Uploaded on 2017-03-13 by Hossam Nada

The two pictures were taken by me. They display the platform area of a sub-way station in Cairo, Egypt. I chose a low density [few people] timing to give enough space for the visible elements to show [be visible in the picture]. The visible information are the subway carts, the platforms, the passengers, people waiting / walking along the platform, platform floor tiles, wall tiles, beams, ceiling, electrical conduits, ventilation ducts, lighting fixtures and artificial light. The two invisible information of choice are, in my opinion, [1] the kinetic energy dissipating from walking people's footsteps into the floor tiles and [2] the air quality. Considering the kinetic energy. I had always thought about the possibility of installing *piezoelectric tiles* to cover the floor [all the floor / effective areas of the floor] of the city's public areas that have a large number of people frequently walking around. These special tiles are small electricity generators. They turn the kinetic energy from people's footsteps into electric energy which can be used in different types of applications. This will reduce the demand on electrical power stations supplying electricity to the whole city [often using combustible fuels]. It's, thus, a clean, green, free & effortless [no one is required to exert any extra effort specifically for the purpose of producing electricity] source of energy that helps make the city more energy efficient and the environment cleaner. However, I have seen on different occasions how, in my country, such suggestions/proposals are often rejected based on the claim that the cost of applying such solutions will probably exceed the benefits. This claim is not supported but it is rarely argued against because of lack of information that can be combined to produce knowledge about the proposal's true potential. The tiles are expensive to buy / make & to install but we can not with certainty say that this high price makes the proposal / project useless until we actually calculate [in numbers] the amount of energy that can be [potentially] produced and therefore calculate the amount of money that will be saved [by producing this amount of energy for free instead of electrical power stations & combustible fuels]. With the help of visible information such as the average number of people flowing in & out of each station & the average number of people flowing in & out of the carts at different times of the day & on different days through out the week [by observation via special cameras and / or the already existing entrance & exit roller machines] in addition to certain visible measurements such as the distance between a certain cart door and the closest exit. Using these visible information, & applying certain laws of mechanics; the value of kinetic energy [in joules] produced by people's footsteps, the invisible information, can now be calculated / estimated [using simulation software]whether throughout the day or throughout the week therefore it is now possible to calculate / estimate [again using simulation software] the potential daily / weekly joules of generated electrical energy We can repeat the above simulation & calculations / estimations using different configurations for the tiles [having the tiles cover the whole floor or certain parts of the floor that are most effective [most frequently stepped on [this can also be visibly observed]] & based on this, for each of the different tile configurations & for each specific subway station, we can calculate / estimate the amount of money saved by the free electric energy being produced versus the cost of buying / making and installing the tiles and choose the best option or decide with a level of certainty that this project is as claimed, useless [of no real benefit].