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Recycling of Waste Electronic and Electrical Equipment (WEEE) © ClimateTechWiki and respective owners

According to the EC (19 November, 2008) “waste means any substance or object which the holder discards or intends or is required to discard.” Recycling materials and products – that are considered waste - is an ancient practice which shows that in times of resource scarcity (i.e. shortage of virgin materials) societies attach more economic and societal value to their own waste. This implies that throughout time the definition of waste can change as well. Generally speaking longer use or re-use of materials and products this is often mainly to cover a society’s needs.

Regenerative braking in trains Electrostar c2c train using regenerative breaking in London (source: Bombardier)

Employing regenerative braking in trains can lead to substantial CO2 emission reductions, especially when applied to full stop service commuter trains (8 – 17%) and to very dense suburban network trains (~ 30%). Regenerative braking applied to freight trains can also lead to CO2 emission reductions, albeit considerably lower than for full stop service trains (~5%). When regenerative braking is employed, the current in the electric motors is reversed, slowing down the train.

Run of River Hydro for Large Scale Electricity Supply run of river image

Run-of-river hydro projects use the natural downward flow of rivers and micro turbine generators to capture the kinetic energy carried by water. Typically water is taken from the river at a high point and diverted to a channel, pipeline, or pressurised pipeline (or penstock). The technology is applied best where there is a considerably fast moving river with steady seasonal water. How much electrical energy can be generated by a hydroelectric turbine depends on the flow/quantity of water, and the height from which it has fallen (the head).