Decentralisation: a fad or a necessary step towards a sustainable city? This question was at the core of the mini-symposium on ‘Decentralised Water and Energy Solutions’ on 15 October. The symposium was held at the conclusion of the TKI Closed-Loop Cleantech Playground project, which focused on the watercycle at De Ceuvel in Amsterdam North. Within the TKI Water Technology programme, KWR and its partners worked on the development of technology for De Ceuvel. The symposium’s goal was to share the experiences from various initiatives and to learn from each other.
Fifteen houseboats will remain moored for ten years at the former De Ceuvel shipyard and used as office spaces by a group creative initiators. Because of the temporary character of the project and the extremely polluted soil, no underground structures have been installed. The boats have no gas connections or sewer system. Instead, each one has a heat pump, solar panels, a dry-compost toilet and a helophyte filter. At the centre of the Cleantech Playgroun there is a composting installation, a struvite reactor and a greenhouse, where vegetables are grown using the compost and struvite.
No simple answer was found to the question: Decentralisation: a fad or a necessary step towards a sustainable city? It all depends on the specific case, the definition of sustainability, the governing parameters and the project’s delineation. Experience was garnered from a number of initiatives. Among other things, the 80 participants concluded that:
- Implementing local, small-scale solutions calls for daring and persistence, especially since solutions are unusual and not well known. A tension exists between restrictive rules and guidelines and the drive to bring about sustainability.
- Combining existing infrastructure with new, innovative systems (often from bottom-up initiatives) is a key challenge. A balance must always be struck between flexibility and economies of scale.
- Strict regulations apply to (decentralised) drinking water production. There must be a guarantee that drinking water is clean and sustainably produced at an acceptable cost. The room for experimentation is very limited: safety and public health are always paramount.
- Not all ambitious initiatives for decentralised wastewater treatment are realised. The treatment of (grey) wastewater – e.g., using helophyte filters – is however regularly applied with success.
- Water is not electricity, and the decentralisation of water provision cannot be modelled directly on the decentralisation of energy provision. The use of ‘smart’ facilitative systems, which involve little extra effort on the part of the user, is important for public acceptance and a smooth larger-scale implementation.
- The further development of customised sustainable and cost-effective water and energy solutions demands a multidisciplinary response to the opportunities that arise, together with a clear point on the horizon (vision) and applied (pilot) research leading to real (show) cases.