InnoCentive Challenge Name: Lightning as an Alternative Energy Source
Doc. Number: (internal use only)
My Solution:
Detailed Description of the Solution
The Solver's novel idea for a potential alternative energy source is the "Atmospheric Charge Collection by a Skyscraper" as a system to extract electrical power from the Earth's ambient electric field.
It is known that large quantities of electrical energy are present in the atmosphere without lightning. Benjamin Franklin is said to have harnessed electricity in his famous kite experiment during a thunderstorm, and drawn sparks from a key tied to the string to a Leyden Jar. It is more likely that he actually harvested atmospheric charges instead of a lightning discharge .
Lightning is only a small part of the total electrical activity in the atmosphere. When a local build up of electrical charges above the ground exceeds the local breakdown potential of the atmosphere, a lightning discharge occurs. However, there is an invisible flow of electrical charges from the ionosphere to the ground occurring day and night over the entire surface of the globe, which far exceeds the global lightning power output by many times. It is this flow that can be tapped and directed to provide useable electrical power. Thus, atmospheric charge flow has continuous low energy density as opposed to instantaneous super-high energy density of lightning.
Energy (E) = Power (P) * Time (t) = Voltage (V) * Current (I) * Time (t)
The proposal is to install an atmospheric charge capturing system on the surface of a skyscraper. Such an atmospheric-charge system would capture much less peak energy than a lightning system would do, but it would capture electrical charges continuously day and night. As the atmospheric charges are constantly drained into the atmospheric charge capturing system , there will be fewer lightning strikes that cause deaths and damages. The analogy is filling a swimming pool with steady drops of tap water leaking from a faucet over time .
The natural electrostatic potential gradient between the ionosphere and the ground is in the order of about 100 V/m near the surface in summer, and about 300 V/m in winter. It is well known that electrostatic motors can be driven by such atmospheric electric field indefinitely from an appropriate antenna and ground connection. As the electric charges flow down to the ground, the ionosphere is replenished by the solar wind.
To convert this electrostatic potential field into useable electricity, an antenna or collector is raised to a suitable altitude. The essence of capturing atmospheric electricity in DC current is to utilise the natural electrostatic potential gradient of the Earth to electrically charge a bank of super-capacitors or batteries. Electricity is then withdrawn from the super-capacitors or batteries and fed to the load as required.
Alternatively, the DC current can be converted to an AC current in real time by a power inverter (DC-to-AC power converter). Also, the DC current can generate dihydrogen (H2) fuel by electrolysis of water (H2O).
Here are documented advantages of atmospheric electricity.
simple and robust technology with no moving parts
low-cost technology, i.e., cheaper than photovoltaics or wind turbines
available day and night in all weather conditions
in fact, more power is produced at night than during the day
available at any point on the Earth's surface
Each of the Seeker's Technical Requirements and Desirable Properties is addressed as follows.
Capture of atmospheric-charge current takes place at the non-grounded conductive surface of a skyscraper with a curtain-wall construction, specifically at the aluminum-alloy window panes and gold-coated window glass. In commercially-available "Sun-Insulating Window Glass" which is used in many modern office buildings to block infrared radiation, homogeneous and continuous gold film is applied to the window glass by vacuum evaporation or vacuum sputtering. Thanks to much lower voltage of atmospheric charges than that of lightning, material erosion of the electrode will not be a problem.
Transfer of atmospheric-charge current from the non-grounded conductive surface to the electrical load requires an electrically continuous window pane/window glass and an insulator gap at the bottom of the skyscraper. During the non-lightning condition, atmospheric charge flows in continuous current through the curtain wall of the skyscraper. Electrical insulation is best achieved by electrically-insulating structural material like polytetrafluoroethylene (PTFE) which is commonly known as Teflon™.
Switching of atmospheric-charge current between the non-lightning condition and the lightning condition is automatically made thanks to the standard grounded lightning rod at the centre of the skyscraper. During a lightning strike, the cone of protection automatically shields the conductive surface of the skyscraper from mega-amperes of current.
Storage of atmospheric-charge current is achieved by charging a bank of super-capacitors or batteries. Since the voltage of atmospheric charge is much lower than that of lightning, dielectric breakdown of the equipment is not a problem. Also, material erosion due to lightning-induced mega-amperes of current is not a problem. Moreover, there is no problem of voltage reversal.
Experimental Section
Literature search revealed that an experiment carried out in the 1920's obtained an electrical power output of between 0.72 kW and 3.4 kW from 1 and 2 aerostats 300 m above ground level. The aerostats were manufactured from magnesium-aluminum alloy, covered with electrolytically deposited needles.
Many modern skyscrapers are taller than 300 m, and their windows are often coated with gold (Au) in order to block infrared radiation (IR). This would dramatically enhance the power output because the total atmospheric charge collected is proportional to the surface area. The key challenge of the proposed concept is to find or make an insulating gap in existing skyscrapers. It may be easier to negotiate such a design modification prior to the construction of a "super-green skyscraper".
As a pilot project, a conductor may be run from the observation deck of a concrete-frame tower (e.g., the CN Tower of Toronto, ON, Canada). Technological feasibility study of retrofitting existing infrastructure of skyscrapers may be conducted.
Please note that the Solver is willing to lead a team to conduct proof-of-concept experiments, and then to implement the novel Atmospheric Charge Collection by a Skyscraper, as the Seeker sees fit.
References and Notes
Atmospheric Electricity Research
<http://www.meridian-int-res.com/Energy/Atmospheric.htm>
Feasibility of tapping atmospheric charge as a power source
Author: Breuer M.L. (University of Massachusetts)
Source: Renewable Energy, Volume 28, Number 7, June 2003, pp. 1121-1127(7)
Publisher: Elsevier
Gewinnung und Verwertung der Atmosphärischen Elektrizität
Author: Plauson, Hermann
Source: 1920
There is no patent art preventing the use of materials, equipment and methods for the proposed application. Patent application "Atmospheric Charge Collection by a Skyscraper" is being drafted by the Solver for potential exclusive licensing to the Seeker.
Please note that the Solver is willing to serve as a consultant to the Seeker in order to co-operatively achieve full commercialisation of the technology.
Conclusion
The proposal is a paradigm shift of the conventional idea for capture, transfer, switching and storage of electrical lighting discharges. The Solver believes that the novel Atmospheric Charge Collection by a Skyscraper will meet all of the Seeker's Technical Requirements and Desirable Properties.
