New Technologies: Wireless Power
New technologies are changing global energy system and there will be a time where physical energy infrastructures won't exist anymore because of wireless power, which is the transmission of electrical energy from a power source to an electrical load without man-made conductors. Can we really send Watts of energy as we send an email? Apparently yes and the advantages are endless. Think about the amount of money spent in energy infrastructures (pipelines, electricity cables...) and think how much energy can be shared in the world. There are many ways to transmit power without wires. The most common form of wireless power is carried out using direct induction followed by resonant magnetic induction. Other methods are laser and microwave transmission (which I mentioned regarding space-based solar power) and electrical conduction throguh natural media.
Electromagnetic induction is an effect on which are based all the machines which transform mechanical energy into electricity. This is the specific field of Mr. Tesla, inventor and father of wireless power. In a few words: energy is transformed into a magnetic field and transfered from one bobine to another and then it turns into electricity again. This principle is applied into a larger scale.
For longer distances the most efficient method is microwave transmission which consists in converting energy into microwaves and send them to an antenna called rectenna that converts them into energy. Rectenna conversion efficiencies exceeding 95% have been reached. This is the method that is going to be used in space-based solar power. Still, this method has some disadvantages due to the excessive diameters of the antennas (in space they have a 10 km diameter and on Earth a 1 km one) but with a continuing research they'll be reduced. Another problem could be caused by atmosphere that could stop microwaves. Connecting the space and the Earth is a difficult problem to solve but on our planet microwave transmission is the best way for wireless power.
Power can also be transmitted by converting electricity into a laser beam that is then pointed at a photovoltaic cell. This mechanism is generally known as "power beaming" because the power is beamed at a receiver that can convert it to electrical energy. Laser power presents different advantages than other methods but laser radiation is hazardous. Low power levels can blind humans and other animals. Conversion between electricity and light is also inefficient. Photovoltaic cells achieve only 40%–50% efficiency.
The wireless transmission of alternating current electricity through the Earth uses the possibility of electricity to be transmitted through determined subsurface layers, for example, from one ocean to the other, thanks to the presence of certain minerals which determine a low loss of electricity during the transfer. This method can be applied in the air as well.
This kind of transmission could bring to four great changes in energy system:
1. Energy sharing; one of the greatest problem of our time is the inequality of energy distribution in the world. Wireless power would allow to send energy where physical infrastructures can't arrive. It would allow to send energy where it can't be produced.
2. Connecting sources and consumers. There are places where energy can't be produced (like space) and it would be impossible to ship the energy produced there to the consumers unless wireless power is used.
3. Avoiding physical infrastructures incidents. For too much time we saw disasters such as oil spills on the land and in the sea causing tremendous damages to the environment. With wireless power these spills will stop.
4. Extromission of fossil fuels. One of biggest disadvantages of fossil fuels is the high transport cost. Think to the oil trains and the ships and the pipelines. All these costs make fossil fuels expensive and obsolete. Renewable energy can be easily converted into electricity and with wireless transmission can be shipped at a low cost.
Besides, I will be tremendously happy when I'll see fossil fuels decade.
This revolutionary idea is being experimented but soon it will become operative and another step to a faster and efficient energy system will be done.
Photo from ESO (European Southern Observatory).
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