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By Kim Brinck & Susanne Wellington Hansen Again and again we hear the message that resources are scarce, and that we have to ensure that they are not lost in our waste. Explanations as to which resources we are talking about and how we avoid wasting them, however, are in short supply. Waste may contain many different resources depending on origin and prior use. The resources of waste may be considered a material resource, an energy resource or a nutrient resource, and typically a waste fraction will comprise a mixture of these in varying quantities. When evaluated from a materials and nutrients point of view, however, many waste fractions do not contain any significant recyclable resources without them first being subjected to thorough sorting and cleaning processes - processes which both economically and in terms of energy are very costly. At modern waste to energy facilities with combined heat and power production a highly efficient recovery of the most important resource of these waste fractions - energy - can be ensured. When material resources are recycled, an actual environmental benefit only occurs if it results in savings of virgin materials. Similarly, for it to be an environmental benefit, the recovery of energy has to supplant other energy production whereby the consumption of fuels and/or materials is spared. Despite global efforts to reduce our reliance on fossil fuels by developing alternative renewable energy production, the production of both power and district heating, will in the coming 20 years continue to be broadly based on the use of fossil fuels. This is why the utilisation of the energy resource present in waste both saves the consumption of fossil fuels and the emission of greenhouse gases (GHGs). Even though many European countries are planning a conversion of their energy production from being fossil fuel based to being biofuel based, energy recovery from waste will continue to be an environmental benefit as it will save bio resources, w