As part of our ongoing support for the U.S. Energy Information Administration (EIA) and other government agencies, OnLocation has been studying the potential impact of large amounts of solar generation on grid stability as it relates to the National Energy Modeling System (NEMS), as described in a previous blog dated May 25, 2016. The issues stem from the timing of solar generation during the day, particularly in months when electricity demand is relatively low such as early spring before air conditioning is needed. The potential impact on the grid from the high daytime solar generation on days with low electricity demand and the corresponding steep reduction in solar in the evening has been dubbed the “duck” issue by the California Independent System Operator (ISO) and has been the subject of speculation in recent years. The duck phenomenon was evidenced this March in California when the system average hourly prices dipped below $0 per megawatthour (MWh) in the morning hours, as described in last week’s EIA Today in Energy article.