Difficulties in green design

There was much self-congratulation in Paris in mid-December at the close of COP21 – the Climate Change Conference. Everyone seemed happy that ‘we are serious about this now’ before returning to throw Yule logs on their home fires. But, who is actually going to do what as a consequence of this agreement remains to be seen. It struck me as a destination without detailing the journey – the nub of the matter is that we must burn less fossil fuels. So, is that all?

Away from the energy supply sector, can design engineers have any impact on climate change? It is not as straightforward as it sounds. Obviously an electromechanical product can be efficient and therefore use less fuel, but what do you make the product out of? For example, the environmentally conscious engineer might choose to design a product out of recyclable materials like aluminium and steel - the British Metals Recycling Association calculate that around 60 to 80% savings can be made in recycling metals compared to making them from ores. But when it comes down to it, the flood of cheap steel from China is likely to mean it will be made from ore there, which is then shipped halfway around the globe.

It may be cheaper, but in terms of emissions it is far from ideal. Or perhaps you may be tempted to improve the efficiency of a moving object by lightweighting, perhaps using composites. Environmentally sound in use, but only a limited amount of it can be made from recyclable material. In these sorts of cases the life-span of the product, and the energy saved during it, can be balanced against the emissions created during its manufacture. A more energy efficient product is more environmentally friendly.

It almost seems as if the environmental agenda can be split into emissions reduction and waste reduction – and often these two, without clever engineering design and insightful supply chain management, can be pulling in opposite directions.