One of my pet subjects is making products greener (don’t forget about my free workshops at Dott this month), and the key question is “What makes a product green?”.

The short answer is one that, across its life cycle:

1. Uses less stuff

and/or

2. Uses ‘better’ stuff

“Stuff” is a highly technical term covering materials, water and energy.

“Less stuff” appears straightforward, but can be compromised by the rebound effect. Techniques include lightweighting, reducing friction, reducing leaks, reducing electrical resistance and miniaturisation.

“Better stuff” is harder to conceptualise, but materials should be non-toxic and of low embodied energy (eg recycled or natural), energy should be from renewable sources. The main problem with this approach is finding a sustainable supply of material, water or energy, for example the biodiesel/rainforest controversy.

Of course there’s a bit more to it than this, but these two principles underpin all the more complicated techniques and technologies.