Will Wireless Electricity Have A Sustainable Future?
The name Tesla probably makes you think of a pricey electric car or its larger-than-life eccentric CEO. No judgment, I think the same too. The name Tesla was inspired by the late 19th-century famed inventor and engineer, Nikola Tesla. The reason we are reminding you of your middle school physics teacher’s favorite scientist is his relevance to the history of wireless electricity. In 1902, Tesla envisioned and started building a wireless power delivery system that could power cities on the ground and planes in the air. By 2026, we expect this market to be worth over $13 Billion.
While wiring has been a reliable and convenient way to transmit power from one point to another, certain terrains and landscapes make the need for wireless transmission both for affordability and aesthetic purposes. According to interesting engineering, wireless transmission of electricity can be done in 6 ways:
- Inductive Coupling
- Magnetic Resonant Induction
- Electrostatic Induction
- Resonant Inductive Coupling
- Microwave Power Transmission
- Laser Power Transmission
While all these names may sound like gibberish, it should suffice to know that the first 4 of these only work for very short ranges. The most used wireless charging pads for smartphones and watches, called Qi-charging pads, are based on the principle of inductive coupling. While these charging pads provide a taste of true wireless charging, they suffer many drawbacks like the inability to move around with the device while charging, much slower than wired charging, etc.
Beyond the novelty factor of wireless electricity at short distances, effective use of this technology would only be justified if it can transmit to several locations that are otherwise inaccessible or if the recipient is in-motion. Radio waves are a great example of covering large distances as well as being accessible to in-motion recipients. Although we rarely give the radio a second thought, when a radio transmission is received, it triggers a small current in the receiver which is then translated into the sound we hear.
One of the biggest problems so far with long-distance transmissions is the loss of signal over distance as it is radiated in all directions. Emrod, a recently formed New Zealand-based company and covered by the Economist, is working on power-beaming electricity using narrow beams of targeted microwaves. Targeted beams should help reduce loss due to radiation and can focus on remote areas where cable lines may not be commercially viable. There are several risks and limitations involved with such an operation and Emrod seems to have planned for our two major concerns:
- The use of targeted microwaves is more commonly used to heat food and may not be entirely safe for humans. Emrod mentions that brief exposure to these beams should not be harmful to humans & animals, and the beams will be surrounded by “laser curtains” that will switch off the beam if anything passes through the curtain.
- Targeted beams are often limited to the line of sight but in this case, Emrod has created relays that don’t use power and act like lenses to refract the beams and send them in the intended direction.
Not to be left behind in the quest for sustainable energy, NASA developed the SPS Alpha project in 2012 to investigate the harvesting of solar energy and beaming it back to earth. Whether or not this gets implemented, time will tell, but until then remember to charge your smart devices and vehicle before you leave the door. Scotty will not beam you up if you get caught outdoors without juice!
