Universiteit Leiden

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A smarter approach to energy and raw materials

Over the past century, the world population has grown exponentially, as has our need for energy and raw materials. If we wish to continue to live prosperously in the future, we have to radically restructure our economy and consumption. Scientific research shows us how to do this.

‘When you hear “sustainable use of raw materials”, many people think of recycling,’ says Arnold Tukker, Professor of Industrial Ecology. ‘But we need something much more radical. We have to completely rethink our approach to supply and demand, production and consumption, stocks and waste.’ He mentions a few examples: ‘Make materials less complex. Make sure that components can be reused. Create a society built on “elements of hope” - materials such as sand, iron and aluminium that are so common that scarcity is not likely to be a problem any time soon.’

Tukker is Scientific Director of the Leiden Institute of Environmental Sciences (CML) as well as Director of the Leiden-Delft-Erasmus Centre for Sustainability, a partnership across three universities and different academic disciplines. From chemists to engineers and computer scientists, from psychologists to economists and public administration experts: all perspectives are represented. ‘They have to be, because we are facing a massive challenge.’

Each of the universities has its strong points, explains Tukker. ‘Delft is good in new technologies and design,’ he says. ‘Rotterdam in business and policy. And we in Leiden investigate the ‘metabolism of society’: how do physical flows of raw materials move across the world? How important are they? What are they influenced by?’

Raw material flows

Leiden maintains the world’s largest database in the field of raw material flows, including gas and coal. ‘The database covers the entire economy of the 44 largest countries,’ says Tukker, ‘and the import and production of 180 product groups over the past fifteen years, including emission and waste streams.’

René Kleijn, senior university lecturer and Scientific Director of the Industrial Ecology department, also works on the raw materials database. ‘We use it for large-scale analysis projects,’ he explains. ‘For example on aquaculture, recycling of concrete and other construction materials, and materials needed to produce sustainable energy.’

The current generation of windmills, for example, still contains materials that are finite. The demand for clean energy means that already we have to increase the production of raw materials such as copper in order to meet the demand in fifteen years’ time. The challenge is to look ahead, says Kleijn. ‘You can also make windmills without scarce metals – they may be slightly less efficient, but a more future-proof source of energy. You can only make these kinds of considerations if you have a clear view of the material flows, which is precisely what our database provides.’

One of the consequences of upscaling wind energy is that the earth metal neodymium, which is used in the wind turbine generators, is becoming scarcer.

Circular economy

A frequently heard concept in this context is the ‘circular economy’: an economy where energy and materials are constantly reused, and there’s no waste. ‘The economy is not likely to become fully circular any time soon,’ says Kleijn. ‘There will always be raw materials that are too expensive, too energy-consuming or too polluting to recycle. In these cases you shouldn’t do it– recycling should never be a goal in and of itself.’

But we still have large supplies of raw materials in unexpected places. As an example, Tukker mentions the PUMA project: Prospecting the Urban Mine in Amsterdam, being carried out by CML researchers. This project maps precisely where metals, such as steel and copper, can be found in Amsterdam. ‘For example in ships and in buildings. The next step is to design an infrastructure to exploit this “mine”.’

Leiden is also strong in so-called life cycle analysis, or LCA: a method to map the origin and destination of raw materials, including the energy required. The best-knwn example is: Is it better to wash your coffee cup or use a plastic disposable cup? ‘The answer is: it depends,’ laughs Tukker. ‘What we do is map the factors this depends on for the most important product groups.’

In a city like Amsterdam there are a lot of reusable materials. The PUMA project aims to exploit this ‘urban mine’.

Leiden-Delft-Erasmus Centre for Sustainability
PUMA research project

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