10 Questions for . . . Nadarajah Narendran, Ph.D., Lighting Researcher

In this installment of 10 Questions for . . . , Associate Editor Kimberly Janeway interviews Nadarajah Narendran, Ph.D., director of research at the Lighting Research Center at Rensselaer Polytechnic Institute, in Troy, New York. Narendran discusses the future of lighting and explains how LED lighting holds promise for hundreds of millions of people in developing countries worldwide.

Why is LED technology the next big thing?
They last longer, so there’s less landfill. And the light they produce is improving. It’s not great yet. We’re confident because there’s a lot more research money being put into LED technology than into compact fluorescent lightbulbs. Therefore LED technology will improve greater and faster. There’s no one perfect lightbulb in this world. It’s a matter of more pros than cons. Compact fluorescent lightbulbs are better than incandescent bulbs. But now LED lights have come in. The CFL market will be eaten up by LEDs. Not everything, but little by little.
(Our tests have shown that CFLs can lag in color rendering and run-up time.)

What else needs to be done to improve LED lighting?
For LED lights to be transforming, we need to look at the infrastructure. It’s a waste of “talent” if we put an LED light in an incandescent socket. One of the LED features is you can dim up and down and change color, from more yellow to blue. That doesn’t happen with incandescent bulbs. The existing sockets and fixtures do not have good thermal management. So now if we replace incandescents with LED lights, the LED lights may not perform optimally.

When will LED lights be more widely available and come down in price?
Over the next five years we’ll see more products in stores. Now they’re not commonly available, so it’s hard to see that LED lights are a good option.

Where will CFLs fit in as LEDs become more common?
LED lights and CFLs will coexist. With LED lights, the price is going to come down. Now they’re in the $20-to-$50 region for a consumer. Part of the reason is the products are coming from overseas.

Have CFLs been perfected?
CFLs are really good now, and the quality has improved. It did ramp up when leading manufacturers made them. It’s a better product, better lasting, with better light and less mercury, but more products are in the market and not all are performing the same.
(Look for our new ratings-based report of CFLs in the October 2009 issue of Consumer Reports, online and on newsstands in early September.)

Incandescent bulbs had a long run as the dominant lighting source. What precipitated the move toward more-efficient technologies?
The energy crisis of the 1970s and climate changes forced the need for change.
(Read our interview with Ed Hammer, inventor of the CFL.)

Other than CFLs and LED lights, are there any other lighting alternatives?
There are people trying to do other lighting. Some researchers are trying to even make incandescents more efficient.
(Learn about the White House’s plan to boost the efficiency of some fluorescent and incandescent lightbulbs.)

You’re working to improve the quality of life for South Asians through lighting. How can lighting accomplish that?
We take lighting for granted. But there are many millions of people who do not have access to it—they use kerosene and candles and can’t do activities after darkness. They rely on daylight and the day is short for them. If you can provide lighting at affordable costs, you can provide opportunities, knowledge, education, and economic growth.

How can lighting change a family’s life?
In the U.S., lighting is a smaller portion of our home energy use compared with air conditioners, washers, and TVs, and. In South Asia, the cost of running lights is a significant part of budget. So if we can help with lights that use one third or one-tenth of the energy then it will save money.

What kind of lighting do you expect will be used in developing nations?
LED lights are wonderful lights sources when you don’t have access to the power grid. These lights are the answer because power requirements are low. You’ll be buying fewer bulbs over time, so they’re more cost effective when there’s no power grid. And LEDs are much more efficient than CFLs and don’t have mercury and disposal issues.

Essential information: Our experts debunk some of the myths that surround CFLs.

Comments

[Dan Tong]

LED flashlight technology is good enough that by means of hand cranking or squeezing a handle you can generate sufficient electricity to keep an LED flashlight lit for quite a while. This makes them extremely useful for power outage emergencies, in the car or for camping, because instead of relying on batteries the power is self generated. Flashlights that require shaking appear to be far inferior to the two methods mentioned above. It also makes sense that these flashlights would be extremely useful in third world countries where electricity and batteries are very expensive, and hard to come by.

However, a common problem is that the quality of the workmanship, like the on/off switch for example, is quite poor. If you buy a flashlight from a catalog, or the internet, you cannot evaluate the quality of the workmanship. It would be very USEFUL for CU to test these self generated LED flashlights and or combination emergency radio/flashlights.

[Mac]

While researching outdoor lighting during a major remodel, we found at Home Depot [California] a line of LED outdoor fixtures priced very competitively. 2 years later all 12 fixtures work beautifully, the bluish light took a little time to get use to and also they don't seem to attract bugs like florescent or incandescent bulbs. When looking at LED lighting it is still difficult to translate how bright an LED fixture is compared to say a 100 watt bulb.

[Norbert Drewell]

The actual energy savings of "energy saving" devices such as the LED and CFL is over-stated in many cases. When used in homes that require heating in the winter, the "wasted" energy is not wasted, but instead contributes to heating the home and thereby offsetting an equal amount of energy that would otherwise be demanded of the heating system. If the heating system is required for 2/3 of the year, then the effective energy savings with these devices is only 1/3 of the hyped amount. Of course, the energy mix required by the home will be changed, and this may well impact the net cost to the consumer.

One the other hand, in places where air conditioning is used extensively, the actual savings will be higher than the advertised amount.

[Jimmy R Ratcliff]

I have purchased several lights of America led light bulbs of various sizes and all have either failed or dimmed greatly in two months of service.