Wireless electricity: Goodbye to cables

Our homes are getting smarter: You can switch on a light with your voice, you can programme the coffee machine to have your drink ready every morning, you can sit on the sofa and watch the robot vacuum cleaner leave the floor perfectly clean and the fridge can even warn you that you are running out of milk. What will be the next step forward? To be able to charge your mobile phone or turn on the television without having to use cables.

Wireless data transmission via Wi-Fi or Bluetooth networks is almost universal nowadays: Practically nobody even thinks about using a cable to send an image between two mobile phones or to connect a computer to the router. The same goes for wireless electricity which would eliminate the need for cables or other physical connections to supply power to devices and systems efficiently through the air or other means. Its uses, which in some cases are already applicable, range from comfort in the domestic environment to medicine and industry. 

How does wireless energy work?

The concept of wireless power involves a number of technologies that enable electricity to be transmitted wirelessly. The great inventor of the 20th century, Nikola Tesla, already dreamed of the wireless transmission of electricity over long distances, using only an electromagnetic field in the air.

Today we know that the starting point is based on two different typologies: Radiative and non-radiative.

• Non-radiative wireless power transfer, or near-field, are the best known. In this case, magnetic fields are used to create magnetic coupling between electrons, inducing electric currents in receptor devices equipped with resonant coils. This enables the transfer of energy over short distances and it is especially used in devices such as electric brushes, smart cards, etc.
• Wireless radiative energy transfer, or radiant energy, energy is transmitted by radiation beams, such as microwaves and lasers. This has a much longer range than the previous one but the waves need to be directed at the receiver. They are commonly used in satellites and unmanned aerial vehicles.

All wireless power applications

1. Wireless power has the potential to revolutionise a number of industries and make daily life more comfortable and efficient. As this technology continues to advance, numerous uses and applications are being explored in a number of different fields:
2. Charging electronic devices: One of the most obvious uses of wireless power is to charge electronic devices like mobile phones, tablets and computers. Wireless charging is really practical as it can be done without cables, and it is much more comfortable and orderly.
3. Electric vehicles: Wireless power could be key to charging electric vehicles more efficiently and comfortably. This technology would greatly expand the options for charging cars, as they can be recharged wherever they are parked or even while travelling along the road. This would increase the autonomy of electric vehicles and reduce the need to stop at charging stations.
   
4. Medical devices: In medicine, wireless power could be used to charge implantable medical devices like pacemakers and neurostimulators. This would eliminate the need for repeated surgeries to replace batteries and improve patients' lives.
   
5. Domestic appliances and the smart home: With wireless power, plugs and tangled up cables will be a thing of the past. It will make it easy to charge and use both domestic appliances. This will contribute to the expansion of smart home systems and the simplification of device management.
   
6. Urban infrastructure: In urban environments, wireless power could be used to power sensors, street lighting, traffic lights and other devices in public areas. This could reduce the cluttering of cables and make it easier to implement "smart city" technologies with the resulting reduction of maintenance and installations.
   
7. Manufacturing industry and automation: In industry, wireless power could enable the power to be provided for sensors and devices in places that are hard to reach and harsh environments which will improve the monitoring of processes and automation.
   
8. Emergency communications: When there are natural disasters or emergencies, wireless power could be used to charge communication devices and keep communication lines open even in the absence of electrical infrastructure.
   
9. Space research and satellites: In space, wireless power transmission could be used to power satellites and space probes, eliminating the need to replace batteries or cables in the vacuum of space.
   

The future of wireless electricity

There are currently many companies and start-ups that are innovating with a view to meeting the main challenges and making wireless energy an accessible reality for everyone.

There is no doubt that the main challenge is long-distance transmission efficiency. As the distance between the sender and receiver increases, transfer efficiency decreases which restricts its usefulness in applications that require long-distance power transmissions.

Other significant issues are electromagnetic interference from other nearby electronic devices, the standardisation and operability of technologies and the impact that prolonged exposure to electromagnetic fields may have on human health.

Start-ups like the New Zealand company Emrod and Reach Power in Silicon Valley are doing all they can to meet these challenges and make wireless energy an integral part of our world. Another example is Witricity, a corporation focussing on innovation with more than 1,300 patents with regard to the development of the technology to transfer electricity wirelessly in a number of fields.