What's behind? Our (and other)
research projects showed that satellite derived radiation data is the most accurate source for solar radiation data for almost any place on Earth, where no direct radiation measurements are available.
We have therefore integrated satellite radiation sources into our intraday and day ahead forecast, as well as into our historic time series. The graph shows the improvement (as MAE = Hourly mean absolute error):
> past forecast: NEMS-30 = average 18% MAE
> new forecast: MOS = average 15% MAE
> best-guess: SAT-OBS = average 12% MAE
> local reality (OBS) = zero line 0% MAE
Only with measurements (OBS) will it be possible to determine precisely how much radiation was actually received at the location. These measurements are rarely available and often biased due to shading or soiling In the absence of measurements, SAT-OBS is the best guess about reality, i.e. "as-good-as-it gets". This data is available for 80% of the Earth's surface. And our new forecast takes 50% of the error of simulation out. Got it? if not, write us.