Peter Luscuere, Delft University of Technology

The world-population has been growing from the beginning of mankind to 1 billion (1804), at the start of the Industrial revolution. To reach the 2nd billion (1927) it took 123 years, the 3rd 33 years (1960), the 4th 14 years (1974), the 5th 13 years (1987), the 6th and 7th (2011) each 12 years [1]. Not only the number of persons living on this world has exploded since the Industrial Revolution, so did their consumption. As of the 1st billion marker until today, the energy consumption per capita has more or less quadrupled to the current 72 GigaJoule per person, leading to a combined 25-fold increase of our energy consumption over a period of 200 years, all powered by depleting fossil fuels.

Comparable pressure can be felt on other natural resources, such as water, materials and topsoil needed for food production. All of these resources are consumed: fossil fuels are burnt leading to Climate Change, water is contaminated to the point it can no longer be used, top soil being lost by 50% over the last 150 years [2] and materials are consumed to the point of depletion [3]. This is a linear process at work: Take, Make and Waste, as Michael Braungart is calling it in his book on Cradle to Cradle®. And such a linear economy does not run forever on a finite planet [4]. This is the basic fact why circularity is needed. We need to be able to replenish our resources over and over again. Energy, water, materials or topsoil: they all have to be renewable.

For energy the solution is obvious: the sun provides us with 5-10,000 times more renewable energy than we need. In Germany the equivalent of 40 Nuclear reactors is installed by placing PV-systems, predominantly by individual investors, in just the last 10 years. In the area of water cleaning great steps are made using decentralized cleaning techniques at places where the concentrations of contaminants are high, like hospitals, and biological cleaning systems in buildings. Urban Green can contribute to topsoil production, and large scale rehabilitation of disturbed ecosystems is successfully deployed. But the question is whether this is enough. Biological materials are renewable by definition: they grow. But efficiencies can be increased dramatically by choosing different crops and harvesting techniques. The technical materials, finally, are more troublesome. Some of those materials are at the depletion point of economical reserves. An immediate consequence will be: steadily increasing prices with alternating fluctuations. The only way to cover this is by better recycling and, upcycling techniques. And all this by taking account of health effects as well as social consequences.

Here is where new business is sprouting; design and development of new materials and products that can be separated into their initial constituents, with new processes enabling this renewability and as a consequence new ownership and business models. Circularity is just a means to reach the real objective: renewability, be it for energy, water, materials or topsoil.

That is also the central theme of the Symposium ‘Circularity in the Built Environment’ on July 1st at Delft University of Technology.

[1] Worldometers:

[2] WWF:

[3] USGS:

[4] Story of Stuff:

TU Delft