On Friday, March 20, 2015 a solar eclipse will pass over Europe between 8:40AM and 12:50PM CET. The reduction of solar radiation during these hours is expected to have an impact given the 89 GWs of solar-powered generation capacity installed across the continent. The total impact to the continental European power system is an estimated drop of 34 GWs around 10:30AM during the eclipse (ENTSOE).

In mid-February, the Transmission System Operators prepared a report with impact analysis of the solar eclipse, including a linear extrapolation of capacity and the expected reduction in solar production output at the height of the eclipse. The table below shows the expected reduction in solar production at the height of the eclipse, as well as estimated solar installed capacity for top European countries.

In September of 2014, Genscape launched a solar model to cover the Italian power market. This model gives an estimation of solar power production every 15 minutes for the six geographic market zones as well as a total for Italy. A week out from the eclipse, Genscape's models were run to simulate a warm/sunny spring day and the production effect.

Due to the trajectory of the eclipse, the affect is bigger the further north you go. In Italy, the largest solar capacity is located in the North, so the impact will be larger than perhaps expected if looking at Italy from a total production perspective. The eclipse is expected to begin at 09:24AM and last 2 hours and 20 minutes. The time of maximum phase is 10:33AM, and by 11:45 solar power is expected to be back to normal for a typical spring day

Genscape provides its Italian Power RT customers with a solar production estimate every 15 minutes. The production estimates are modeled down to the two-digit zip code level and are aggregated for customer use to the market zone and total Italian levels. The model structure uses: published capacities; solar production data from PV installation companies; irradiance and weather readings and forecasts, and temperature readings from Genscape's proprietary measurement units.

Solar capacity in Italy has been increasing between one and three percent on a monthly basis according to Atlasole, the division of Gestore Servizi Energetici (GSE) that supports photovoltaic information. GSE promotes and supports renewable energy sources in Italy.

In 2012 capacity was approximately 13 percent of the total installed net capacity and has increased a further 10 percent since the end of 2012. Genscape uses updated capacity, tied to the two-digit zip code as the basis for its production forecast.

As part of the model build, Genscape used public solar data for just under 300 panel installations and 99 MWs of capacity. This data is available through a prominent PV system vendor and offers coverage of over 75 percent for each of the six geographic market zones.

Irradiance forecasts and other weather variables for 75 weather stations were interpolated to the two-digit zip code and then assigned to the market zones. Solar irradiance is a measure of the power per unit area on the Earth's surface produced by the sun. The model assumes that photo-voltaic panels across Italy are the normal 30 degree tilt south-facing installation.

Genscape monitors 79 percent of the installed power generation capacity in Italy. These monitors also capture weather variables which are captured every 15 to 30 minutes as well as whenever there is a significant change on the power transmission line being monitored.

During the model build, 48 of the 287 monitors currently installed to measure power generation at traditional power plants were correlated to add to the weather station coverage in certain zip codes. Weather readings from Genscape's measuring units increased the accuracy in some zip codes by 20 percent.