Impact of Market Timing on the Profit of a Risk-Averse Load Aggregator

Non-generating resources such as thermostatically controlled loads (TCLs) can arbitrage energy prices and provide balancing reserves when aggregated due to their thermal energy storage capacity. An aggregator that wants to quantify this flexibility in order to place optimal bids before gate closure, would be affected by market timing. The market timing can be quantified by parameters such as lead time and contract period. This paper explores the impact of market timing on TCL aggregate power consumption and reserve capacity bids and quantifies trade-offs between market timing and flexibility. We first optimize the power consumption and reserve capacity offers at given lead times and contract periods, varying from 24 hours ahead to real-time. We then introduce uncertainty in prices and TCL availability, formulate a two-stage chance-constrained optimization problem of a risk-averse aggregator, implement it on a rolling horizon basis, and evaluate how the trade-offs change. The results show that shorter lead times and contract periods positively impact TCL profit as well as flexibility if the prediction horizon is sufficiently long. The proposed method can be used by aggregators to decide on optimal bids and incentive payments to consumers to reward flexibility.