  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. Based on a performed survey of Swedish
single- and two-family dwellings with electric heating, this paper quantifies
the potential of TCLs to provide reserves to the power system in Sweden. To
this end, dwellings with heat pumps and direct electric heaters are modeled as
thermal energy storage equivalents that can be included in a linear two-stage
problem formulation. We approach the operational flexibility of the TCLs by
modeling a risk-averse aggregator that controls decentralized TCLs and aims to
maximize its own profit. The results show a potential of 2 GW/0.1Hz averaged
over a year, and up to 6.4 GW/0.1Hz peak capacity. Based on a sensitivity
analysis we derive policy implications regarding market timing and activation
signal.
