Modelling of renewable gas in the future energy system

The Danish government has set ambitious targets regarding the future exploitation of renewable energy in the Danish energy system. In many respects, the prospective increase in renewable energy resources (RES) will substantially impact the entire future Danish energy system. Renewable gas is a fuel that can contribute to the sustainable transition towards an energy system independent of fossil fuels in the longterm.

This study investigates the role of renewable gas production in a renewable based Danish energy system. To facilitate the modelling of renewable gas, improvements of the structure in the spatiotemporal optimization model OptiFlow is carried out. The OptiFlow model is hard-linked to the existing energy system model Balmorel, allowing modelling the gas chain from up-stream renewable gas production, through storage facilities to end consumers.

Balmorel is a bottom-up, deterministic, partial equilibrium model, which minimizes systems costs under perfect market conditions. The developments in OptiFlow enable modelling of various processing technologies, e.g. biological- and thermal- gasification as well as electrolysis technologies. The co-simulation of OptiFlow and Balmorel leads to the socio-economic optimal system, where investments and operations optimization is facilitated for the integrated electricity, district heating, and gas system.

The results of this study show that production of RE-gas is socio-economically attractive in all the investigated scenarios. Furthermore, the results show that RE-gas directly injected into the natural gas pipeline network is preferred. The analysis show that geographical allocation of resources has an impact on the results.

Moreover, it was shown that hydrogen was not produced in periods with high electricity prices.