Solar irradiance outlook in Eastern Mediterranean 2017

Regional solar irradiance data is analyzed in order to estimate the normalized output of solar power facilities in the region, considering the strong link between the two variables, as demonstrated in previous comprehensive study on PV facilities in Israel. The solar energy cumulative flux, measured at the IMS station in Bet Dagan (Central Coastal Plane) during 2016, was on average 5,520 Wh/m2 per day, which is 7.6% higher than the 1965-2014 multi-year annual solar flux average. In fact, the 2016 solar energy flux figure is the record highest measurement at Bet Dagan IMS station, which has been operating since 1965. 2017 and 2018 are also expected to show above average solar irradiance in the region. Increased solar irradiance on ground level is driving increased performance figures for PV facilities in the region - a phenomenon which may continue for some time.

Bet Dagan is the longest operating Israel Meteorological Service (IMS) station which has been measuring solar energy flux on ground level since 1965. The station is thus the most suitable for long-term analysis. Regional solar irradiance data is analyzed in order to estimate the normalized output of individual solar power facilities in the region, considering the strong link between the two variables, as demonstrated in previous comprehensive study on PV facilities in Israel. It should be emphasized that variance in solar flux on the ground level is mostly a result of regional weather and climate influenced by long-term trends in solar activity, planetary climatic shifts and more recently by anthropogenic causes; only to small degree variance in measured solar flux is a direct result of sun's solar output, which is relatively stable.

Figure 1. Solar irradiance measured at Bet Dagan in central Israel in monthly resolution during 2016 (orange) vs. the average for respective months obtained during 1965-2014 (blue).

The solar energy cumulative flux, measured at the IMS station in Bet Dagan (Central Coastal Plane) during 2016, was on average 5,520 Wh/m2 per day, which is 7.6% higher than the 1965-2014 multi-year annual solar flux average and is exceeding the standard annual deviation of ±4.0% during that period. In fact, the 2016 solar energy flux figure is the record highest measurement at Bet Dagan IMS station, which has been operating since 1965. Previously, in 2015, the solar energy cumulative flux was at 5,269 Wh/m2 per day, which is about 2.8% higher than the 1965-2014 multi-year average. The 2014 solar energy cumulative flux was at 5,399 Wh/m2 per day, as well higher than multi-year average.

2017 and 2018 are also expected to show above average solar irradiance figures in the Eastern Mediterranean region, continuing the high solar irradiance trend of - similar to the period of late 1960s and early 1970s or even exceeding it. Increased solar irradiance on ground level is driving increased performance figures for PV facilities in the region - a phenomenon which may continue for some time. Among possible factors to alter this projection is an unexpected change in solar activity or a powerful volcanic eruption in Equatorial regions at an intensity of VEI 5.0 or above.