Price of Power System Stability

Control reserves are power generation or consumption entities that ensure balance of supply and demand of electricity in real-time. The reserves are procured through a market mechanism in which entities provide bids on power capacities and corresponding prices. We have been developing game theory, control and optimization methods to address efficiency of these markets.

by Weekly Spotlight on Energy Research

For a stable power grid, the supply and demand of electricity at all times need to be balanced. Control reserves, also referred to as ancillary services, ensure this balance in real-time.  With increasing volatile renewable sources of energy, the need for control reserves also has increased. This has motivated our research in two directions:

  1. Can aggregation of consumers be used as control reserves (external pagevideo on heat reserves in buildings)
  2. What are optimal market mechanisms and bidding strategies for control reserves?

With respect to the second question, Kamgarpour and her collaborators have been exploring market mechanisms with potential improvements. In the current pay-as-bid mechanism, since payments to winners are equal to their bid prices, a rational player may over-bid to ensure profit. As an alternative to pay-as-bid, we have been exploring the Vickery Clarke Groves (VCG) mechanism. This is one of the most prominent auction mechanisms, used for example in advertising by facebook.

In our work, we showed that the VCG mechanism applied to control reserves maximizes social welfare and ensures incentive compatibility. Incentive compatibility means that it is optimal for each participant to bid their true value. The preliminary results have been analyzed using Swissgrid market data. Several questions remain open and are subject of our current study: How do we ensure collusion and shill bidding will not occur? And how do aggregation of units optimally participate across the wholesale and the control reserve markets? For further information, please see our external pagerecently submitted article.

Enlarged view: Control reserves ensure real-time balance of supply and demand of electricity.
Control reserves ensure real-time balance of supply and demand of electricity. There is potential for consumers to enter the control reserve market if properly aggregated. Studying the market mechanism is important to ensure stability and efficiency of the grid.

The ESC Member involved in this project is Professor Maryam Kamgarpour member of the Automatic Control Laboratory. The Automatic Control Laboratory (Institut für Automatik, IfA) is a part of the Department of Information Technology and Electrical Engineering (D-ITET).

Professor Maryam Kamgarpour's research areas are:

Power grid system: Prfessor Kamgarpour's goal is to understand how advanced control algorithms could help in achieving a stable and secure grid despite increasing uncertainties from the renewable energy sources and the liberalised electricity markets. To this end, she works on developing theory and algorithms for control of large-scale systems accounting for uncertainties and multiple objectives. The tools used include distributed control and game theory. She currently leads an ERC project on this topic.

Formal methods and control: Maryam Kamgarpour has been working on stochastic hybrid systems as a framework to capture specifications defined by finite state deterministic automata for uncertain dynamical systems. Building on this framework, her vision is to develop provably safe feedback policies that can adapt to an underspecified changing environment to achieve complex specifications. The application addressed within this framework is search and rescue mission in uncertain environments.  

Air traffic system: Focus is on developing scalable optimal control algorithms for safe and fuel-efficient aircraft trajectory planning, taking into account environmental uncertainties. An interesting and challenging aspect of this optimal control problem is to ensure the developed algorithms are compatible with air traffic procedures so that they have high levels of human trust and acceptance.

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