Smart homes are just a stepping stone on the road to smart cities. Bottrop, a small town in Germany, has been given a new lease of life and is now well on the way to its rebirth. An official decision was made to convert Bottrop from a former mining site into a green city of the future.

Not so long ago, Bottrop was a rank-and-file industrial town in the Ruhr, and lucky enough to be located near critical highways and railways. The local mine, refinery and several industrial plants provided the majority of jobs for the locals and created a strong foundation for the town to grow. In more recent times, mining in Bottrop slowed down, and with these production cuts came staff reductions. Bottrop was looking at a future of stagnation at best. The crisis also hit the local Polish population of migrant workers from Silesia, including those from Gliwice, the partner city of Bottrop. Over the decades of living and working at the Bottrop mine, the these Poles had put down roots, and even formed their own football team, FC Polonia Bottrop e.V. However, like other citizens of Bottrop, these Poles have become the beneficiaries of a large-scale project designed to convert Bottrop into a city of innovation. Now Bottrop is 'a thing' not only in the Ruhr, but all across Germany. Soon the whole of Europe will be learning more about the outcomes of this technological and psychological revolution under way in Bottrop, a huge Petri dish in a unique experiment into the urban fabric.


Smart City

The goal of Bottrop city officials is clear, but extremely challenging. While the European Union has mandated a 50% reduction in CO2 emission levels by 2050, Bottrop wants to achieve this by 2022. The success seems to be drawing closer - they have already managed to shave 38% off its carbon footprint. This would not be possible without a large-scale approach, so how was it done? The whole of Bottrop became unconditionally committed to this goal, with no exceptions granted. Entire residential housing estates and public buildings are gradually being refurbished, including thermal efficiency improvements and the installations of solar panels, which are popping up all over the place.

These energy-saving and renewable energy sources are intended to change the old, smoky Bottrop. The local motto is now “Blue Sky – Green City”. No more pollution, no more post-industrial wasteland, and no more high operating costs for old houses. Bottrop is going green, cost-efficient and state of the art. To meet these lofty objectives, just one part of the overall goal of the project, five areas of action have been established: Housing, Occupation, Energy, Mobility, and City. Although smart, the plans would most likely fail if not for the tenacity of the Bottrop city officials, a huge commitment to promotion, the support of 70 partnering businesses, and the aid of 14 R&D centres, which have been providing technical assistance and know-how for the project frontlines.

The Bottrop conversion project is financed with public funding and many private contributions. The project consortium that initiated this conversion of Bottrop into a smart and green city hopes that, when the project is complete, tested and proven true, it will be adapted by other cities and towns in Germany and across Europe.


Initiatives of the town and its residents

1963 was a milestone year for Bottrop. This was when the local industrial boom began, with a huge extension of the production capacities. Large multi-family residential estates were built and teemed with the employees and their families. These buildings today occupy three quarter of the developed urban areas of Bottrop and are now beginning to enjoy their second youth. The scale of their thermal upgrading is huge. The outer walls are lined with thermal insulation, old windows are replaced with modern, energy-saving counterparts, while the legacy plumbing is stripped out to make room for much more advanced systems, often with heat pumps for underfloor heating. Photovoltaic panels lining whole walls and roofs are not an uncommon sight in Bottrop. A PV system installed on a single block of flats can provide up to 22,000 kW of power per annum. Given that the energy demand of a thermally retrofitted, average-sized apartment block in Bottrop is about 19000 kW/a, the residents can enjoy a surplus of 3000 kW. The micronetwork of energy cooperatives established in the town for the transmission and storage of energy enables the citizens to share or resell this surplus power.

Hence, the consumers of Bottrop have stepped up to become prosuments. Not only do they use power, they also make it. One of the targets of the Bottrop conversion project is to build 10 combined heat and power stations on a Home Power level, and 100 micro power plants in local, residential estate-level grids. The plans for Bottrop include the conversion of household waste biomass into energy and the construction of 'green' sewage treatment plants. Many buildings have now been retrofitted with smart management systems to monitor the plumbing. The smart management systems analyse and keep energy consumption below certain limits.Thermal efficiency improvements and RES project development is not all Bottrop has been doing. A total of 200 subprojects have been launched with the commitment of the local community to make the urban scape friendly to the climate. The citizens of Bottrop can review, improve and propose their own solutions to these subprojects.


A polyurethane-insulated city

Many buildings that have thermal retrofits feature insulation made from modified polyurethane, or PIR (rigid polyisocyanurate). This material reduces heat losses through the walls, roofs, floors and foundations. This means that not just roofs but whole buildings may be thermally retrofitted, from the ground up. The Covestro building in the downtown district of Bottrop is one such example. Polyurethane insulation panels were installed on the walls and roof to improve the overall energy efficiency. The reason that the designers chose polyurethane was due to its superior thermal insulating performance, with a low thermal conductivity value λ of 0,024 W/mK. Aside from the next-generation space-age products like aerogel, no thermal insulator is a match for PIR foam when it comes to the thermal retrofitting of roofs and whole buildings. 

Did you know that?

Bottrop has the longest indoor ski slope in the world. The 640 m skiing route at Alpincenter Bottrop houses runs for beginner and advanced level skiers. With a downgrade of 24 percent, it is very attractive to skiing enthusiasts, and there is even a jump run for freestylers, ski and board rental, and training by professional skiing instructors. Those who would rather seek thrills away from the snow can enjoy the nearby rope course, the summer toboggan circuit, or even a game of paintball. Alpincenter Bottrop offers its own unique attractions: indoor skydiving in Germany's only vertical wind tunnel.