Added value functional energy storage from system and actuator perspective

In this research work, the contribution of functional energy storage technologies to fulfill the energy policy triangle (economic viability, environmental sustainability, and security of supply) is investigated for up to the year 2030. It is noted that the aspect of economic viability should consider both the system and the stakeholder perspectives. Besides classical storage technologies like pumped hydro storage, heat storage for the flexibilisation of combined heat and power (CHP) in district heating systems, Power2Heat, Power2Gas as well as flexibilisation of load in industrial processes and households are taken into account. The term ''Functional Energy Storage'' encompasses all these technologies. Firstly, wherever they can offer an added value, all use cases for storage are analysed. The analysis of the use cases show that through changes in market design, on one hand, demand for flexibility can be reduced whereas on the other hand, it can also allow for the access to more flexibility. Hence, changes in market design can also contribute to security of supply. Subsequently, the added value of storage technologies is evaluated with the help of an energy system model (''ISAaR'' = Integrated Simulation model for plant deployment and expansion planning with Regionalization). Within this model, unit commitment and expansion of units are simulated using linear programming. To identify differences between the system and stakeholder perspectives, taxes and fees that are incurred during operation of the units are taken into account for the stakeholder perspective whereas they are not for the system perspective. The energy system is modelled with an hourly resolution at the transmission level. Germany consists of 20 knots, Austria 8 knots and the other European countries each constitute one knot. All the weather dependent input data was based on meteorological data from the year 2012. For the system perspective, the used scenarios vary by means of grid and consumption of electrical energy. In Germany, the expansion of renewable energy sources is taken from the German grid development plan 2015. However, for onshore wind power production, timelines which result in full load hours of newly installed units of 3000 instead of 2000 are used. The given expansion path of renewables by the grid development plan leads towards a 75 % share of renewables by the year 2030. This is markedly more than what was stated in the coalition contract to form the federal government of Germany in 2013 (55 % by 2035). Simulation results show that until the year 2030, Power2Heat in district heating systems with a capacity of more than 8 GW, and the flexibilisation of load in industrial processes are all very cost effective from the system point of view. Though up to 8 TWh of curtailment is avoided by storage commitment, CO₂-Emissions increase. This can be attributed to an increase of operation hours of base load power plants. When taxes and fees are considered in modelling the stakeholder perspective, both the expansion and deployment of storage are reduced. This drives additional costs of up to several hundred million euros whereas at the same time, CO₂-Emissions are lowered by a small amount.