Simon Koopmann

Evaluating regulatory and market frameworks for energy storage deployment in electricity grids with high renewable energy penetration

Investment volumes in renewable energies in Germany are far ahead of the necessary infrastructure to integrate them into both the electricity market and the grid. For storages and other technologies offering flexibilities the current regulatory framework and the market design in Germany remain a barrier for upcoming investments. In this paper regulatory barriers for an economically efficient energy storage deployment are presented and evaluated using a generic optimization model for a multifunctional operation of storage technologies on electricity markets capable to consider different market and regulatory design changes. Due to the rising significance of grid restrictions for the integration of intermittent resources and upcoming new innovative storage technologies on distribution grid level, the electricity grid was integrated into the model. Such an approach enables a quantitative analysis of interaction between market operation and grid congestion. This is shown using a 110kV high-voltage grid in the North of Germany as a representative congested grid with ongoing curtailments due to high wind energy penetration. Storage technologies - and also other measures as demand-side and generation management - will need a flexible market and a sophisticated regulatory design in order to significantly add value to the future energy system.

Integration of stationary and transportable storage systems into multi-stage expansion planning of active distribution grids

The integration of storage systems is a promising option to reduce or defer conventional expansion measures in distribution grids. In this paper an integrated approach for grid expansion planning and deployment of permanent stationary and temporary transportable energy storage is presented. In order to adequately represent storage systems, multiple investment stages and a sophisticated evaluation process are considered. The latter takes time-coupling storage behavior and multifunctional storage operation into account. The proposed approach uses a genetic algorithm with modified operators and linear and non-linear programming models for the fitness evaluation of storage and grid operation. The results of a test case demonstrate the validity of the proposed algorithm.

An AC power flow linearization for power system optimization using linear programming

This paper presents a method for the linearization of the non-linear power flow equations, which can be used in mixed integer linear optimizations. The power flow equations are linearized around an operating point using the Taylor approximation. The linearization implies an approximation error, which can be reduced iteratively by modifying the operating point. In addition to existing approaches, controllable assets like voltage regulated transformers or phase shifters are integrated into the linearized grid constraints. The model is exemplarily applied to an operation planning model of distributed energy resources considering grid restrictions. The results show that this approach reduces the approximation error significantly and that it is robust for different real distribution grids as well as for different generation and load scenarios.

Method for modelling fluctuating energy generation plants for the assessment of their impact on medium and low voltage grids

This paper describes a method for taking the forecasting uncertainty into account when assessing the impact of volatile generation on power grids. To this end the generation of feed-in scenarios for generation plants that include the uncertainty of the weather forecast is described. With a three-step model that firstly forecasts local weather parameters and, secondly, generates scenarios for these parameters, thirdly, a reduced number of resulting feed-in profile scenarios for each plant is computed. With these scenarios the assessment of the grid-impact of the plants can be calculated taking into account the uncertainty of the prognosis. In a case study, feed-in profiles for the plants in an exemplary region are generated which can be used for an assessment of the grid impact in this region using probabilistic load flow calculation.

Analysis of alternative transition paths for the German energy system

On EU-level and especially in Germany there are strong efforts to meet the targeted climate goals. However, finding the most efficient transition path from todays energy system to a sustainable one remains a challenge. Therefore, in this paper different transition paths for the German energy system based on gas instead of lignite power plants are presented and discussed. Those paths are compared with the most likely development of the German energy system based on todays energy policy (baseline scenario). The assessment is based on a model, the European Multimodal Market Simulation (EMMS). Without lignite power plants, Germany will always comply with the climate goals. Most investigated scenarios lead to higher total system costs than the baseline scenario. Cost reductions are only achieved in case of a low gas price and a high reduction of renewable capacities.