Matias Negrete-Pincetic

Ashutosh Nayyar, Matias Negrete-Pincetic, Kameshwar Poolla et al.

As the proportion of total power supplied by renewable sources increases, it gets more costly to use reserve generation to compensate for the variability of renewables like solar and wind. Hence attention has been drawn to exploiting flexibility in demand as a substitute for reserve generation. Flexibility has different attributes. In this paper we consider loads requiring a constant power for a specified duration (within say one day), whose flexibility resides in the fact that power may be delivered at any time so long as the total duration of service equals the load's specified duration. We give conditions under which a variable power supply is adequate to meet these flexible loads, and describe how to allocate the power to the loads. We also characterize the additional power needed when the supply is inadequate. We study the problem of allocating the available power to loads to maximize welfare, and show that the welfare optimum can be sustained as a competitive equilibrium in a forward market in which electricity is sold as service contracts differentiated by the duration of service and power level. We compare this forward market with a spot market in their ability to capture the flexiblity inherent in duration-differentiated loads.

Ashutosh Nayyar, Matias Negrete-Pincetic, Kameshwar Poolla et al.

The integration of renewable generation poses operational and economic challenges for the electricity grid. For the core problem of power balance, the legacy paradigm of tailoring supply to follow random demand may be inappropriate under deep penetration of uncertain and intermittent renewable generation. In this situation, there is an emerging consensus that the alternative approach of controlling demand to follow random supply offers compelling economic benefits in terms of reduced regulation costs. This approach exploits the flexibility of demand side resources and requires sensing, actuation, and communication infrastructure; distributed control algorithms; and viable schemes to compensate participating loads. This paper considers rate-constrained energy services which are a specific paradigm for flexible demand. These services are characterized by a specified delivery window, the total amount of energy that must be supplied over this window, and the maximum rate at which this energy may be delivered. We consider a forward market where rate-constrained energy services are traded. We explore allocation policies and market decisions of a supplier in this market. The supplier owns a generation mix that includes some uncertain renewable generation and may also purchase energy in day-ahead and real-time markets to meet customer demand. The supplier must optimally select the portfolio of rate-constrained services to sell, the amount of day-ahead energy to buy, and the policies for making real-time energy purchases and allocations to customers to maximize its expected profit. We offer solutions to the supplier's decision and control problems to economically provide rate constrained energy services.