light, heat has been a
by-product of producing light.
Traditional electric lights continue to give off more heat than
light. An incandescent light bulb uses a paltry 10 percent of its energy
to create light. Fluorescent lighting -- which has been the green
standard in energy efficiency -- still wastes nearly half of the
electricity it consumes in generating heat. All of this lost energy is
significant considering that lighting devours more than a quarter of a
typical commercial building's electricity, as reported by the U.S.
Energy Information Administration.
LED, or light emitting diode, fixtures, in comparison, are twice as
efficient as fluorescents at converting electricity to light and hence
generate very little heat. In addition to improved energy efficiency,
LED fixtures are nearly maintenance free and provide high quality of
light. They are also dimmable, contain no mercury and tolerate frequent
on/off switching without degrading their lifespan.
LED Case Studies
Since UCSF Medical Center replaced
some of its surgical lighting with LED fixtures, doctors and nurses no
longer complain about the heat from the light fixtures when performing
surgical procedures.
"Previously we had to chill the OR [operating room] to offset the
heat generated by the old fixtures," UCSF Project Manager John Lewis
explained. "The new LED lights do not radiate heat and the OR medical
staff is comfortable at standard OR temperatures."
Quality of light is an important issue to adoption of any new
lighting technology. Fluorescents were unable to replicate the
incandescent bulb's soft and pleasing glow and disappointed both
professional lighting designers and the cube dwellers who toiled under
their unnatural glare. LEDs hark back to a more basic light source, the
sun. The spectrum and color rendition come closest yet to natural
daylight.
An LED is a semiconductor that creates light by releasing energy from
electrons. It is frequently referred to as "solid state" or "digital"
lighting. Because LED fixtures generate light over an area using
thousands of tiny light sources, the fixtures also provide a clear,
shadow-free light field that is ideal for task work, whether an
accountant, engineer or surgeon.
"The most important criteria for our application is the quality of
light. After an early test, we eliminated fluorescent fixtures since
fluorescents render colors poorly," Lewis said. "The medical team found
the quality of light provided by the new LED lighting was superior to
the existing incandescent lighting."
While quality of light is important, CFOs, facilities managers and
contractors also want to understand the financial benefits of LED
fixtures. LED lighting providers emphasize the lower total cost of
ownership offered by LED lighting to justify the higher upfront
investment.
Much of the savings stems from the improved energy efficiency of LED
lighting; up to 70 percent less energy is required to produce light. An
added benefit is reducing heat generated, which saves on air
conditioning and is noticeable in an operating room, office or data
center.
Adding to the cost benefits, LED manufacturers promise an
exceptionally long life of 10, 15 or more years. Shifting from
disposable to durable lighting eliminates the maintenance costs such as
tube and ballast replacement that are standard with fluorescents. Adding
to replacement costs is proper disposal of the mercury-based
fluorescent tubes.
The Pittsburgh International Airport found the ROI compelling. The
airport is installing more than a thousand LED fixtures to cover over a
million square feet in its garage (pictured below) and passenger loading
and unloading area. The project is believed to be largest single
installation of LEDs to date.
"Not only does the LED
technology reduce our energy costs, it also reduces maintenance," said
JoAnn Jenny, director of communications for Allegheny County Airport
Authority.
To further improve ROI, there may be grants and incentives available.
Pittsburgh International Airport is taking advantage of a state grant
to subsidize installation of LED lighting. With the grant, the pay-back
period is cut by half.
Barriers to Adoption
Although LED fixtures offer compelling advantages, there are barriers
to adoption. Kim Parsley, a principal for IA Interior Architects, which
focuses on sustainable commercial building design, commented, "We are
still recommending T5 fluorescents for office and retail spaces. We are
cautious about the claims of LED lighting providers and want more case
studies. The upfront costs are also off-putting to clients."
To overcome these early adopter risks, Pittsburgh International
Airport first completed a small pilot and then negotiated guarantees
from its vendor that the LED fixtures would achieve the advertised light
output, efficiency and life expectancy.
LEDs are starting to light standard commercial installations such as
offices and retail. Last year, Unilever's new 400,000-square-foot
headquarters (pictured above) used LEDs as primary electric light
source. Starbucks also announced last year its plan to retrofit all of
its 8,000 company owned stores with LED fixtures and is on-track to
roll-out by the end of this year.
