Production planning of CHP plants integrated with bioethanol production and local renewables

Sammanfattning: Production planning of an energy system is dependent on parameters such as energy demand and energy conversion technologies, which are influential in making decisions on operation strategy and optimal performance of the system. In accordance with the European Union energy policy, the share of renewable resources in the energy supply is growing. Improvement in energy technology is considered to be a pathway to achieve the target of 100% renewable power supply in Sweden by 2040. Increased utilization of renewable resources in energy systems and transportation sectors as well as improved energy conversion technologies would add complexity to the systems. Development of such complex systems depends on several key parameters, including availability of local resources, changes in daily energy use behavior, market price and weather conditions. Therefore, optimization and long-term production planning of such systems will be crucial considering the alternating nature of renewable resources.  The aim of this thesis is to develop an optimization model for a regional energy system to provide advanced knowledge for production planning for combined heat and power (CHP) plants. The energy system in the county of Västmanland in central Sweden is used as the case for study. The regional system consists of CHP plants, heat only boilers and renewable resources. Two different optimization cases are developed for the analysis, one with increased energy supply from local renewables, and the other with integrated transport fuels production in a polygeneration system. The model includes the whole chain from availability of resources to the final energy use. The effect of different parameters relating to trends in energy demand and supply on operational strategy of the studied system is investigated by developing different scenarios. The potential solar power production from grid-connected solar cells installed on the rooftops of buildings in the region is added to the system in the base scenario. Then, the first scenario analyzes the increased application of heat pumps to replace the district heating in some of the buildings in the region. The influence of electrification of the transportation system as a result of increased penetration of electric vehicles is investigated in the second scenario. Two further scenarios evaluate the effects of integration of bioethanol production with existing CHP plants and increased application of bioethanol cars and hybrid vehicles in the regional transportation system. The study demonstrates the importance of production planning of the energy system at the regional scale in relation to resource availability and energy imports. The main conclusion of this thesis is that the polygeneration and increased use of heat pumps could influence the production planning of the system in terms of fuel use, plants operation, fossil-based emissions, and energy demand and import. However, increased use of hybrid vehicles represents the optimal case for the mentioned parameters.