Energy demand
In an energy sensitive life style and with growing cost of energy, free energy from the air sounds like a fantasy. But scientists Nikola Tesla imagined this technology about 114 years before. These days, with more than half the world’s population with electronics gadgets’ of one or the other kind with them at every time—will like the idea of getting electrical power out of the air. A little over a century ago, the inventor Nikola Tesla drew up ambitious plans to transmit electrical power without wires. He carried out a series of experiments in which electric lights were illuminated via electrostatic induction, by connecting them to metal sheets suspended in a strong electric field produced by a distant transmitter. In 1898 he proposed a “world system” of giant towers that would form both a global wireless communications network and a means of delivering electricity over large areas without wires. The construction of the first such tower, the Wardenclyffe Tower, on Long Island, began in 1901. But before the tower was completed, spnsorer of the project pulled out as they worried that the delivery of electricity through the air could not be metered, and there would be nothing to stop people from helping themselves.We know a lot about how to manipulate electricity, but the way it forms naturally in the atmosphere has long stymied scientists.
We’re already making great strides at pulling electricity from the motion of the air and from the photons that stream through it, but what about pulling electric charges right out of the air itself? Researchers have solved a mystery about how electricity forms in the atmosphere, and in doing so may have found a way to pull electricity right out ofthe air. Even the smallest Internet-connected devices typically need a battery or power cord. Technology that lets gadgets work and communicate using only energy harvested from nearby TV, radio, cell-phone, or Wi-Fi signals is headed toward commercialization. The University of Washington researchers who developed the technique have demonstrated Internet-connected temperature and motion sensors, and even a camera, powered that way. We’re talking about free energy here: devices that never need charging, cost nothing to run, and aren’t limited by the location of an external power source. An entire smart city — where roads know when they’re busy and bins know when they’re full — could be devised using countless sensors that require no upkeep, and have no overheads beyond the price of the hardware itself. It’s a powerful idea, and beyond sensors, power from air (free energy) is imagined to be used to trickle-charge all kinds of hardware, significantly extending the battery life of a wearable, for instance. This can be scaled up for applications that require higher power outputs, and is currently being worked on miniaturizing its initial reference design and creating a flexible version that can be integrated into clothing, among other things.
Technology development
Transferring power wirelessly is not a new trick. But getting a device without a conventional power source to communicate is harder, because generating radio signals is very power-intensive and the airwaves harvested from radio, TV, and other telecommunication technologies hold little energy. The first product to use the energy system, a personal air pollution monitor, has been demonstrated. The technology, which has been patented, could now be used by organizations such as supermarkets which are preparing for the next phase of the internet, where billions of small cheap sensors are online providing data about their operations. Scientists and engineers have proved that weak radio signals can indeed provide all an Internet gadget needs, using a principle called backscattering. Instead of generating original signals, one of their devices selectively reflects incoming radio waves to construct a new signal. A gadget using the technique absorbs some energy from the signal it is modifying to power its own circuits.
One version of the University of Washington technology, dubbed passive Wi-Fi, is being commercialized. It lets battery-free gadgets connect with conventional devices such as computers and smartphones by backscattering Wi-Fi signals. In tests, prototype passive Wi-Fi devices have beamed data as far as 100 feet and made connections through walls. Doing that requires altering the software of a Wi-Fi access point to generate an extra signal for passive Wi-Fi devices to use, very slightly increasing its power consumption. It is reported that passive Wi-Fi consumes just 1/10,000th as much power as existing Wi-Fi chipsets. It uses a thousandth as much power as the Bluetooth LE and ZigBee communications standards used by some small connected devices and has a longer range. A device using passive Wi-Fi to communicate—for example, a security camera—could power its other circuits using energy harvested from the Wi-Fi signals it is backscattering, or by feeding on other signals such as TV and radio broadcasts. The researchers believe that tiny passive Wi-Fi devices could be extremely cheap to make, perhaps less than a dollar. In tomorrow’s smart home, security cameras, temperature sensors, and smoke alarms should never need to have their batteries changed. It can theoretically power a low-energy device forever, and for free.
We’re constantly surrounded by an ever-denser cloud of RF signals. They’re the reasons, smartphone gets 2G, 3G and 4G coverage, laptop gets WiFi, and TV receives digital broadcasts. Capturing energy from this background noise is nothing new, but most proof-of-concept scenarios have employed dedicated transmitters that power devices at short ranges. Furthermore, research into the field has never really left the lab, though a company called Nikola Labs is hoping to release an iPhone case that’s said to extend battery life using RF energy harvesting. It is claimed that the technology of free energy or power from air can be the power source for the “internet of things”, allowing low energy devices from wearable to sensors to operate without being plugged in. The technology involves harvesting radio frequency energy from existing wireless and broadcast networks, from 4G to digital television. It doesn’t require any extra infrastructure, it doesn’t require us to transmit any extra energy, it’s recycling the energy which isn’t being used at the moment.
Criticism
- The same thing could be achieved with a battery and low-power transmitter.
- Questions about the possible impact on the mobile networks, which own the spectrum, suggesting that that the “free” energy might actually be needed for communication.
- Others have tried the same idea, but have struggled to produce energy with enough efficiency to make the technology commercially viable.
- The amount of power can be harnessed depends on the density of ambient RF signals, which are way more prevalent in urban areas than the countryside.
- Power from air may well be the most efficient system of its kind, but it’s still only viable for devices that require very little power.
- In a location where lots of RF signals are flying around, like in an office, a standard free power unit can produce around 100 microwatts of power.
Acknowledgement: The use of information retrieved through various references/sources of internet in this article is highly acknowledged.
