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• Novel modelling framework allow spatiotemporal optimisation of energy systems. • Co-simulating regional power market model and local biomass and district heat model. • New detailed spatial optimisation of renewable gas and fuel production. • PtX shows promising economic-viability in the future. • Excess heat from biorefineries is efficiently used for district heating. This study conducts an integrated energy system assessment to evaluate pathways for using locally distributed sustainable biomass resources in the conversion to renewable gas and liquid biofuels in future integrated energy systems. A modelling framework with a detailed spatiotemporal representation is used, optimising the usage and transportation of local biomass resources for producing renewable gas and renewable liquid fuels through the OptiFlow model, along with the comprehensive power and district heating model Balmorel, integrating short-term dynamics in the long-term planning horizon. Results for a fossil-independent Danish energy system by 2050 show that production of bio-jet fuel in Denmark would impose high pressure on national biomass resources. Electrofuels, such as biomethanol, have economic viability and promising potentials. The results regarding renewable gas production show that anaerobic co-digestion of a mixed feedstock to produce biogas, which is further upgraded to biomethane using water scrubbing for CO 2 removal, would be the preferred option. Biorefineries are located near larger cities to benefit from economy of scale and access to large district heating networks, as excess heat from biorefineries could supply up to 21% of the national district heating demand. On the contrary, biogas plants would be located in the countryside, as the costs of transporting manure are a determining factor. Therefore, our study provides a novel modelling approach, which enables optimisation of geographical distributed resources for renewable gas and liquid fuel production, while taking synergies across energy vectors in account. [ABSTRACT FROM AUTHOR]

In the last decade, pit thermal energy storage (PTES) systems have been used as a large-scale heat storage solution in district heating systems due to their low specific investment cost and high storage efficiency. Despite the existing knowledge on thermal energy storage (TES) technologies, their economic and environmental impacts have not been quantified in the literature, and very few studies have studied PTES as part of the energy system. For this reason, the energy system model Balmorel was used to quantify the impact of TES on the energy system, particularly PTES, and compare it to the tank thermal energy storage (TTES) alternative. The investigation was focused on Denmark and its neighboring countries. It was found that it was only the energy systems using TES that could achieve carbon neutrality by 2050. The main reason was the added flexibility due to the energy storage that allowed the system to have a 35% higher PV capacity, 10% higher wind capacity, and lower levels of curtailment. Additionally, systems with TES had 2.4 €/MWh lower average heat price (with 24% lower peak price). When comparing PTES with TTES, it was found that PTES systems were more advantageous, achieving a 1.5 €/MWh lower average price of heat. • Integration of thermal energy storage in energy systems using the Balmorel model. • Sector coupling was included by modeling the power, heat, gas, and transport sectors. • Thermal storage enabled 10% lower average heat price and 24% lower peak price. • Thermal storage allowed high renewable utilization, limiting dispatchable production. • The impact of pit storages on the energy system was quantified and compared to tanks. [ABSTRACT FROM AUTHOR]