  The deepening penetration of variable energy resources creates unprecedented
challenges for system operators (SOs). An issue that merits special attention
is the precipitous net load ramps, which require SOs to have flexible capacity
at their disposal so as to maintain the supply-demand balance at all times. In
the judicious procurement and deployment of flexible capacity, a tool that
forecasts net load ramps may be of great assistance to SOs. To this end, we
propose a methodology to forecast the magnitude and start time of daily primary
three-hour net load ramps. We perform an extensive analysis so as to identify
the factors that influence net load and draw on the identified factors to
develop a forecasting methodology that harnesses the long short-term memory
model. We demonstrate the effectiveness of the proposed methodology on the
CAISO system using comparative assessments with selected benchmarks based on
various evaluation metrics.
