Universiteit Leiden

nl en

Report: what does our urban mine have to offer?

On 21 January, the Institute of Environmental Sciences (CML) has released two reports on circular economy and urban mining in the Netherlands. In them, together with Statistics Netherlands, they take stock of part of the Dutch ‘urban mine’: how much raw material can we reuse from the electricity grid, or from existing buildings?

The CML reports are published on the day the PBL Netherlands Environmental Assessment Agency hands over the Integral Circular Economy Report (ICER) 2021 to State Secretary Stientje van Veldhoven. The CML reports are part of the ‘Monitoring en Sturing Circulaire Economie’ programme (see box), the research programme coordinated by PBL on which the ICER report is based. The CML is one of the institutes that contribute to this programme on a structural basis.

Ester van der Voet

The first report maps the stocks of materials in existing buildings – such as concrete, steel and wood – but also of electrical appliances and textiles. The second report takes a close look at the electricity system and examines the inflow (demand) and outflow (discard) of materials up to 2050, under various scenarios. The outflow reflects the amount of materials that will be available for reuse or recycling: the urban mine of the Netherlands. ‘Our report shows that the urban mine for copper in the Netherlands per capita is already larger than the amount of copper per world citizen that is still in geological mines,’ says CML researcher Ester van der Voet. 

Society as a mine

‘The idea behind a circular economy is that materials and resources are kept in use for as long as possible, so that the need for virgin raw materials will be as little as possible,’ she explains. ‘Urban mining is part of that: society is considered a mine from which materials can be extracted to be used again. A circular economy actually implies a shift from geological mines – such as an iron mine or a sand quarry – to urban mines.’

The copper mine Chuquicamata in Chili. The mine is one of the largest open-pit copper mines in the world. (© Diego Delso)

Black box

However, we don’t know anything about this urban mine, says Van der Voet. ‘There is a lot of information about production and consumption, or about the amount of raw materials we extract from geological mines. But we do not know where all those raw materials end up. As soon as they enter the use phase, the information dries up. The quantities of materials in buildings, infrastructure, vehicles and all kinds of in-use products are unknown, and are not recorded anywhere. Even for waste, the outflow from the urban mine, we often do not know its composition.’

And that knowledge is essential, argues Van der Voet. ‘The materials in urban mining are in use and are therefore not readily available. On the other hand, the urban mine is constantly being replenished, while geological mines are being depleted. A business plan for urban mining will therefore have to look different, but it is equally important to make it. Just look at copper, where the urban mine has a lot to offer.’

Energy transition

In 2019, the CML and Statistics Netherlands already mapped out the materials stored in the existing electricity network. This year, CML researchers report when those raw materials will be released for new projects and how many new materials will be needed. ‘The energy transition makes this sector extremely interesting,’ says Van der Voet. ‘There are more and more solar panels and wind turbines, and the energy grid needs to be expanded. This increases the need for materials. Think of more cables, metal for the wind turbines and so on.’

At the same time, the energy transition also frees up old materials. ‘The coal power plants will eventually be closed down and a lot of quality steel will be released from them, as well as old cables full of usable copper and aluminium. In addition, wind turbines and solar panels have a relatively short lifespan, so the first batch of old wind turbines is already decommissioned, delivering materials which we can reuse or recycle.’

The figures show the steel demand (inflow) and the discarded steel (outflow) of the electricity system in the Netherlands until 2050. The inflow appears to be greater than the outflow: the stock is growing. An important share is formed by wind turbines. The peaks in the outflow are coal power plants at the time of their planned decommissioning. This means that in the short term, new steel will remain necessary to build up the stock. In the longer term, after 2050 when capacity has been built up, demand may level off and outflows will have a chance to catch up with inflows. (© Institute of Environmental Sciences)

Recycling old buildings

In a second report, the CML, together with Statistics Netherlands, estimates the stock of materials in buildings. ‘This involves an awful lot of raw materials, mainly concrete,’ says Van der Voet. ‘We have mapped out the extent of this mine. Next year, we are going to see what can be reused. That ranges from parts – such as windows and doors – to entire facades. But materials such as steel and concrete can also be recycled.’ And those techniques already exist, says the environmental scientist. For example, the old high-rise of Leiden University's science Faculty has been sustainably demolished and reused.

This video can not be shown because you did not accept cookies.

You can leave our website to view this video.

Promotional film about the construction of Biopartner 5, which reuses 165,000 kilograms of waste steel from the demolished Gorlaeus Highrise.

‘The thing is, recycled concrete is more expensive than new concrete. In addition, construction companies hesitate to use these materials because they do not always trust their quality and whether recycled concrete meets all the strict guidelines. While the quality of recycled concrete can be just as high. So there is still room for improvement in the communication I think.’ 

Circular economy: fact or myth?

In contrast to earlier hypes in the area of sustainability, Van der Voet does see a future in the circular economy. ‘The principle is sound. The growth in the demand for raw materials will not go down in the foreseeable future, and waste flows will therefore continue to grow as well. We must therefore continue to develop recycling and urban mining and use our materials for longer.’ Van der Voet chooses to face the future with hope. ‘It is undoubtedly difficult to apply circularity in practice, but I believe in it. That is why in the coming years we will continue to investigate the urban mine in the Netherlands. Think of the transport infrastructure and gas pipelines. The gas pipelines are particularly interesting because of the objectives of de-gasifying the Netherlands: all these materials will then be available for re-use and recycling.’ 

Read the reports of CML here.

The Dutch circular economy

The reports of the Institute of Environmental Sciences are part of the ‘Werkprogramma Monitoring en Sturing Circulaire Economie’ 2019-2023, a partnership of Statistics Netherlands (CBS), the CML, the CPB Netherlands Bureau for Economic Policy Analysis, the National Institute for Public Health and the Environment (RIVM), RVO.nl, Rijkswaterstaat, TNO and Utrecht University (UU), led by the PBL Netherlands Environmental Assessment Agency. The Dutch government is striving for a fully circular economy in 2050. The work programme aims to enable monitoring and evaluating the course set by the Cabinet towards 2050, and to advise the government on it.

Text: Bryce Benda

This website uses cookies.  More information.