Running head: WIRELESS POWER TRANSFER 1

Wireless Power Transfer: Past, Present, Future and the Impacts of Wireless Technology

Running head: WIRELESS POWER TRANSFER 2
A common question asked of wireless power transfer is “Is it safe”. In the beginning, early press described this technology as being “electricity in the air” which contributed to heightening the fears of the public. The general public was under the assumption that wireless power could possibly expose them to huge amounts of dangerous electromagnetic fields when using these systems. Through proper design it is possible to keep stray electric and magnetic fields well within the same recognized human safety limits that regulate all electromagnetic consumer devices to include cell phones, wireless routers, Bluetooth headphones, etc. (Kesler, 2013).
Safety limits for human exposure to electromagnetic fields is established through a continuous review of scientific evidence of the impact these fields have on human health (Kesler, 2013). In the near future, the World Health Organization is projected to issue its own guidelines for human exposure limits to electromagnetic fields. Until those guidelines are released, the majority of national regulations, including the World Health Organization, reference the human exposure guidelines set forth by the Institute of Electrical and Electronic
Engineers and the International Commission on Non-Ionizing Radiation Protection. In the most recent reviews of scientific literature, both the Institute of Electrical and Electronic Engineers and the International Commission on Non-Ionizing Radiation Protection have concluded that there is no established evidence showing that human exposure to radio frequency electromagnetic fields causes cancer (Kesler, 2013).
There is however, recognized evidence that shows that radio frequency electromagnetic fields can increase human body temperatures, can heat body tissues and stimulate nerve and muscle tissues. The International Commission on Non-Ionizing Radiation Protection group has
Running head: WIRELESS POWER TRANSFER 3 also concluded that retinal phosphenes (a condition known as seeing stars) may be considered in determining human exposure limits (Kesler, 2013). In the case of tissue heating, both scientific groups have recommend limiting the specific absorption rate, a measure of the electromagnetic energy absorbed by the human body and turned into heat (Kesler, 2013). Both groups have also recommend that limiting the internal electric field would limit the likelihood of stimulation to nerve and muscle tissues as well as lower the chances of inducing retinal phosphenes. As a side note, the specific absorption rate and the internal electric field limits are referred to as “basic restrictions” because they are based on the physical quantities directly related to the established health effects (FDC, N.D.). In the case of tissue heating and body temperature increases, both groups have determined that the most sensitive human tissues are not adversely affected when the whole body averaged specific absorption rate levels are less than 4W/KG (Kesler, 2013). This corresponds to a maximum body temperature rise 1 °C under normal environmental conditions. As a cautionary step to compensate for incomplete scientific data, both groups recommend a whole body average specific absorption rate limit of .4 W/KG for workers in controlled environments (also called occupational exposure), and a limit of .08 W/KG for the general public.
With any new technology, a major concern for wireless power transfer are its indirect and/or direct environmental issues. Wireless power transfer could be a valuable technology from the environmental impact and associated carbon cost standpoint. As per the 1394 Trade
Association Technical brief, conventional external power supplies, chargers, and many other wall connected electronic devices use linear power supplies which are only about 30%-40%
Running head: WIRELESS POWER TRANSFER 4 efficient (Barman, 2009). Adding insult to injury, these electronic devices (when they are connected to electrical outlets) continue to consume electricity even when the device has been turned off. The combined cost of the 60%-70% wasted energy and the environmental impacts associated with it can be significant. Furthermore, the environmental cost of producing, packaging, distributing, and the end-of-life disposal of millions of conventional power supplies is also significant (Dittke, N.D).