Costs are expected to decline with continued improvement in
performance. Sandia National Laboratories completed a LED study in 2001 [PDF] to develop a price
/ performance model. In that paper, Drennen, Haitz and Tsao described
LED improvements over the previous thirty years, "In a Moore's-law-like
fashion, [light] per unit has been increasing 30x per decade ...
Similarly, the cost per unit … has been decreasing 10x per decade."
Improvements in this decade have been consistent with the model.
Implementation Considerations
The most favorable ROIs are for those applications where the lighting
is expensive to operate:
- Energy intensive -- Where there is long hours of operation,
inefficient technology such as incandescent, halides, or halogens. These
applications include garages, hospitals, retail, airports and other
transportation hubs, decorative lighting, signage, elevator and
restaurants.
- Costly maintenance -- Frequent replacement required. Expensive
to replace parts when using traditional fixtures. Examples are signage
or outdoor lights.
Even when the ROI satisfies the company's hurdle rates, other
complications may limit the realization of benefits. Since many
commercial buildings are leased, if the installation pay-back period is
longer than the lease or the tenant does not pay for electricity used,
then the tenant has no incentive to make the investment. In these types
of scenarios, the tenant and landlord need to negotiate to determine an
equitable way to share the costs and benefits of an LED installation.
When selecting LED providers, the Department of Energy (DOE) has
established a certification program to test and compare various LED
products. Since technology advances continue, DOE and other industry
groups should be checked periodically for latest insights.
No matter the lighting technology selected, the first step is to
reduce the lighting required and then find the most efficient technology
for the remainder. Incorporating day lighting reduces the need for
artificial lights. Presence detectors and automatic dimming to maintain
correct level of light will eliminate waste.
LEDs Ready for Expansion
The newest use for LEDs, developed by NASA, is to provide light to
grow plants for oxygen and food in space. The research from this space
application has been transferred to medical uses in the treatment of
cancers (see picture, right).
The nonprofit Light Up the World Foundation is developing and
distributing solar LED lighting to poor people in remote areas who still
rely on kerosene lamps and wood fires. This old style lighting creates
toxic emissions that debilitate the health of those exposed; especially
vulnerable are the young and chronically ill. The new LED light is
appreciated for its bright illumination as well as its clean and frugal
operation.
The quest to provide artificial light has always been about
discovering more efficient and safer lighting technology. LED lighting
is the next step in that evolution. LEDs have already expanded from
niche lighting to standard commercial applications in the last few
years. And LED technology is helping to open new frontiers because of
its low energy requirements and ability to mimic sunlight.
Project and Other References
UCSF Mount Zion OR Project -- Design: Mazzetti, Nash, Lipsey,
Burch. LED Solution: Maquet Gmbh & Co
Pittsburgh Airport -- LED Solution: Appalachian
Lighting Systems
Starbucks Retail -- LED Solution: GE Consumer and
Industrial Lighting Systems
Unilever Headquarters -- Design: Licht 01
Lighting Design. LED Solution: Nimbus Group.
Light Up The World Foundation -- Strategic Partners: Phillips, Nemalux LED Lighting.
Resources
ROI Calculators: There are many on-line calculators available
from suppliers. Ensure that the calculator considers maintenance and
number of hours of operation. Although helpful that a calculator
provides default values for energy costs, existing lighting and other
parameters, it is best if these can be updated to reflect more
accurately the ROI for a particular installation.
DOE LED Testing Program (Caliper): www1.eere.energy.gov/buildings/ssl/caliper.html
Unique Characteristics of LED DOE: As identified by the
Department of Energy, LEDs have several unique characteristics that make
them ideal for specialized applications. For example, LEDs perform
better in cold temperatures making supermarket refrigerator cases a good
use. They also do not emit UV light. UV light will damage archival
materials and can be irritating to skin and eyes. For more LED
applications, the DOE created an excellent publication. (Download the PDF here.)
Claudia Girrbach is a senior director in the IT department at Gap
Inc., as well as a member of the company's EcoCouncil and Employee
Engagement Team. She also authors the blog Going Green - Tips for
Business. William Dinkel, an avid blogger on green
technologies and energy efficient solutions, contributed to the
reporting and research for this article. William works at
Hewlett-Packard and holds a BS in computer engineering from California
Polytechnic University, San Luis Obispo.