The LED has conquered the world of lighting
“Any sufficiently advanced technology is indistinguishable from magic."
-- Arthur C. Clarke’s “third law”
That a semiconductor the size of a pinhead has revolutionized lighting does seem like magic: When compared to a traditional incandescent bulb, it can produce brighter light while consuming one-tenth of the power, can last 50 times longer and LEDs of different colors can combine to produce an almost infinite number of colors. As they’re solid-state devices, LEDs also fit neatly within the domain of IoT in which all things are connected and remotely controlled with an app.
So, it should surprise no one that LEDs outperform existing technologies in almost every market.
What’s perhaps equally remarkable is the speed at which the transition from legacy light sources to LEDs has taken place, especially in the consumer market. For more than a century, generations recall the yellowish glow of incandescent bulbs. For consumers, the only decision has been the size of the bulb’s screw-in base, its shape and its power consumption. Because all incandescent bulbs produce yellowish light in the same part of the visible spectrum there were no color choices.
LED metrics are different. Power consumption (e.g., 60 W) is no longer relevant because all LED bulbs consume very little power and one that produces the same output as a 60 W incandescent bulb consumes only 6 W. So, the brightness of LED bulbs is stated in lumens rather than watts. For the first time, the yellowish glow is no longer the only choice. LED bulbs are available in color temperatures from 2200K (warm white) that have a yellow or amber tint through (neutral 5,500 K, cool white that look blueish.
It didn’t take the lighting industry long to realize that the LED transition required handholding, and today lighting aisles are replete with demonstrations of what different color temperatures look like. For those who can’t decide, the spectrum of new human-centric lighting bulbs can be switched from 2,700 upwards. Finally, LED bulbs operated remotely within a smart home automation scheme eliminate the need for wall switches.
Big savings in big cities
The largest users of lighting are obviously the ones to benefit most. That fact isn’t lost on cities where electricity can represent 40% of its budget, so lighting is typically the first item on the list to become “smart.” Replacing high-pressure sodium (HPS) and metal halide bulbs with LEDs saves hundreds of thousands, even millions of dollars annually. LED lighting can also last four times longer than HPS lamps, which reduces maintenance costs. Because they’re wirelessly connected to each other and to the city’s network, they can become part of its “smart city” IoT infrastructure. That way, failures can be immediately detected, and each streetlight can be turned on and off depending on conditions.
After deploying LEDs, a city can mount sensors such as cameras and acoustic sensors and connect them all to the network, providing massive amounts of data never previously available.
Cities that have availed themselves of this data bonanza face controversy since not everyone is happy having government and its police force spying on them (China comes to mind). The debate is increasing as more smart lighting is being deployed, and the result in most cases has been for advocates and the opposition to compromise.
Beyond just providing white light, the LED has also had an immense impact on vertical farms that serve the agriculture market by allowing crops to be grown year-round. Not only are the farms more productive, but rows of plants or vegetables can be stacked. This wasn’t possible using fluorescent or other bulbs because they generated too much heat. Stacking results in more than 10 times the crop yield per acre over traditional methods and increases productivity of the farmed acreage by a factor up to six and as high as 30. Varying the color spectrum can also enhance the productivity of plants. No one will soon be vertical-farming corn, but LEDs have distinct advantages for other markets.
Make money, save the planet
Large users of LEDs are just beginning to realize that in addition to saving money by reducing their use of electricity, they’re also saving the planet and can profit from carbon credits or offsets. A carbon credit is basically a permit that allows an entity to emit a certain amount of carbon dioxide or other greenhouse gases. If the entity suddenly has more credits than it can use, it can sell them to someone else, which provides an incentive to reduce greenhouse emissions and saves even more money.
Like all regulations, carbon offsets are complex. In general, they’re all based on an LED bulb’s reduced energy consumption over its lifetime. The total pounds of CO2 reduced is the number of kilowatt-hours saved multiplied by the pounds of CO2 produced per kilowatt-hour. The formula for determining this is much more complicated because each state’s power sources are different, but the incentives can be immense, as demonstrated by Tesla.
The auto industry’s exhaust emissions holy grail is the zero-emissions vehicle (ZEV), and the only way to achieve this is for the vehicle to be completely electric. At the moment, only Tesla can make that claim. In just the first quarter of 2021, the company added $518 million to its bottom line from sales of regulatory credits. As most other automakers committed to becoming all-electric before 2030, they too can cash in on this windfall – assuming the credits remain in place. However, the auto industry is just one example; any entity that meets the requirements can claim carbon credits.
LEDs take on disinfection
In addition to providing light in the visible spectrum, LEDs have recently become available that produce light in the ultraviolet spectrum – invisible to the human eye – that lies between X-rays and visible light. Within these spectral regions (UVA, UVB and UVC), the latter has shown its ability to kill bacteria and viruses when used in surface, air and water purification.
The primary light source has been the mercury-vapor lamp, which emits all three UV bands and makes them harmful to human presence. Also, concerns over their effects on the environment have restricted use to existing, safety-designed fixtures that the U.S and in the European Union will ultimately ban. Although mercury-vapor lamps are being replaced by metal halide lamps in the enormous number of places where used, UVC LEDs may be an appealing alternative now that they are available.
However, UVC LEDs are a new technology and their efficacy for disinfection is much lower than legacy lighting. This is typical for any new technology. The need for a solution increased because of the pandemic. UVC radiation can inactivate the reproduction of the SARS coronaviruses. Multiple studies show that it is effective against SARS-CoV-2. Testing is continuing to identify the dose and duration of UVC radiation required to inactivate it. As more studies appear and UVC LEDs advance in their capabilities, they will be a formidable antivirus solution.
The versatility of LED lighting also makes it a natural fit for use with Power over Ethernet (PoE), which is quickly gaining acceptance in large building such as hotels. Unlike incandescent lighting that is basically a fixed light source with no ability to be controlled, LED lighting combined with PoE provides a single cable to deliver both low-voltage DC power as well as high-speed data communications.
Not only does this eliminate AC-to-DC power conversion within each lighting fixture, it improves building efficiency by significantly reduced costs associated with wiring infrastructure. PoE can support not just lighting control but any other type of low-voltage device such as a smart door lock, meeting-room video cameras and Internet access for Wi-Fi. In places where the approach has been deployed, PoE-based LED lighting has already demonstrated its benefits.