PRODUCT | EMBEDDED ENERGY* | CO2 EMISSIONS** (Million Metric Tons) | #100 MW POWER PLANTS | Cell Phone | 21 | 4.2 | 7 | DECT Phone | 5 | 1.0 | 2 | Digital Camera | 2 | 0.4 | 1 | Set Top Box | 5 | 1.0 | 2 | Personal Care | 1 | .02 | 0 | Standard Battery Charger | 3 | 0.6 | 1 | Power Tool Charger | 4 | 0.8 | 1 | Printer | 4 | .08 | 1 | Lap Top | 2 | 0.4 | 1 | Other | 10 | 2.0 | 3 |
Table 2. Worldwide embedded energy to produce, ship, and dispose of external power supplies
* Total Energy Consumed for production packaging, distribution, and end-of-life disposal
**CO2 generation attributed to the energy generated by coal burning power plants to meet the embedded energy needs

As demonstrated by the chart above, wireless power transfer can play a key role in mitigating the environmental impact of producing, disposing, and end-of-life management of external power supplies, eliminating significant electronic waste. In 2008, 23% of the 3.2 billion external power supplies manufactured worldwide were shipped to the U.S. It is estimated that 400 million plus power supplies were retired that same year in the U.S., of which less than 20% were recycled. The remaining 80%-85% were disposed to land fields and incineration (Kamath, 2009). These power supplies were made of toxic materials with little to no salvageable components making them unappealing to recyclers. As evident from the previous statistics, Running head: WIRELESS POWER TRANSFER 5 wireless power transfer can have a key environmental-impact role in significantly eliminating electronic waste worldwide (Kamath, 2009).
Other than the e-waste that can be created from the wireless power transfer technology, it has been hypothesized that this technology can affect the environment in three ways: 1) localized environmental impact; 2) cumulative widespread impact; and 3) consequential impact (EPA, 2008). If a wireless power transfer device has any effect on the local environment it is considered a localized impact to the environment i.e. heat absorbed by physical objects due to the operation of the wireless power transfer device. Over time that heat may manifest itself as a negative impact. A cumulative negative effect could occur if widespread distribution of wireless energy causes a cumulative negative impact similar to water pollution; where overtime many localized sources of pollution could combine to have a devastating cumulative effect on the environment. A particular area of concern for this technology is its potential impact to the earth’s natural magnetic field. It has been theorized that disruption of the earth’s magnetic field could have unknown biological and environmental impacts (Kamath, 2009). The use of compasses would be affected since these devices use that field to locate magnetic north. The potential for localized environmental impact is one area where research would be helpful to identify potential risks and either eliminate them as a reason for concern or identify safe operating levels or other mitigation techniques (Kamath, 2009). A consequential impact is a natural follow on result of the existence and use of this technology. An example of the type of impact because of this technology is the long term effects of disposal of any hazardous materials from these devices. Some of the materials used to create the wireless power transfer technology is good for a one time use. After the life of these devices expire, we are now forced to find a Running head: WIRELESS POWER TRANSFER 6 long term disposal solution for these materials in a manner that would limit the possibility of these materials harming the environment. This type of disposal could become costly over time.
As stated before, wireless power transfer does have some negative impacts associated with its use but as impacts of this technology become better understood and upgrades in the designs are made, this technology could provide a superior alternative to the existing electrical grid system currently in use today.

Running head: WIRELESS POWER TRANSFER 7
REFERENCES
Barman, D. (2009). Making Wireless Truly Wireless: The Need for a Universal Wireless Power
Solution. Retrieved 2015 June 10 from: http://www.wirelesspowerconsortium.com/ technology/making-wireless-truly-wireless.html Dittke, S. (N.D.). The Health and Environmental Impacts of e-Waste. Retrieved 2015 June 10 from: http://inece.org/ewaste/01_dittke.pdf
Kesler, M. (2013). Highly Resonant Wireless Power Transfer: Safe, Efficient, and over
Distance. Retrieved 2015 June 7 from: http://www.witricity.com/assets/highly- resonant-power-transfer-kesler-witricity-2013.pdf Kamath, H (2009, December). Program on Technology Innovation: Impact of Wireless Power
Transfer Technology. Retrieved 2015 June 10 from: ttp://assets.fiercemarkets.net/public
/smartgridnews/000000000001020562.pdf
United States Environmental Protection Agency. (2008, July). Fact Sheet: Management of
Electronic Waste in the United States. Retrieved 2015 June 9 from the Environmental
Protection Agency website: http://www.epa.gov/epawaste/conserve/materials/ecycling
/docs/fact7-08.pdf