Wireless Power Transmission

Wireless energy transfer or wireless power transmission is the process that takes place in any system where electrical energy is transmitted from a power source to an electrical load, without interconnecting wires in an electrical grid. Wireless transmission is ideal in cases where instantaneous or continuous energy transfer is needed, but interconnecting wires are inconvenient, hazardous, or impossible.
Though the physics of both are related, this is distinct from wireless transmission for the purpose of transferring information (such as radio) through waves, where the percentage of the power that is received is only important if it becomes too low to successfully recover the signal. With wireless energy transfer, the efficiency is a more critical parameter and this creates important differences in these technologies

Introduction
Wireless is one of those hot tech catch-all of the new millennium. There are wireless broadcasters and receivers, utilizing such technology as WiMax, 802.11n, and Bluetooth. There are wireless gaming controllers. There's just about wireless everything -- except power transmission.

Wireless power transmission is something that inventor Nikolai Tesla came up with over a century ago and claimed to have perfected. However, his mysterious work vanished with his death, and for decades the


topic was left untouched. Now there has been resurgence in interest with several
Companies competing to becoming the first to offer commercially broadcast wireless power.
The new tech was first developed by Massachusetts Institute of Technology physicist Marin Soljacic. Professor Soljacic came up with the idea of transmitting wireless power via resonant magnetic fields. He calls the invention WiTricity, a blend of the words wireless and electricity. The work relies heavily on the electric concept of induction. Induction is already used commercially on a limited scale, to recharge certain powered toothbrushes.

Intel helped improve upon MIT's design, bringing the efficiency up from 50 percent to 75 percent. Internally, Intel is speculating that the device may permit and work with the shift from batteries to super capacitors. While currently more expensive, super capacitors could allow faster recharging. Mr. Rattner states, "In the future, your kitchen counters might do it. You’d just drop your espresso maker down on them and you would never have to plug it in."

Intel calls its new technology a "wireless resonant energy link". It uses transmitting loop antennas, less than 2 feet in diameter.

It is competing with a couple scrappy startups, which are also looking to improve upon MIT's technology. Startups Wild Charge, based in Boulder, Colo., and WiPower, based in Altamonte Springs, Fla. both are looking to make their name in wireless power history. While both have announced consumer devices based on their upcoming technologies, their devices currently require the item to be touching the transmitter.
Application in space (transmitting solar power):
Space Solar Power gathers energy from sunlight in space and transmits it wirelessly to Earth. Space solar power can solve our energy and greenhouse gas emissions problems. Not just help, not just take a step in the right direction, but solve. Space solar power can provide large quantities of energy to each and every person on Earth with very little environmental impact.
The solar energy available in space is literally billions of times greater than we use today. The lifetime of the sun is an estimated 4-5 billion years, making space solar power a truly long-term energy solution. As Earth receives only one part in 2.3 billion of the Sun's output, space solar power is by far the largest potential energy source available, dwarfing all others combined. Solar energy is routinely used on nearly all spacecraft today. This technology on a larger scale, combined with already demonstrated wireless power transmission can supply nearly all the electrical needs of our planet.
Another need is to move away from fossil fuels for our transportation system. While electricity powers few vehicles today, hybrids will soon evolve into plug-in hybrids which can use electric energy from the grid. As batteries, super-capacitors, and fuel cells improve, the gasoline engine will gradually play a smaller and smaller role in transportation — but only if we can generate the enormous quantities of electrical energy we need. It doesn't help to remove fossil fuels from vehicles if you just turn around and use fossil fuels again to generate the electricity to power those vehicles. Space solar power can provide the needed clean power for any future electric transportation system.
While all viable energy options should be pursued with vigor, space solar power has a number of substantial advantages over other energy sources.
Advantages of Space Solar Power
• Unlike oil, gas, ethanol, and coal plants, space solar power does not emit greenhouse gases.
• Unlike coal and nuclear plants, space solar power does not compete for or depend upon increasingly scarce fresh water resources.
• Unlike bio-ethanol or bio-diesel, space solar power does not compete for increasingly valuable farm land or depend on natural-gas-derived fertilizer. Food can continue to be a major export instead of a fuel provider.
• Unlike nuclear power plants, space solar power will not produce hazardous waste, which needs to be stored and guarded for hundreds of years.
• Unlike terrestrial solar and wind power plants, space solar power is available 24 hours a day, 7 days a week, in huge quantities. It works regardless of cloud cover, daylight, or wind speed.
• Unlike nuclear power plants, space solar power does not provide easy targets for terrorists.
• Unlike coal and nuclear fuels, space solar power does not require environmentally problematic mining operations.
• Space solar power will provide true energy independence for the nations that develop it, eliminating a major source of national competition for limited Earth-based energy resources.
• Space solar power will not require dependence on unstable or hostile foreign oil providers to meet energy needs, enabling us to expend resources in other ways.
• Space solar power can be exported to virtually any place in the world, and its energy can be converted for local needs — such as manufacture of methanol for use in places like rural India where there are no electric power grids. Space solar power can also be used for desalination of sea water.
• Space solar power can take advantage of our current and historic investment in aerospace expertise to expand employment opportunities in solving the difficult problems of energy security and climate change.
• Space solar power can provide a market large enough to develop the low-cost space transportation system that is required for its deployment. This, in turn, will also bring the resources of the solar system within economic reach.
Disadvantages of Space Solar Power
• High development cost. Yes, space solar power development costs will be very large, although much smaller than American military presence in the Persian Gulf or the costs of global warming, climate change, or carbon sequestration. The cost of space solar power development always needs to be compared to the cost of not developing space solar power.
Requirements for Space Solar Power
The technologies and infrastructure required to make space solar power feasible include:
• Low-cost, environmentally-friendly launch vehicles: Current launch vehicles are too expensive, and at high launch rates may pose atmospheric pollution problems of their own. Cheaper, cleaner launch vehicles are needed.
• Large scale in-orbit construction and operations: To gather massive quantities of energy, solar power satellites must be large, far larger than the International Space Station (ISS), the largest spacecraft built to date. Fortunately, solar power satellites will be simpler than the ISS as they will consist of many identical parts.
• Power transmission: A relatively small effort is also necessary to assess how to best transmit power from satellites to the Earth’s surface with minimal environmental impact.
All of these technologies are reasonably near-term and have multiple attractive approaches. However, a great deal of work is needed to bring them to practical fruition.
In the longer term, with sufficient investments in space infrastructure, space solar power can be built from materials from space. The full environmental benefits of space solar power derive from doing most of the work outside of Earth's biosphere. With materials extraction from the Moon or near-Earth asteroids, and space-based manufacturer of components, space solar power would have essentially zero terrestrial environmental impact. Only the energy receivers need be built on Earth.
Space solar power can completely solve our energy problems long term. The sooner we start and the harder we work, the shorter "long term" will be.


Areas of Future use:
The advantage of this technology is it can transmit power even when not in contact. And the receiver antenna is about the size of a laptop base. It could be that cell phones and P.D.A.’s are even more compelling and it would be more useful for laptops.
In robotic technology, sensors using the power transmission and reception technologies could use electric fields to detect objects.
Transmission of Information -it would not interfere with radio waves and thus could be used as a cheap and efficient communication device without requiring a license or a government permit.