Environmentally friendly approaches to technology development are important because they ultimately impact the future of our planet and the quality of life for the generations that follow.
In this context, when it comes to the technologies related to energy, we look for cleaner sources of energy, we look for technologies that generate energy more efficiently from these sources, and finally we try to design equipment that operate efficiently without wasting energy.
The article below pertains to technology that does not fall neatly into any one of the categories noted above. It has to do with regenerating energy. It is about saving the energy that might have been wasted and reusing it in some way.
The principle used in the system described below is in some ways similar to that in hybrid cars. In an hybrid vehicle, a traction battery provides power to a motor that supplements the gasoline engine as needed to move the vehicle. This battery is recharged when there is either some braking action, or when the automobile its trying to increase speed and build up momentum on a down-slope. Essentially what is happening is that the energy that is generated from braking, instead of being wasted as heat, is converted to electric power. Kinetic energy generated on the downhills is also converted to electric power. There is no additional external source of power. We are basically saving energy in the battery when possible and then using that energy later when it makes sense.
In the system described below, the trains provide electric power in real time to the underground stations when they brake to come to a stop in the station. The numbers from the article are an indication of the tremendous amount of energy that is available from this process, and also an indication of the tremendous amount of energy we are wasting today. It would be great if this kind of a philosophy – of taking advantage of the unused energy from an inefficient process and reusing it for either the primary process itself, or for a secondary purpose – be considered more widely in the design of all systems that consume energy, especially since we have many technologies in place today that are still quite inefficient. Towards this end, the ability to store energy efficiently on a large scale at a reasonable cost point is still a significant technological issue to be addressed and solved.