Analysis of Technology Options to Balance Power Generation from Variable Renewable Energy. Case Study for the German Energy System with the Sector Coupling Model REMod
The German Federal Government committed to drastically reduce its greenhouse gas emissions as part of its climate change mitigation strategy. This will lead to an increasing deployment of variable renewable energy sources (VRE). However, the expansion of VRE is only reasonable if their intermittent electricity generation can be effectively integrated into not only the power sector but also the transport sector and into the supply of space and process heat. To achieve this, the energy system needs to become more flexible while also being able to cope with changing weather influences. In this work, load balancing options for the German energy system are analysed based on an enhancement of the Renewable Energy Model REMod. The model is designed to determine a cost optimal configuration of the energy system under consideration of an exogenously set limit of energy-related CO2 emissions. In an integrative approach it depicts interdependencies between all implemented technologies and sectors of the energy system in hourly resolution. Special attention is given to power plant ramping behaviour, the variation of up to five different weather data sets, the implementation of driving profiles and charging strategies for electric vehicles as well as to the heat-controlled or power-controlled operation of heat generators in combination with thermal energy storage. According to the results, highly flexible gas turbine power plants are becoming increasingly important as the expansion of VRE proceeds. Power plants that require several hours of start-up time exhibit yearly efficiency losses of up to 6% of their nominal efficiency increasing their emissions and making them less profitable overtime. Furthermore plant operation and configuration of the energy system are substantially affected by underlying weather data. It is found that calculations based on one specific data set exhibit variations in costs and system configuration of up to 15%. Random data distribution over the observation period favours the refurbishment of buildings, the installation of more efficient technologies as well as the deployment of hydrogen-based technologies. An analysis of the motorised private transport shows that battery electric vehicles are a promising option to achieve the set emissions reduction targets, especially when they are charged in a controlled way. As for the supply of space heat and domestic hot water, heat grids and electric heat pumps represent key technologies to achieve the emission reduction targets. The controlled charging of electric vehicles and the power-controlled operation of heat generators with thermal energy storage by demand-side management (DSM) is found to be increasingly beneficial to the energy system as the set CO2 reduction targets become more ambitious. It is shown that part of thermal power plant generation capacity, stationary power storage systems and Power-to-Gas plants can be substituted by DSM. Power curtailments as well as imports of electricity or synthetic fuels from abroad would be decreasing. In addition to lowering the total system costs, it is found that DSM efficiently integrates power generation from VRE, reducing Germany's energy dependence on other countries.
Zugl.: Freiburg, Univ., Diss., 2019