Evaluating battery interactions with the electricity grid in battery energy storage systems
Christian van Someren defended his PhD thesis at the Department of Electrical Engineering on June 11th.
As countries pursue energy transition policies, electricity grid congestion is increasingly becoming a bottleneck that slows down new developments. Batteries could be a solution to reduce grid congestion, but they could also worsen the issue. The Battery Energy Storage Evaluation Method (BESEM) was developed to evaluate how batteries interact with the electricity grid and determine how different policies and regulations can affect these interactions. In his PhD research, Christian van Someren applied the BESEM to case studies to gain insight into battery performance and battery grid. The results of this research can be used to solve grid congestion problems.
The BESEM that uses in his research, works by modelling sections of the electricity grid in detail. Grid topology, consumer load, generation profiles and battery (dis)charge profiles are considered in these models. In addition, batteries are also modelled in detail, taking battery characteristics, electricity markets and different battery control strategies into account. These two systems are interlinked so they can influence one another. For example, the electricity grid model can identify points of congestion, which can tell how batteries should be deployed to address these issues. By iteratively simulating these two systems, it is possible to derive solutions to grid congestion problems.
Evaluating battery system designs
Next to that, the impact of the batteries on the grid can be evaluated in the electricity grid model and the battery deployment schedule can be fine-tuned with this information to improve battery performance and minimize grid congestion. This way the BESEM can be used to evaluate battery system designs, considering battery performance and battery grid impacts. Christian van Someren focused on battery performance and battery grid in his research. He did this by applying the BESEM to case studies and that led to interesting findings.
Reducing grid congestion
First of all, the studies showed that as the energy transition proceeds, the simultaneity of new electric technologies will drive up grid capacity requirements and the storage capacity of any batteries used to support the grid. Therefore, it is important to investigate ways to reduce simultaneity before considering batteries as a sole solution to grid congestion problems. When batteries are used for grid congestion management, it鈥檚 also important to consider the impacts of simultaneity on battery sizing. Next to that, the research showed that batteries have the potential to reduce grid congestion, but only if they are properly regulated/controlled. This may require changes to existing regulations to allow distribution system operators to override normal battery operations at critical moments. In addition, using batteries for grid congestion management can come with an opportunity cost for the battery owner. These costs must be taken into consideration for any battery incentive/compensation schemes.
Regulating batteries
Passive battery controls, such as constraining battery power, can be nearly as effective as active battery controls, such as directly overriding normal battery operations, at reducing grid congestion in certain situations. This implies that regulating batteries may be an effective means of benefitting the grid without the need for expensive and complicated communication infrastructure. In conclusion, batteries alone will not solve grid congestion problems, but they can play an important role in deferring grid reinforcement, and thereby support the energy transition if the findings from this research are considered.
Title of PhD thesis: Supervisor: Prof. Han Slootweg