Feasibility study of a district heating system in the Spanish city of Gijón

Abstract: The current energy context is characterized by the absolute necessity to reduce carbon emissions in order to tackle climate change and avoid its bleakest consequences. Furthermore, the overall energy supply system presents plentiful inefficiencies that lead to outrageous waste of energy.                 Spain's energy outlook is also marked by its astonishingly high energy dependence, which has contributed to its secular deficit in the trade balance.                 District heating systems permit to cover the heat demand from the residential, service and some components of the industrial sector utilizing excess heat that otherwise would be wasted, thus, reducing the total primary energy demand. In addition, they ease the development of renewables and enable a a reduction of greenhouse emissions and other hazardous gases.                 Despite its their advantages towards the fulfilment of climate change goals and the improvement of the country's economic situation,  they they only represent an insignificant contribution to Spain's heat demand. The main target of this dissertation has been to determine the economic feasibility of regarding the development of a district heating system in the Spanish city of Gijón.                 The city of Gijón counts on several parameters that allow the development of a centralized supply, such as several sources of excess heat and a high population density with little urban sprawl. However, other circumstances such as the low specific heat demands endanger the success of these systems.                 The first step towards the determination of the economic feasibility has been to assess the heat demands of the different subsectors that comprise the building stock. Particular care has been taken in order to attain the most realistic figures to supplement lack of official statistics with other sources. Furthermore, the final results have been compared to other independent evaluations, allowing to determine its accuracy.                 Following the calculation of heat demands, the attention is focussed on the estimation of the costs of the different elements that entail the construction and operation of a district heating system; the construction and maintenance of the distribution network, the heat supply, and the interface between the distribution network and the customer's systems, the substations. The assessment of these expenses has endeavoured to be rather conservative.                 The estimation of the specific cost of heat for the district heating system and its contrast with current forms of heat supply has allowed drawing the conclusion that the new network would be economically competitive despite the conservative assumptions taken. In addition, the system would practically eliminate the emissions of carbon dioxide and nitrogen oxides from the building stock.                 Finally, the viability of the system to changes in certain key parameters has been evaluated. Overall, the system's economic performance is not jeopardized by different configurations and solely two factors, the cost of capital and the connection rate could put at risk the success of the undertaking.