Energy harvesting – Part 1 – 5 obstacles to widespread use

A few days back I wrote about the Fluxxlab design proposal to harvest energy from revolving doors. Managing to install standalone energy producing devices is a significant event, much like when the first solar panels hit the market in the past. Therefore, I have decided to write a two part series, the first part is about obstacles to widespread use, part 2 is for now a viable and necessary option.

Despite the initial enthusiasm, energy harvesting is an old idea that has stayed on paper and is only now gaining some momentum. Car braking systems that recuperate energy to charge batteries are only now starting to appear in mass production and represent a very obvious application. As concepts, designers and engineers will seek more new applications for buildings and transport, it is inevitable that they are going to run against some hefty problems that need to be solved. Here is a few:

1. Energy availability: Like in the revolving door’s case, the energy source is neither continuous, nor of the same intensity. In other words, some of the time -in some cases most of the time- it is not possible to produce any energy at all, and during the periods when harvesting is possible things are not rosy with a well determined input.
2. Energy conversion: Energy harvesting is useless if we do not convert the available kinetic or other form of energy to useful electric energy. The efficiency of this conversion has to be pretty high, especially when we have short bursts of production. Most systems only work well under certain conditions, for example when mechanical revolutions are constant, or when wave patterns are regular. In many cases, for example when harvesting kinetic energy from random vibrations, it is awfully difficult to convert this random pattern in regularly flowing energy. The same when we have kinetic energy in the form of rotations, in which case frequency control is a major issue.
3. Combination with mains supply: If the converted energy is to be used immediately for consumption as it is produced or sold to the electricity company it must exactly match the mains electricity frequency in order to not cause problems to any devices.
4. Energy storage: In the very likely scenario that we wish to store the produced energy, it is a tough problem. We all know the linitations and cost of batteries. To actually integrate a complete storage module of any type is a significant operation that increases project size and complexity.
5. Cost: The more hardware and installation work is required and the more we intervene with the conventional course of construction, the more we increase capital expenditure, that will in turn require longer ROI periods.

For all technical problems there is already some solutions. Where I anticipate adoption resistance is in the fact that few applications offer good enough conditions for effective energy harvesting. Unfortunately, we still think in monetary terms, even for projects that are trying to help the environment. However, even when we are determined to spend more to achieve our goal, we still like to have clean, easy and quick procedures.

If harvesting is to ever see wide adoption, regulations or industry standards must be accordingly adjusted to ease wide adoption. Even more importantly, harvesting unavoidably competes with continuous green energy production methods, so its viability at the moment is in no way guaranteed. This is going to be discussed in the 2nd and last part of this short series.

Link: ElectronRun – Harvesting energy from revolving doors