We are currently in the midst of the world’s largest human migration. It takes place as a vast movement from rural areas to cities and is most pronounced in poor and rapidly developing parts of Africa and Asia. New cities spring up. Existing ones grow beyond recognition. Over the next 30 years we will be building a new urban habitat for about a third of the world’s population. The way we will build those cities will lock in certain lifestyles and emissions for decades to come. Therefore, we have to do it intelligently: in a way that is inexpensive, provides comfort and safety, saves local resources and keeps the climate impact low.
A game changer: industrial construction
A large piece of the solution can come from “house factories.” These factories industrially produce modular building blocs. The idea is simple. A factory churns out three dimensional modules (including complete kitchen or bathroom units). They are then transported to and assembled on site in a matter of days. Modules, based on lightweight construction, can be stacked up, up to four floors high without additional static structures. Buildings could even be as high as skyscrapers. For that, one would have to pre-construct a steel skeleton into which the modules can then be slotted. The idea of modularization is to provide a product that has standardized elements (thus bringing down cost), while offering a large degree of individualization (in the way these elements can be combined).
If you now picture a drab socialist building block, think again. The best architects could work on the buildings in the same way as some of our best designers work on our cars, which are also modular products, out of high-tech factories. As we speak, the first such modular housing factories are being built in Europe.
In a recent study, Wildemann and Grundke, outlined how industrialization and modularization of construction can reduce the cost of buildings by up to 76% (at constant building type and functionality). In addition, overall construction speed would be increased by 50%, and errors reduced by at least 90%. The entire process — from how a building is chosen and designed, to how it is manufactured, to how specific suppliers are integrated and finally how it is assembled on site — is optimized, digitalized and integrated. This is good for individual buildings. The real impact, however, will be felt when implemented at scale: in our future cities.
Our urban future
By the year 2050 there will be an additional 2.5 billion people living in cities — 90% of them in Asia and Africa (as compared to 2014). India alone will have around 440 million more urban residents. China follows with 292 million and Nigeria with 212 million (UN ESA 2014). The number of mega-cities — cities with more than 10 million people — will rise from 10 to 41. However, the fastest growth will be in mid-sized cities (up to 1 million inhabitants).
In order to keep pace with the rapid growth of the urban population, large-scale urban development is currently underway in across the globe. Some of it is planned, some is not. In either case, it can be dramatically challenging. Take India’s capital Delhi as an example.
The case of Delhi
The old city of Delhi (Shahjahanabad) had originally been built in the 17th century for a hundred thousand residents. In the early 20th century, the British added their imperial capital “New” Delhi to it. It was a stretch of bungalows, roundabouts and tree-lined avenues to house around 50,000 residents. From these quaint days, Delhi grew to a city of 25 million by 2016. Surrounding towns, like Gurgaon or Noida, are being swallowed up. Every day, a thousand migrants from India’s rural hinterlands arrive in the city. By 2050, the UN expects Delhi to be the world’s second largest city, with 36 million people.
Already today, Delhi is stretching well beyond its limits. Millions of inhabitants live life at the very edge of society, in slums, in vast shanty towns, or on the streets. Throughout the city, there are already acute water shortages. The air is among the most polluted anywhere, reaching levels way beyond the measurement scale of the World Health Organization. Traffic is highly congested. New infrastructure and housing construction projects take long to complete and execution quality is often poor.
Using modular construction to go green
How could an industrial construction process help? For one, it could make large numbers of houses available quickly and at low cost. However, at a more strategic level, it could help make the urban stock “smarter” and more resource efficient. Technologies to harvest water or save energy, to generate electricity or to connect with the city (grid, mobility) would be cheaper and could be much better designed and integrated. What is more: it might actually get done, at scale and speed.
Take solar as an example: integrating solar PV systems into the design and construction of houses in a factory process could reduce the cost of residential solar by at least 50%, according to TFE Consulting estimates. The solar system could be financed together with the house or they could be financed in an aggregated manner by a third party. The house can directly consume the generated power. Alternatively, it can be sold to the neighborhood through a microgrid, or fed into the overall power grid. A much higher share of residential solar could help reduce air pollution (by reducing diesel usage), increase the availability of electricity, avoid substantial grid losses, and even provide an additional source of income for the community living under the roof.
At the same time, building large settlements offers an ideal market opportunity for the industrial, modular construction method. They ensure the scale needed to reduce initial transaction costs. These include, for example, the costs of location specific designs and the resulting adjustment of the manufacturing process. In addition, a large project can be used to guarantee the best possible utilization of a factory (in order to make full use of the cost advantages).
Population, resource and climate pressures demand that we build better cities than we did in the past 50 years. However, currently, in many countries, the cities we build are actually worse. The construction industry often operates in a low-tech, localized and semi-informal manner. To deal with the challenges outlined before, we need to professionalize it. That means taking it from pre-modern methods into the industrial and then digital age.