Field Testing of Automated Demand Response for Integration of Renewable Resources in California’s Ancillary Services Market for Regulation Products

Increasing renewable generation resources supply electricity to 33% by 2020 in California will require solving several problems simultaneously. In California, 33% penetration of renewable generation resources propose four major challenges:

1. unpredictable and steep ramps;
2. making up for errors in forecasting these resources;
3. intra-hour variability; and
4. over generation in the middle of the night.

Storage and demand response are being proposed as ways to address these challenges. Following successful tests using demand response for non-spinning reserves in California Independent System Operator’s ancillary services market, we explored the use of demand response for regulation up and down products in the same market. Regulation is the capability to inject or withdraw power from resources in response to automatic generator control signals to meet the Area Control Error needs of the Independent System Operator. Resources participating in regulation are characterized and certified to meet certain requirements. The objectives of this project were to evaluate if the demand response resources could meet the requirements to replace the generators in this market and if OpenADR would be able to meet the communication speed requirements. Three facilities were recruited to the project: two campuses and one agricultural pumping station. Each site was equipped with an OpenADR client that could receive the automatic generator control signals converted into OpenADR information exchange model. The results showed that

1. the pseudo generator model did not work well for demand response resources;
2. converting automatic generator control signals to OpenADR signals did not introduce significant communication delays;
3. accuracy of load forecasts may introduce significant problems with demand response participation; and
4. latencies due to the facility control system may be a major barrier.