Transfer electricity wirelessly
I have always dreamed of such technology. Imagine a world without any wires. If the electrical energy transmitted at light speed with high-efficiency, then we can charge all our electrical appliances anytime, anywhere, without the hassle of finding a charger. We can actually power deep space telescope or probes outside the solar system after their electrical reserves used up. The possibility is endless.
How I thought about this idea
I already have the thinking about this concept when I was in secondary school. I thought that if the data transmitted wirelessly through radio waves to hand phones, TV, and radio, why the electrical energy cannot transmitted in the same way? I imagined a completely wireless world where we just need to left our electrical gadgets everywhere and anytime for recharging and it is always fully charged when we decided to use it. The misalignment and twisting of large number of wires will be permanently resolved. This will be a hassle free world. I think that this technology is so advanced that I cannot figure it out.
One day, this idea came again into my mind and I decided to give it a try on Google. To my surprise, the internet is full of materials about this technology and the idea of this technology was already well-established in the 19th century by Nikola Tesla. He had a dream of transmitting electrical energy all around the world wirelessly. You can see yourself the portrayal of fictional Tesla coil in the movie "Sorcerer's Apprentice (2010)" that can produce music.
The simpliest way of wireless electrical transfer
I later discovered that the "inductive coupling" mechanism employed by transformers is the simplest means of wireless electrical transfer. This device used to step up or step down a voltage while changing magnetic fields produced by one coil can induce electric current on the other coil. What a fool I am! I learned this device during my secondary school!
Short range transmission
Although the Tesla's ambitious attempt was unsuccessful (we still use cables for transmission today), this concept employed in some of the gadgets of our daily lives. The most common example is our electric toothbrush. It recharge itself through inductive coupling. This method of transmission can prevent water from seeping into the electrical components of wet toothbrush. The main weakness of this method of transfer is its short transmission range. Other devices that use the same principle to charge batteries include "Slashpower recharging mat" and "Wildcharge metal pad" that can recharge multiple devices at once. (News) With inductive coupling, recharging pacemakers and artificial hearts has become easier as you do not need to open up a patient's body just to recharge their medical devices! However, the coil used for receiving wireless energy over a few meters range can make the gadgets less portable.
Other researchers are also interested to follow-up the work of Tesla including Massachusetts Institute of technology (MIT) researchers where they successfully powered a 60 Watts light bulb located over 2 meters away with 40% efficiency in 2007 by using resonant energy transfer, another method of transmission. (News) Canada's Communications Research Centre also created an airplane that powered entirely by the electrical power beamed from the earth in 1980s. More importantly, it can fly for months at a time! (News) Just in 2008, Intel has demonstrated the 75% efficiency transmission over two feet distance to power a 60 Watts light bulb. (News)
Some items that you may be interested in
Wireless charging mat for your mobiles on condition that you must plug in the Qi adapter into your mobile
Oral B electric toothbrush that uses inductive coupling for charging batteries.
If you want to know more about Nikola Tesla, then this is the book that you would want to read! This book details on the challenges that he faced for his invention of wireless electricity,
Wireless electrical transmission is actually a reality in our daily lives. But to expand it further, especially for the long-range transmission, is extremely difficult! There are claims where political factors have hindered the usage of this technology for the today world.(News) There are also speculations about the possible interference of this transmission with other data transmissions like TV radio waves. The usage of high frequency radio and microwaves also produce questions about the biological effects on all living things on the earth. (News)
If this long-range transmission is possible in the near future, their benefit is enormous. Wireless method of transfer is have high transmission efficiency. The cost of building poles, cables, and towers eliminated completely. This will cut down the monthly electricity bill for the consumers. Electricity supply for rural or underdeveloped areas will become much easier. There will be no interruption of electricity supply in areas bombarded with natural disasters.
To put it into a wider scale, the solar energy from space directed to the consumers on earth via microwaves, solving the inconsistency of electrical supply during cloudy or windy days. However, the size of rectenna (rectifying antenna, a special antenna for wireless electrical transfer) required to receive such electrical power will be large. Given that human safe electromagnetic exposure density is 1mW/cm2, such large rectenna will be a definite need to harness enough electrical energy while keeping a safe transmission. Here is the quote from EION wireless: "FCC and ETSI Guidelines for Human Exposure to Radio frequency Electromagnetic Fields (OET Bulletin 65) Limit is 10W/m2 or 1 mW/cm2" (Link).
Problems with long-range transmission
Rectenna will take up so much space that intended for real estate development or food crop plantation purposes. Although rectenna with mesh-like network used to allow sunlight and rain water to reach the ground, (Link) but how much such height limitation and the altering of magnetic fields will affect plantation in the long-term remains unknown. So which one should have the higher priority? Satellites specially designed for power transmission would be needed for comprehensive electrical coverage for all around the world. Such transmission will be very much in demand for pumping water resources under the Sahara desert in Africa and for aluminum smelting industries. It can also used for transmitting power into areas that are difficult to reach such as deep-sea vessels.
As the world demand for electrical supply continue to grow, I think that such method of long-range electrical transfer may become a necessity and not an interesting idea in the future. Solving specific problems with such electrical transfer is necessary before it commercialisation of such technology takes place. The idea of such transmission remains as a debatable issue and it needs the consensus of the entire human population to materialize such option of electrical transfer. So, what do you think about wireless electrical transfer? Should it become the key of the future power grid?