Sustainability is what philosophers call an essentially contested concept. We can’t even all agree about what it means, though it seems that we can generally agree that it means favouring our political viewpoint.

To deep greens around the world, sustainability necessarily involves the destruction of capitalism, and anything short of that is quite possibly worse than useless. To German trades unionists it necessarily involves more union involvement in business decisions. To British Conservatives it might involve clean streets, NIMBYism, and trusting the market to save the planet.

But what does it mean to us as engineers? Though capitalism is not a necessary precondition for engineering, it is the model most of us know, and a project plan whose first stage was the overthrow of capitalism might be expected to be subject to delay. We are as engineers (rather than voters) indifferent to unionisation and its opposite, clean streets and their opposite, but NIMBYism is more of a problem.

Chemical Engineers design the very things which NIMBYists most don’t want in their back yards. It doesn’t matter how much effort we put into blending our designs into the background, or lessening their measurable environment impact. Rational arguments have no more effect on right wing NIMBYists than they do on the dreadlocked crusties who join them on protests against wind turbines, fracking and so on.

So we may as well let the politicians address the concerns of those who cannot be convinced by the science, reason and mathematics which engineers deal in. How can we as engineers address the rational, reasonable concerns for people and the wider environment, which remain even after we have stripped away the self-interested rhetoric of the (usually ill-informed) campaigners?

The Institution of Chemical Engineers have helpfully drawn up sustainability metrics to assist with this. They do not require the destruction of capitalism or the abandonment of personal hygiene (did you hear about the new shampoos for crusties? It’s called “go and wash”). Neither do they require us to blindly trust that markets will take into consideration environmental or societal costs (just like they didn’t in Europe before regulation make caring about such things mandatory, and just like they still don’t in less regulated countries)

The engineer’s approach implicit in the metrics is to carry out a cost/benefit calculation. They require us to measure our use of environmentally important resources and generation of waste per unit of produced material but to balance this against economic and societal goods such as wages and investments, research and development, workplace training and education, stakeholder involvement and so on.

This is the correct approach for an engineer. It avoids two approaches which are incompatible with engineering rationality. Both essentially set the value of environmental goods to infinity, and the value of money to zero. You don’t have to be a capitalist to think this a questionable set of axioms.

The first of these two approaches is the strong version of the precautionary principle, used by political campaigners whose real aim is the destruction of capitalism. The precautionary principle places the onus on those proposing something to prove it non-damaging if there is no scientific consensus that this is the case. This principle has become a basic principle of EU law, not just in the environmental area where it originated. Tempered with practicality, and an understanding of what scientific consensus means, this is a cautious but workable basis for development. In the hands of zealots, it can be a way to prevent any development anywhere ever again. This approach is simply incompatible with engineering logic, though it can be found in the curricula of some engineering schools.

Of greatest concern to engineers are the approaches to design being taught throughout academia advocating maximum resource recovery (rather than maximum economically viable recovery), based on pinch analysis, and the so called “green engineering” based on a strong version of the precautionary principle.  If you aren’t costing you aren’t engineering. Process plant will never be free, and environmental resources will never have infinite value. “Green engineering” is neither green nor is it engineering.

Read more posts from Sean Moran, The Voice of Chemical Engineering

About the author

Professor Moran is a Chartered Chemical Engineer with over twenty years’ experience in process design, commissioning and troubleshooting and is regarded as the ‘voice of chemical engineering’. He started his career with international process engineering contractors and worked worldwide on water treatment projects before setting up his own consultancy in 1996, specializing in process and hydraulic design, commissioning and troubleshooting of industrial effluent and water treatment plants.

Whilst Associate Professor at the University of Nottingham, he co-ordinated the design teaching program for chemical engineering students. Professor Moran’s university work focused on increasing industrial relevance in teaching, with a particular emphasis on process design, safety and employability.

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