Existing approaches to reducing environmental impacts along the metal production and consumption chain are focused largely at the plant scale for primary production, rather than considering the whole metal cycle. As such, many opportunities for systemic improvements are overlooked. This paper develops an approach to designing preferred futures for entire metal cycles that deliver reduced carbon footprints. Dynamic material flow models in Visual Basic® are used to provide life-cycle-impact-assessment indicators, which help identify key intervention points along the metal cycle. This analysis also identifies which actors or agents along the value chain are responsible for, or can influence, behaviour which affects environmental performance. With this information, it is possible to evaluate different scenarios for transition paths to achieve reduced impact. These scenarios consider combinations of new technology, increased metal recycling and demand management strategies. A case study for the copper cycle in the USA shows that to meet a CO2 reduction target of 60% by 2050, innovative technologies for primary processing of mined ore will play a limited role, due to their increasing impacts in the future associated with mining ever lower ore grades. To compensate for this whilst meeting demand projections, recycling of old scrap would be required to increase from 18% to 80%, requiring extensive collaboration between primary and secondary producers. An alternate scenario which focuses on demand reduction for copper by 1% per year, meets the CO2 target whilst only requiring an increase in the recycling rate from 18% to 36%. Together, these suggest that there is merit in examining the 'metal-in-use' stage of the metal value chain more closely in order to achieve targeted reductions in CO2. The approach also highlights the inherent trade-offs between different aspects of environmental performance which are required when pursuing CO2 reduction targets.
Colin Bennett on 04 Aug 15"Centuries ago, Nikola Tesla envisioned and pioneered the concept of wirelessly transmitting power over long distances through the Earth's ionosphere. In the recent past, wireless energy transfer has occurred by way of an electromagnetic (EM) field set to a certain frequency level. While transmission efficiency over longer distances is attained to an extent by this method, it becomes increasingly difficult when complicated pointing and tracking mechanisms are mandatory to maintain the right wavelength between the transmitter and the receiver. Another drawback to this approach is that any object that falls between the transmitter and the receiver impedes the beam, thus interrupting power transmission to a potentially harmful degree if the power level goes beyond a certain threshold point. Even though microwave frequencies could prove effective to transmit power over long distances through a radiated EM field, the aforementioned caveats still apply. The other possible way to wirelessly transmit power is by non-radiative fields. For instance, a transformer operates by magnetic induction drawing similarities to wireless power transfer. Energy transfer in a transformer happens from the primary coil to a secondary coil in the absence of a direct electrical connection. The same approach can be seen in inductive chargers found in electric toothbrushes, for example. However, for this functionality to operate smoothly, primary and secondary coils must be positioned in close proximity to one another."
