Towards energy security by promoting circular economy: A holistic approach

Dependence on fossil fuels, coupled with continuous supply disruptions by the most important natural gas suppliers, has jeopardized the energy security of most European countries. Therefore, determining the regions that can significantly increase their natural gas independence through the circular economy of their wastes is more important than ever. This work presents a multi-scale analysis to determine the possibility of implementing a circular economy towards reducing the regions dependency on fossil natural gas. A holistic approach is used to evaluate the availability of waste (manure, municipal solid waste, sludge, and lignocellulosic waste) and model the waste treatment processes (gasification and anaerobic digestion), together with a techno-economy analysis of the infrastructure required. A facility location problem optimizes the selection of the technology, the production capacity and the location of the facilities, according to the available budget. The analysis is focused on Spain, where, at the national level, an investment of 9458 M euro and an operating cost of 5000 M euro per year would allow covering 35% of the natural gas demanded. The regional analysis shows that a total of 19 provinces can be self-sufficient with this budget. These provinces have a high biomethane production potential through lignocellulosic waste gasification and a low demand for natural gas. Since energy is a basic commodity, the ability to produce enough biomethane to cover the entire demand for natural gas gives waste valorization strategic importance at both the social and economic levels.

Automated summary

Dependence on fossil fuels and supply disruptions by natural gas suppliers pose a threat to the energy security of European countries. Therefore, analyzing the potential of a circular economy to reduce reliance on fossil natural gas is crucial. This study evaluates the availability of waste and models waste treatment processes as well as analyzing the necessary infrastructure and optimizing the technology and location for waste valorization. The results show that Spain has the potential to cover 35% of its natural gas demand through a circular economy approach, with 19 provinces becoming self-sufficient in natural gas.