Possibility of Energy Scavenging from the Earth's Electric Field

1. Possibility of Energy Scavenging from the Earth's Electric Field Eric Cartman, Larry Howard, Moe Howard, Curly HowardDepartment of Engineering and Physics, University of Central Oklahoma, Edmond, OK 73034 Background Experimental Setup Abstract Future Development It has long been known that the earth has an ambient electric field of approximately 100 V/m directed vertically downward. The possibility of energy scavenging and harvesting this ambient electric field is examined. Joule-Thief type circuits are used to examine this possibility. Work is planned for Summer 2009 to investigate the effect of receiving plates with different areas and made from different materials. In addition, the effect of plate orientation and height will be studied. This will hopefully give some clues as to the origin of the potential difference. A large capacity bank of capacitors will be developed to hopefully store energy and determine if the system has any practical viability as an energy source. The results of the ongoing project will be reported at future date. The earth’s surface carries a negative charge and the lower atmosphere has a positive charge resulting in a net downward electric field of approximately 100 – 200 volts/meter. In Fall 2008, a student research project was initiated to investigate the claims of the Tesla and Plauson patents and if verified to collect data in an attempt to identify the source of the ambient energy. The basic circuit tested is shown at right. The insulated antenna wire was connected to a 24” x 36” copper plate insulated by a laminated coating. Overview Energy Harvesting is the process of capturing minute amounts of energy from naturally-occurring energy sources, accumulating them and storing them for later use. Energy-harvesting devices efficiently and effectively capture, accumulate, store, condition and manage this energy and supply it in a form that can be used to perform a helpful task. Why Energy Harvesting? Advanced technical developments have increased the efficiency of devices in capturing trace amounts of energy from the environment and transforming them into electrical energy. In addition, advancements in microprocessor technology have increased power efficiency, effectively reducing power consumption requirements. In combination, these developments have sparked interest in the scientific and engineering community to develop more and more applications that utilize energy harvesting for power. Energy harvesting from a natural source where a remote application is deployed, and where such natural energy source is essentially inexhaustible, is an increasingly attractive alternative to inconvenient wall plugs and costly batteries. This essentially free energy source, when designed and installed properly, is available maintenance-free and is now available throughout the lifetime of the application. Such systems can be more reliable than wall plugs or batteries. In addition, energy harvesting can be used as an alternative energy source to supplement a primary power source and to enhance the reliability of the overall system and prevent power interruptions. McKenzie (1956) gives an excellent short account of this electric field and its variation and Feynman (1974) gives a vivid description of the basic physics. Tesla in a 1901 in a pair of U.S. patents, Apparatus For The Utilization of Radiant Energy and Method Of Utilizing of Radiant Energy describes an apparatus for scavenging what he terms “radiant energy” from the natural environment. In March 2009, a construction of the apparatus was completed to investigate the claims of the Tesla and Plauson patents and if verified to collect data in an attempt to identify the source of the ambient energy. The circuit shown above was constructed and the voltage across the capacitor bank was monitored for approximately three days after a two day period to allow the charge to build up. The results are shown in Figure 1 below. References • R.P. Feynman, et a1., The Feynman Lectures on Physics v01 2 (Addison Wesley, New York,1974) Chapter 9. • H. Plauson - "Conversion of atmospheric electric energy" U.S. Patent 1,540,998 ( • A.E.E. McKenzie, A Second Course of Electricity • (Cambridge University Press, Cambridge, 1956) Chapter 3. • N. Tesla, Apparatus For The Utilization of Radiant Energy, US Patent 685,957 (1901). • N. Tesla, Method of Utilizing Radiant Energy , US Patent 685,958 (1901). Tesla idea outlined in these patents was very simple: Referring to the diagram above, stick a metal plate, P, as an antenna in the air, the higher and the larger the plate area the better, and wire it to one side of a capacitor, the other going to a good earth ground, F, and the potential difference will then charge the capacitor, C. Connect across the capacitor a switching device, d-R, so that it can be discharged at rhythmic intervals, and you have an oscillating electric output. There is no record of Tesla ever having built the device, but in view of its simplicity and the resources he had available at the time, it would be surprising if he did not test it. Tesla believed that radiation of some sort from the sun or some other source impinged on the plate and charged the system. Hermann Plauson , the director of the "Otto Traun Research Laboratories" in Hamburg, Germany during the 1920s, built on Tesla's idea with a patent that describe methods to convert alternating radiant static electricity into rectified continuous current pulses. He claims to have made numerous measurement and reported some experimental results in his book "Production and Utilization of the Atmospheric Electricity" (Gr., Gewinnung und Verwertung der Atmospharischen Elektrizitat). Results Contact Information The voltages and charges obtained were low but may result from leakages and less than optimal grounding of components. There is reason to believe from the preliminary tests that sufficient power could be harvested using this or similar device to run low power device electronics. We were able to power a LED using Joule-Thief circuit using the described antenna system to harvest the required energy. There are reasons to believe the system could be scaled up.