Raising energy efficiency by an order is crucial when it comes to even getting close to slowing down man-made climate change, let alone stopping it. At the same time heatinvolving industrial processes are a pillar of modern society as is food production and both are not just supporting an ever-growing world population but are at the same time also expected to grow exponentially. This thesis will highlight possibilities to use low temperature waste heat and at the same time combine the efficiency-measure with a sustainable food-production-project that can be situated in the midst of its customers, instead of being in a far away rural area. Joining these two together as smoothly as possible, an overall increase of efficiency shall be demonstrated that does not sacrifice the need calculate economically in the long run. Carefully assessing the approach and planning the systems integration provides the basis for a showcase scenario: Saving energy from going to waste while simultaneously producing highly valuable fish-protein in an utmost sustainable way when it comes to energy-consumption, water-consumption, distance to the customer and of course an ecologically certified breeding-environment that does after all (also) put the well-being of the useful animal on top of the list. An all-rounder that will as well help directly to mitigate climate change and overfishing just like excessive transportrelated emissions, the overwhelming trade balance deficit when it comes to fish-imports, and even create local jobs. Stopping greenhouse gas emissions in a paradigm of constant and exponential growth needs nothing less than solving problems 'Seven at one blow'. For practical use, several calculations and assessments both of technical and economic nature are provided and backed up with real figures. As far as technological assumptions are concerned, the numbers may very well keep their value for a good amount of time, while the economic figures might on the other hand be out-of-date rather soon: Quickly changing subsidy regimes or market prices of both energy in its various forms and the produced fish as well as the feedstock, may vary strongly over time. To compensate for that, the emphasis is rather to put the technical options and the 'bigger picture' under the assumption that in the long run prices for fossil energy carriers and food will rather climb along with the intense need to mitigate climate change.