Royal Philips Electronics has been clawing its way to the top of the LED market and last week the company again was able to distinguish itself from competitors when it announced it had developed an LED in a tube lighting (TL) form factor— a TLED—that can produce 200 lumens per watt, a level that Philips claims is a record and roughly twice the efficiency of standard fluorescent tubes.
These TLEDs are still in the prototyping stage and there currently isn’t any discussion of how much these TLEDs might retail for. So, for now, I will have to skip over the cost effectiveness/payback period issues and focus on relative energy-efficiency analysis.
In brief, current fluorescent tubes are still among the most energy-efficient forms of lighting, achieving 100lm/W, or more, and are fairly inexpensive (of course, the downside of fluorescent tubes is the mercury content and related disposal issues). Fluorescent replacements for traditional incandescent bulbs are a ways down the efficiency scale, achieving about 50-60lm/W. In between the two types of fluorescents are the current generation of LED bulbs, which achieve about 75lm/W. At the lowest end of the scale are the traditional incandescents that produce about 15lm/W. Philips says another way to think about the company’s innovation is that a 7.5W version of Philip’s TLED will produce the same amount of light as a 100W incandescent.
Philips, with some justification, argues that the TLEDs could cut lighting energy use in half. A news release says
In the US alone, for example, fluorescent lights consume around 200 terawatts-hours of electricity annually. If these lights were all replaced with 200lm/W TLEDs, the US would use around 100 terawatts-hours less energy (equivalent to 50 medium sized power plants) saving more than $12 billion and preventing around 60 million metric tons of CO2 from being released into the atmosphere.
The other side of that coin is that, depending on retail costs, energy costs and prevailing government policies, some consumers will nullify some of the potential energy savings by increasing their overall level of lighting.
Nevertheless, Philip’s work should be hailed as a breakthrough. According to a company technical document, the TLED achieves its “high-quality white light” by leveraging the high efficiency of indium-gallium-nitride blue LEDs and carefully combining their output with a red LED. Some of the InGaN blue LED output is converted into green via a phosphor absorption/re-emittance system. The mix of blue, green, and red delivers the desired color temperature and color rendering index. Other LEDs (e.g., yellow LEDs) actually are able to achieve even better energy efficiencies, over 300lm/W, but so far no one has found a way to make them useful in achieving the targeted light mix.
Philips also achieved notoriety in late 2012 when the company introduced its Hue-brand LED lights that can be controlled with Wi-Fi enabled smartphones and tablets.