Power & Renewables

Accurate Load Forecasting on a Rainy Day in L.A.

byRob Allerman

When you think about Los Angeles weather, you likely think of warm and sunny. In fact, L.A. is so sunny, it ranks No. 1 in total installed solar photovoltaic (PV) systems in the U.S., with more than 483.8 megawatts (MW) of capacity.

But what happens when it is cold and rainy?

Southern California recently experienced rainy weather and the CAISO under-forecasted 90% of the hours during the lookback period. This is likely because solar power was expected to increase during peak hours and reduce demand. But solar panels are not effective when it is cold and rainy, as seen in the charts below reflecting load forecast from Dec. 7-9.

Chart showing PRT and ISO load forecast, and actual versus forecast temperature

Over the past few years, ISOs, load forecasting companies, and utilities have had to learn to forecast and manage the California “duck curve” as solar power has increased and load decreases during the day. However, when it’s cold and rainy, the load returns to its normal pattern and increases during the day.

If the ISO or load forecasting company is not also forecasting behind-the-meter or adjusting for weather, utilities may be caught off guard if they don’t have thermal generation available to come on line during the middle of the day to meet that load.

Chart showing Enverus price forecast day ahead for SP-15 hub

Enverus’ PRT load forecasting solution combines weather with historical data to produce a more accurate forecast. This better prepares utilities and provides enormous opportunities for day-ahead and real-time traders. If the ISO is not forecasting behind-the-meter, day-ahead or real-time, prices will look much lower than the actual price (some of the price inaccuracies on the Dec. 7 were due to unit forced outages).

We expect to see additional weather in the coming months and want to ensure utilities are prepared and traders are informed with the most accurate information. To see how Enverus can play a vital role in the success of your load forecasting efforts, or to see the full power report we reference above, contact us using the form below.

Picture of Rob Allerman

Rob Allerman

Rob Allerman is Senior Director of Power Analytics at Enverus. Before joining Enverus, Rob was Head of North America Power Analytics at EDF Power Trading in Houston, Texas, and spent many years as a power analyst at Deutsche Bank. Rob also worked in the western U.S. for nearly 10 years at Power Utilities and started his career as a Hydrologist for the Federal Government.

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