Load Management Strategies to Support Grid Integration of Intermittent Renewable Resources Paulina Jaramillo and Lester Lave

Given the intermittent nature of wind and solar power Energy storage and back-up generation may be needed. Alternatively, non-essential loads can be turned on and off to match varying energy supply.

Load management programs have been designed in the past by ISOs To minimize spikes in electricity prices and to support grid stability – CAISO: Load (or aggregate loads) allowed to participate in day-ahead and real-time market and are dispatched by ISO if needed. – NYISO: 4 programs. 2 allow the ISO to ask large scale consumers to reduce demand 1 allows loads to participate in the day-ahead market 1 allows loads to participate in the ancillary service market

Utility-based load management programs: Pricing Plans: – Time-of-Use rates – Critical Peak Rebates – Critical Peak Pricing – Real Time Pricing Direct Load Control

Critical issues with programs that try to reduce load: The response time associated with each mechanism: – Residential consumers may respond within seconds of signal. – Industrial consumer may need to be scheduled in advance. The duration of the response – Load management programs may not be appropriate for reducing load for long periods of time.

The goal of load reduction programs: Reduce the need to build new power plants and new transmission lines. No much emphasis on supporting renewable energy integration.

For Wind and Solar Integration Load management programs that reduce load may be necessary at times when there is no power production. Load management programs may also be needed to schedule loads at times of high wind and solar generation.

When power production is higher than load Locational marginal prices go down (even negative). For now this seems to have been enough at current wind levels. Will this mechanism be sufficient with larger percentages of wind (or solar) in the system?

Other Mechanisms to increase load? Electric vehicles Direct control of devices such as water heaters. Pricing and tariff mechanisms that encourage scheduling demand at times of high wind and solar generation

Research Questions: What types of load management strategies are better suited to support renewable integration? Are ISO level strategies better suited than utility-based strategies? What is the role of load reducing and load dispatching strategies? Under which circumstances are market mechanisms, like time-of- use pricing, suitable as means to support renewable integration? What role should direct load control strategies play in supporting renewable integration? And, if direct load control strategies are to be used, do we know enough about the characteristics of the loads. How do these load management strategies affect grid reliability when paired with renewable energy generation? How do load management strategies compare to other strategies designed to deal with the intermittency associated with wind and solar power?