Global Issues Blog: The (False?) Promise of Kinetic Energy Generation

A rising trend in the green technology world is experimentation with power generation not from biofuel, water, or even wind, but the movements of people in their everyday life. This is called kinetic energy generation, and you may have heard of it briefly in the past few years. For instance, there is a dance floor which harnesses the movements of those above it to generate electricity. In addition, Nokia recently introduced a phone that charges itself by generating power from the vibrations of their user’s movements. Such electricity generation techniques seem to hold the key to sustainable energy as fossil fuels become harder to come by and consumers are looking for green alternatives. Before making judgments, however, one must examine the whole technology and its implications.

First things first, how does this stuff work? In simple terms, a magnet bounces around with some copper springs to produce electricity. In more scientific terms, the kinetic energy generator works because of the Faraday principle. The movement of the magnet causes a movement of its magnetic field which moves electrons which are conducted by the copper wire into a battery. This is generally how these generators work, but as it is a relatively new and open field, producers of this technology are incredibly stingy with any real, solid, and thoroughly explained information.

What we do know about generating kinetic power, is that it’s all about long periods of repetitive, constant motion. For instance, a biker, jogger, or walker who wears one of these devices while exercising would create much greater amount of energy than a baseball player who wears the device during a game. The repeating movements for long time periods are more important than the strength of each motion.

Recently, the Department of Defense recognized the military possibilities of this technology for use in combat situations. Currently, soldiers lug twenty to thirty pound batteries in their rucksacks to power their communications tools. By adopting this kinetic energy generation techniques, soldiers could lose the heavy batteries and replace them with smaller ones that charge constantly as they move. This could increase mobility and energy reliability of troops. To ensure fast development of this technology, the DOD invested nearly $10 million their development.

Well, if kinetic energy generators work for soldiers, they will surely work for civilians in the US right? In most cases, the answer is no. Kinetic energy generators rely on the movement of the wearer to create electricity. Most sedentary Americans produce only energy to power a phone for 15 to 30 minutes. This means that the technology is far from applicable to do anything more than briefly extend phone life. The cost of this technology is also an issue. As there is no possibility for municipal or government use of the energy, it would come down to consumer action to popularize the product. Current models of kinetic energy producing products sell for between $150 and $300, making it easier and cheaper to simply charge devices at power outlets. The only thing a consumer really gains from this product is a superficial (and largely false) sense of helping the environment.

What about the kinetic dance floor? Surely this technology could produce enough energy to make a difference in energy usage. Each floor tile, about 30 inches square, produces about 35 watts of energy in ideal conditions. Now imagine, perhaps, a whole room in a busy New York City subway station, covered with these tiles on the floor. There are 5000 tiles total and they operate at peak production 24 hours a day. Together, these tiles could produce 4200 kWh (kilowatt hours) of electricity per day. This sounds like a lot of energy, however the average American uses 250 kWh of electricity per day. This means that the entire system would provide power for only 17 people if operating at maximum efficiency all the time (both of which are basically impossible to achieve).

So where do we go from here? Obviously, this technology only makes sense for the most active of people and would provide energy for only the occasional charging of an electronic device. The vast majority of Americans move too little and use too much electricity for this technology to be feasible. Without nearly magical improvements in efficiency, kinetic energy generators are and will stay unpractical. Green energy pursuers should abandon this area, as it is a nice theory, but an incredibly weak producer in practice.