Abstract:
The increasing use of renewable energies as a source of electricity has led to a fundamental
transition of the power supply system. The integration of ?uctuating weather-dependent energy
sources into the grid already has amajor impact on its load ?ows. As a result, the interest in forecasting
wind and solar radiation with a suf?cient accuracy over short time periods (<4 h) has grown. In this
study, the short-term forecast of the effective cloud albedo based on optical ?ow estimation methods
is investigated. The optical ?ow method utilized here is TV-L1 from the open source library OpenCV.
This method uses a multi-scale approach to capture cloud motions on various spatial scales. After the
clouds are displaced, the solar surface radiation will be calculated with SPECMAGIC NOW, which
computes the global irradiation spectrally resolved from satellite imagery. Due to the high temporal
and spatial resolution of satellite measurements, the effective cloud albedo and thus solar radiation
can be forecasted from 5 min up to 4 h with a resolution of 0.05. The validation results of this method
are very promising, and the RMSE of the 30-min, 60-min, 90-min and 120-min forecast equals 10.47%,
14.28%, 16.87% and 18.83%, respectively. The paper gives a brief description of the method for the
short-term forecast of the effective cloud albedo. Subsequently, evaluation results will be presented
and discussed.
