Resurseffektiv livsmedelsproduktion : Tillämpning av industriell symbios för ökad resurseffektivitet inom den svenska tomatodlingsbranschen

Sammanfattning: Industries with energy costs as a large proportion of their total costs are greatly affected by the instruments deployed to cope with the Swedish climate and energy policy goals. With energy costs representing more than 30 % of the total costs, tomato cultivators are one of the affected industries. In order to remain competitive with other countries, a more resource- and cost-efficient cultivation of tomatoes in greenhouses is desirable in Sweden. Based on the concept of industrial symbiosis, this study investigates the prerequisites for a resource-efficient production of locally grown tomatoes in Sweden through the utilization of low grade industrial waste heat. The study is based on the foundry industry as the supplier of waste heat. To investigate the environmental, technical and economic potential of the exchange of waste heat, a comparative life cycle assessment, an inventory of the supply of industrial waste heat in Sweden, a compilation of potential technologies for the recovery of low grade industrial waste heat for heating greenhouses and a comparative life-cycle cost calculation were carried out. To investigate the possibility of realizing the potential, an interview study with the aim to identify key barriers, drivers and success factors for waste heat recovery as well as design options for the waste heat agreement was conducted. A design proposal for waste heat agreements between the operators were developed to show how some of the identified barriers can be overcome. The result shows that there is a great potential to reduce the carbon footprint from the production of tomatoes by utilizing waste heat. The result also shows that the amount of industrial waste heat in Sweden would be more than enough to make the country self-sufficient in tomato production. Today, there are no developed technologies for utilizing low grade waste heat for heating greenhouses. Using conventional techniques entail excessive costs due to the low temperatures. This is particularly true when the heat flow is not continuous. Therefore, technological development is necessary to increase the potential of the concept. The interview study indicates that the main barriers to realizing an exchange of waste heat are lack of knowledge regarding the available amount of waste heat, lack of continuous flows of waste heat and uncertainty regarding the design of an agreement for purchase/sales of waste heat. The main drivers are economic, but concern for future legislation on waste heat and social driving forces, such as creation of new job opportunities and a prosperous countryside, are also important. The success factors of greatest importance are the ability of both parties to benefit from the exchange, a mutual quest for both parties to be successful with their businesses and that there are other forces than economic ones to initiate collaboration on an exchange of waste heat. The majority of the identified barriers to waste heat exchange are associated with the collaboration between different parties. Therefore, it is important that these barriers are overcome by designing a waste heat agreement that is beneficial to both parties. The parts of the agreement that are crucial are the term of agreement, security of supply, allocation of costs and the price setting of the heat. Overall, it can be said that there is a great potential for the waste heat concept, but many barriers and questions remain before realization is possible. This study has contributed with knowledge about the current situation regarding the potential to realize a waste heat exchange between an industry and a greenhouse. The study provides insight into what remains to be established before the commercialization of the concept is possible.