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Where are we on our journey toward wireless power transmission?

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Christopher Neely's picture
Independent Local News Organization

Journalist for nearly a decade with keen interest in local energy policies for cities and national efforts to facilitate a renewable revolution. 

  • Member since 2017
  • 725 items added with 353,227 views
  • May 13, 2020

Ditching the wires is seen as ideal across the technology sector.  Not just the wires needed to operate the objects, such as in televisions or stereo systems, but also ditching the wires needed to charge the technology, such as cell phone or electric vehicles.

When it comes to wireless power transmission from energy grids, it’s actually theoretically possible, but we’re still far away from it being safe—we’ll get to that in a moment. However, wireless power transmission for electric vehicles or kitchen appliances has seen momentum lately and such technology could hit the market soon.

Figuring out wireless transmission for the small stuff—cars, appliances—will help society get closer to figuring out how to ditch the wires for the larger stuff—homes, energy grids. Could you imagine a world without heavy duty transmission lines? That carries major implications for wildfire and environmental safety. However, wireless transmission at that scale is still far away.

There have been recent advancements in wireless transmission at a small scale, however. At short distances of two- to-three-feet, researchers at Stanford University have figured out how to charge electric vehicle batteries while on the move. At a distance of 1 meter, they could charge EV batteries at 10W of energy. This is significant progress for cars, drones and robots.

According to SoMag News, the efficiency of this wireless transmission technology has improved greatly. Initially, though wireless chargers could transmit a charge as the receiver’s distance shifted, the technology still lost 90% of the energy that was running through the system, making it incredibly inefficient. The latest technology only loses 8% of the electricity.

Not only is the wireless transfer more efficient, but it can happen quickly. According to a report from New Atlas, the technology is to where 10W of energy can be transmitted in a fraction of the time it takes a car, traveling 70mph, to drive over a four-foot charging zone.

However, researchers don’t expect this to technology to be deployed on roads at first, rather, on warehouse floors to power robots and allow for continuous, wireless operation, or, “on rooftops so that drones can hop around cities all day, only stopping for a quick top up en route. For the moment though, the project remains in the lab.”

Cars, robots and drones is about as far as science has gotten in safely performing wireless transmission. These products can charge over short distances. The problem of longer-distance wireless charging remains an unsolved question, mainly due to health concerns. Sending energy long distances, such as, say, from an energy grid to a neighborhood, requires the use of microwaves, which are not safe for our health. According to research on the topic,  electromagnetic fields, such as the ones that massive microwave transfers would create, can cause cancerous cells to multiply.

Professor Ron Hui out of the University of Hong Kong and Imperial College London is working on this problem. His team is working on the “world’s first independent harvesting and power supply for smart grids,” according to a recent report from Power Technology. The system would transmit energy between transmission towers.

“It’s like a domino arrangement,” Hui told Power Technology. “We have all these resonators which will allow us to pass power one by one – and that will significantly improve energy efficiency. With this technology we can get energy efficiency over 60%.”

Wireless transmission is a problem being actively worked on in the energy sector. Removing unnecessary cables and wires reduces hazards that have plagued utilities will be a sought after advancement.

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Jim Stack's picture
Jim Stack on May 18, 2020

A great subject. This was an idea from Nichola Tesla that never made it to production. It has also been proposed for Solar from Space and it could be a big idea. But the inductive power we have today is not very efficient and is not high power. Qualcomm has been the leader. 10 kW is about the best so far. Most is used for cell phones but someday it may advance.

Matt Chester's picture
Matt Chester on May 19, 2020

Do you know if there are any risks as the wattage get larger? I imagine there would at least be fears of risk even if they weren't real (a la the concern some in the public have these days about 5G), so I wonder the best way to combat that right off that bat

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