Time Series and TMY data

Energy production obtained via use of TMY P90 data is higher in some months than that obtained via use of TMY P50 data. Is this normal?

Modified on: Tue, 17 Jan, 2017 at 16:02

When selecting months for TMY P50 generation, we try to choose months from multi-year time series that are close to the monthly averages.

When selecting months for TMY P90, the criteria is that yearly sum should be a conservative value. However, all months in the TMY P90 dataset need not have lower values than the long-term average monthly value.

Indeed in real situations, if we look at real data with low yearly irradiation conditions, it is almost impossible to find a year when all months are lower than the long-term average (the only exception can be year following huge volcano eruptions such as the Pinatubo eruption).

More information about the Solargis TMY methodology can be seen here: http://solargis.com/support/knowledge-base/methodology/tmy-generation/

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