Power Transmission Through Lasers

Wireless power transfer has considerable advantages. The absence of transmission towers, overhead cables, and underground cables is the foremost among them, not to exclude the expenses saved in their installation, upkeep, and maintenance. However, one of the major hurdles to wireless power transmission is the range it can cover. But now, Ericsson and PowerLight Technologies have provided a new proof of concept project that uses a laser beam to transmit power optically to a portable 5G base station.

Wireless power transmission is not a new subject to many. People use wireless power for charging many devices like earbuds, watches, and phones. But the range in these chargers is short, as the user must place the device on the pad of the charger. This limits the usefulness of the wireless charging station for transmitting power. Although labs have been experimenting with larger setups that can charge devices placed anywhere within a room, reports of beaming electricity outdoors and for long distances have been rather scarce.

PowerLight has been experimenting with wireless power transfer for quite some time now, and they have partnered with Ericsson, a telecommunications company, for a proof of concept demonstration. Their system consists of two components, a laser transmitter, and a receiver. The distance between the transmitter and receiver can vary from a few hundred meters to a few thousand meters.

However, unlike a Tesla coil, the PowerLight device does not transmit electricity directly. Instead, at the transmitter end, electricity powers a powerful laser beam, sending it directly to the receiver. In turn, the receiver uses specialized photocell arrays to convert the incoming laser back into electricity for powering connected devices.

Such a powerful laser-blasting through the open air can be a dangerous thing. Therefore, PowerLight has added many safeguards. They surround the beam with wide cylinders of sensors that can detect anything approaching. The sensors can shut off the beam within a millisecond, if necessary. In fact, the safety system is so fast that a flock of birds is not affected when flying through the laser beam, but there is an interruption at the receiver.  To overcome such fleeting interruptions, and cover longer-term disruptions as well, the PowerLight system has a battery back-up at the receiver end.

PowerLight is using their system to power a 5G radio base station from Ericsson, that has no other power source connected to it. The base station received 480 watts from the transmitter placed at a distance of 300 m. However, according to the PowerLight team, the technology can send 1000 watts over a distance of over 1 km. They also claim there is room for future expansions.

Wirelessly powering these 5G units could make them more versatile, as they will then become portable, and capable of operating in temporary locations. This will also allow them to operate in disaster areas, where there has been a disruption of infrastructure.

According to PowerLight, their optical power beaming technology may be useful in several other applications also, such as for charging electric vehicles, in future space missions, and in adjusting the power grid operations on the fly.