The purpose of this paper is to quantify the potential for plug-in electric vehicles (PEVs) to meet operating reserve requirements associated with increased deployment of wind and solar generation. The paper advances prior PEV estimates in three key ways. First, we employ easily implementable scheduling strategies with very low centralized computing requirements. Second, we estimate PEV availability based on data sampled from the National Household Travel Survey (NHTS). Third, we predict regulation demand on a per minute basis using published models from the California ISO for 20% and 33% renewable electricity supply. Our key results are as follows: First, the amount of regulation up and regulation down energy delivered by PEVs can be balanced by using a hybrid of two scheduling strategies. Second, the percentage of regulation energy that can be delivered with PEVs is always significantly higher than the percentage of conventional regulation power capacity that is deferred by PEVs. Third, regulation up is harder to satisfy with PEVs than regulation down. Fourth, the scheduling strategies we employ here have a limited impact on load following requirements. Our results indicate that 3 million PEVs could satisfy a significant portion-but not all-of the regulation energy and capacity requirements that are anticipated in California in 2020.