1 Introduction The provision of clean, affordable, and reliable energy represents one of the greatest challenges of sustainable development. From a spatial-planning perspective, it is inter- esting that more than half of the energy consumption in the developed world is related to the distribution of land uses (Owens, 1990). Energy-conscious design criteria have been articulated for the physical environment (see, for example, Edwards, 1999; Elkin et al, 1991; Frey, 1999). In practice, however, application is often limited to building scale (Williams, 2007) and neighborhood scale (Witberg and Zinger, 1999). A number of municipalities, such as Kalundborg and SamsÖ (both in Denmark), and Gu«ssing (Austria), have practiced energy-conscious planning and design at larger scales. Yet, it appears that projects focus on either urban or rural environments missing some of the potential benefits when these two complementary realms merge at the regional scale. Knowledge gaps exist in energy-conscious spatial planning and design, in particular at the regional scale. Existing knowledge on energy flow in natural ecosystems has not yet been explored fully in spatial planning and design. Natural ecosystems are described with the help of so-called ecological concepts, some of which reveal how energy flow is optimised in nature. We identify and discuss ecological concepts and strategies with respect to energy-conscious spatial planning and design at the regional scale. The hypothesis is that ecological concepts and strategies can inform energy-conscious spatial planning and design and thus support the development of a sustainable physical environment. 2 Present state of affairs The integration of system thinking into energy-conscious planning and design has proved to be successful. Energy-efficient dwellings and office buildings have been constructed, such as the ING Bank in Amsterdam and the WWF headquarters in Zeist (both in the Netherlands). A number of synergetic industrial networks such as at Kalundborg indicate the potential benefits of scaling up and pursuing system innova- tion on a bigger scale. Energy-conscious (and material-conscious) design principles have Ecological concepts and strategies with relevance to energy-conscious spatial planning and design Sven Stremke, Jusuck Koh Landscape Architecture Chairgroup, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands; e-mail: sven.stremke@wur.nl, jusuck.koh@wur.nl Received 30 June 2008; in revised form 12 May 2009; published online 25 March 2010 Environment and Planning B: Planning and Design 2010, volume 37, pages 518 ^ 532 Abstract. Sustainable systems utilise renewable energy sources and recycle materials effectively. In theory, solar radiation provides abundant energy to sustain humanity. Our capacity to utilise available sources, however, is limited and competition for resources is expected to increase in the future. Spatial organisation and design of the physical environment influences two aspects of sustainable energy transition: assimilation of renewables and energy consumption. How can spatial planning and design support the transition from fossil fuels to a sustainable energy regime? Natural ecosystems constitute one source of inspiration. They are described with the help of ecological concepts; some of which reveal how energy flow is optimised in nature. Ecological concepts and ecosystem strategies are not limited to the description of natural phenomena; they can also inform energy-conscious planning and design of neighborhoods, cities, and entire regions. We identify and discuss nine ecological concepts with relevance to energy-conscious spatial planning and design. doi:10.1068/b35076