Hybrid energy networks and electrification of district heating under different energy system conditions

As electricity systems world-wide are transitioning into increasing levels of variable renewable electricity sources, such as wind power and photovoltaics, increased electrification of other energy sectors has shown to be important for allowing a resource- and cost-efficient integration of these sources. Research has found electrification of district heating to be one of the more promising energy sectors for electrification in relation to integrating variable renewable electricity sources, as district heating allows for the utilization of varied use of different energy conversion technologies and low-cost energy storage solutions. Historically, district heating has mainly been interconnected to the electricity system via combined heat and power units, though research have found that with increasing levels of variable renewable electricity sources the need for electricity consuming conversion units, such as heat pumps, are becoming more important. In this, the national energy system effects of electrification of the district heating sector are investigated. Two future energy system scenarios for two different countries, being Austria and Denmark are made: one with a high degree of district heating utilization and one with a lower degree of district heating utilization. Both countries are expected to utilize increasing levels of variable renewable electricity sources, though the level and type of variable renewables are different due to differences of e.g. in availability hydro power solutions within the countries and the wind and solar resources available. As such, these two countries provide different perspectives on how electrification can be understood under different conditions

PtX Sector Coupling and LCA:Working Group 1A – summary of work

This publication is part of the project PtX Sector Coupling and LCA (Pool 1) funded by Innovation Fund Denmark in the Partnership MissionGreenFuels. The project had two purposes: 1. To further develop existing energy systems and LCA tools, methodologies and models better to determine the optimal PtX integration into the green transition2. To use these models for assessments relevant to defining the optimal locations of new plants based on grid capabilities, market forecasts, biomass and carbon availability and including sector coupling and co-optimisation of gas, electricity, hydrogen and district heating.To investigate this, the project was divided into 3 working groups focusing on different aspects. The work presented in this report summarises the findings of Working Group 1A: Local plan level. The focus of working group 1A was PtX at plant level, with a special focus on integrating excess heat from these into district heating systems. This was done by listing planned and theoretical PtX projects that included the use of excess heat for district heating, investigating the potential for flexibility in the operation of PtX plants, creating a case study of the district heating system effects of utilizing excess heat from PtX, and visualizing results for a wider audience. Each of these are described in the report

The role of thermal energy storages in future smart energy systems

This paper conducts an in-depth energy systems analysis on the role of thermal energy storages in Denmark's transition to a fully decarbonized Smart Energy System. Using the EnergyPLAN software and national-scale energy system scenarios, the research examines how the use and impact of thermal energy storages evolves during this transition. Findings indicate that thermal energy storages play an important role in minimizing fuel consumption, curtailing losses, and in improving the overall energy-efficiency and balance of supply and demand. Initially, it primarily lowers fossil fuel use, potentially by 3 TWh per year. As renewable energy increases in the system, its main focus shifts towards reducing excess electricity via power-to-heat and conserving biomass, cutting up to 1 TWh of excess electricity annually through added flexibility. Variable system costs potentially decrease by 17–67 million EUR yearly, though economic feasibility depends on the phase of the transition when investment costs are included. In a future smart- and fully decarbonized system, the economic feasibility is heavily affected by energy prices along with other heat- and storage alternatives and flexible consumption. This leads to the novel understanding that the role of thermal energy storage changes along with the transition of the energy system