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In a new weekly update for pv magazine , Solcast, a DNV company, reports that North America experienced a split in irradiance patterns across the continent in November.
Data analyzed by Solcast, via the Solcast API, shows that there was unusually high irradiance over large swaths of northeastern North America due to anomalous high pressure that kept Atlantic moisture offshore. In contrast, the Gulf Coast received noticeably lower irradiance as a result of atmospheric changes and cloud formation produced by the same high-pressure system.
Clear skies were recorded in the northeast, reaching irradiance levels up to 30% higher than the long-term average for November. It was an unusually strong and widespread anomaly that extended from Oklahoma (United States) to Quebec (Canada). The driving force for this high irradiance is the anomalous high pressure over the continental US that prevented Atlantic moisture and resulting clouds from affecting solar assets located in these regions.
The Gulf Coast experienced cloudier conditions from Florida to the east coast of Mexico, with irradiance around 20% lower than the long-term average for November. The anomalous high pressure system that increased insolation further north induced lower pressure in the Gulf of Mexico, causing increased atmospheric instability and cloud formation, reducing solar potential.
The Sierra Madre Occidental mountain range played an important role, protecting western Mexico from the humidity of the Gulf. The large disparity caused by the mountains can be seen in the daily average GHI data, with areas west of the mountains averaging 4-5 kWh/m2 throughout the month, in stark contrast to the 3-4 kWh/m2. m2 east of the mountains.
Despite the cloudy effects of the El Niño weather phenomenon on the US West Coast, a balance was achieved as the drying effects of the anomalous high pressure counteracted its effects. This pattern allowed US West Coast solar asset operators to continue enjoying typical November irradiance levels. However, further north along the West Coast, the same high-pressure system diverted Pacific moisture away from the continental United States toward British Columbia.
This deviation resulted in irradiance up to 40% lower than the long-term average in British Columbia. Although significant in relative terms, this is a small absolute reduction, considering that the total solar potential of this region is only 1 kWh/m2/day at this time of year.
Solcast produces these figures by globally monitoring clouds and aerosols with a resolution of 1 to 2 km, using satellite data and proprietary AI/ML algorithms . This data is used to drive irradiance models, allowing Solcast to calculate irradiance at high resolution, with a typical bias of less than 2%, and also cloud tracking forecasts. This data is used by more than 300 companies managing more than 150 GW of solar assets worldwide. |
