Solar time or legal time in hourly values?

[RicardoMoreno]

Good morning,

I'm running simulations for a self-consumption PV installation and in order to calculate a financial model I need to square hour-per-hour production and consumption with the electricity price according to Spanish legislation, which is rather complicated. Basically, there are 6 different prices which change depending on the hour of day, weekends, the month, and national bank holidays (please see the image I attach below if you're curious).

I'm wondering if the hourly simulation results exported to Excel from PVsyst show production in the solar hour or in "legal" hours, which in Spain can have a 2-hour difference at times, so that for example 3pm could actually be 1pm, and the prices for electricity at those two times can sometimes vary significantly and thus impact the project's NPV / IRR.

Thanks in advance for your support!

 

[Hizir Apaydin]

Dear Ricardo,

The basic reference time used in PVsyst is the legal time, which usually corresponds to the Winter Time of the country.

You can have more information about the time definition in PVsyst in this link: https://www.pvsyst.com/help/time_definition.htm

This means that the hour selection for the pricing in the economic evaluation tool correspond to your local legal clock, you don't have to perform any manual shift:

However, to take into account the time difference due to the transition to summer time, you have to set the time change dates in "Daylight saving time" of the economic evaluation as this information is not available in PVsyst and can be different for each country of the world. Thus PVsyst will automatically perform the one hour shift after this date and the correct hour will be taken into account for the pricing.