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GHI Historical Period Used for Energy Production Assessments
C. Hidalgo
PV Systems – Modelling, Design, Operation and Performance
Subtopic: Solar Resource and Forecasting
Event: 38th European Photovoltaic Solar Energy Conference and Exhibition
Session: 5BV.4.16
ISBN: 3-936338-78-7
0,00 EUR
Document(s): poster


The use of the Global Horizontal Irradiation (GHI) has become standard in the PV industry for the energy production assessment. GHI is typically assessed with long term historical period using satellite data with more than 20 years in many cases. The most accepted approach is using as many years as possible to create the long term GHI for the energy assessment, at least more than a solar cycle of 11 years. However, this approach may not be adequate when the trend of the last 10-11 years is different from the long-term historical average. DNV has been involved recently in many projects in the Iberian Peninsula as per Figure 1 below. DNV has compared the long-term historical average for each of the projects with the last 11-year period to identify any pattern of increasing GHI that should be considered in certain areas of the Iberian Peninsula. A discussion on the possible reasons for the detected deviations and recommendations for energy Production Assessment in those regions is also provided.