Investigaciones y Recursos Solares Avanzados

Typical Meteorological Year based on Solar Radiation Data (TMY2, TMY3)





TMY hourly time series + meteorological variables.

TMY 10 minute interval time series + meteorological variables.




A PXX denotes the annual energy production level that is reached with a probability of XX%. Hence, P95 means: There is a chance of 5% that the P95 level will not be reached. P50 of course is the base case, as there is a fifty-fifty chance it will be exceeded.

For instance, if the annual energy production (base-case) is 200kWh and overall uncertainly is σ=9%, then the P95 is at 173kWh while the P75 is at 192kWh. With more uncertainty, those values decrease!

The PXX values are widely used by potential investors and banks as basis for financing decisions.

Typically, banks will apply the P90 or P95 level for their revenue forecast in order to determine if the interest cover is sufficient. Equity investors on the other hand may use the P75 or even P50 levels. However, as exceedence probabilities go lower, yield expectations of the investors will increase. While banks may lend money based on P95 level at 5%, an investor that bases their financing decision on the P50 case will expect more like 15%.

More uncertainly results in lower PXX levels and therefore higher cost of capital, as investors have to assume more risk.



P50, P75 and P90 series based from TMY hourly.



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Last update: 06/01/2016


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