PJM is proposing a change to the way it estimates demand response in its load deliverability analysis.

Current practice looks at the amount of DR that has cleared in the last Base Residual Auction to project DR available five years in the future.

But Tom Falin, PJM manager of resource planning, told the Markets and Reliability Committee on Thursday that a significant amount of DR that clears the auction is replaced by other resources before the delivery year arrives. In the 2014/15 year, 46.5% of the DR assumed to be available had been replaced by non-DR resources.

“Our conclusion was that the assumption we’ve been making now for several years does not seem to produce an accurate forecast of DR,” he said.

PJM proposes basing future forecasts on an average of the final amount of committed DR for the most recent three years. The average would be expressed as a percentage of the zone’s 50/50 summer peak forecast for application to future years’ demand.

The model will take into account committed DR that is obligated to respond in an emergency, not all registered DR, Falin said.

Members agreed that the proposal is an improvement over the current model but that it likely would need to be modified in the future.

The MRC and the Planning Committee will be asked to endorse the revisions at their March meetings.