@inproceedings{24551,
  abstract     = {{Access to precise meteorological data is crucial to be able to plan and install renewable energy systems 
such as solar power plants and wind farms. In case of solar energy, knowledge of local irradiance and air temperature 
values is very important. For this, various methods can be used such as installing local weather stations or using 
meteorological data from different organizations such as Meteonorm or official Deutscher Wetterdienst (DWD). An 
alternative is to use satellite reanalysis datasets provided by organizations like the National Aeronautics and Space 
Administration (NASA) and European Centre for Medium-Range Weather Forecasts (ECMWF). In this paper the 
“Modern-Era Retrospective analysis for Research and Applications” dataset version 2 (MERRA-2) will be presented, 
and its performance will be evaluated by comparing it to locally measured datasets provided by Meteonorm and DWD. 
The analysis shows very high correlation between MERRA-2 and local measurements (correlation coefficients of 0.99) 
for monthly global irradiance and air temperature values. The results prove the suitability of MERRA-2 data for 
applications requiring long historical data. Moreover, availability of MERRA-2 for the whole world with an acceptable 
resolution makes it a very valuable dataset.}},
  author       = {{Khatibi, Arash and Krauter, Stefan}},
  booktitle    = {{Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition (EUPVSEC 2021)}},
  isbn         = {{3-936338-78-7}},
  keywords     = {{Energy potential estimation, Photovoltaic, Solar radiation, Temperature measurement, Satellite data, Meteonorm, MERRA-2, DWD}},
  pages        = {{1141 -- 1147}},
  title        = {{{Comparison and Validation of Irradiance Data: Satellite Meteorological Dataset MERRA-2 vs. Meteonorm and German Weather Service (DWD)}}},
  doi          = {{10.4229/EUPVSEC20212021-5BV.4.11}},
  year         = {{2021}},
}

@inproceedings{16899,
  abstract     = {{To compare efficiency and yield of many micro-inverters available on the world market in 2014-2020, an in- and outdoor test laboratory at the University of Paderborn has been set up. The inverters have been fed by identical and calibrated crystalline silicon PV modules of 215 Wp. To monitor accurately DC input, AC power output and energy yield, each of the micro-inverters has been equipped with a calibrated electricity meter. For micro-inverters requiring control units for grid-feeding that has been acquired also. The comparison covers efficiency-load characteristics as well as electrical energy yields. Purchase costs vary considerably between the models in comparison, sometimes inverter costs are higher than module costs, particularly if an additional grid-connection or interface device is needed for operation. The weighted conversion efficiency according to EU and CEC standards has been measured and calculated. While some inverters have been optimized for high irradiance levels, they ranked better at the CEC efficiency, others performed very well also for low irradiance levels, thus ranking higher at in the EU-efficiency tables. These results are deviating from the actual energy yield measurements, which show a slightly different ranking. At one inverter, an accurate, but very slow MPPT algorithm that barely could follow quickly changing irradiance levels could be the reason for this effect. Another inverter switched off after operation at high power output for a while. Apparently, some inverters are been optimized to show excellent EU and CEC efficiency ratings. Two of the inverters featuring two inputs did not show an exceptional performance at the EU- and CEC-ratings, but they achieved top ranks at the AC energy yield for the first years. For the customer, the AC yield is a major performance indicator of any microinverter and should be included in the datasheet.}},
  author       = {{Krauter, Stefan and Bendfeld, Jörg}},
  booktitle    = {{Proceedings of the 47th IEEE Photovoltaic Specialists Conference (PVSC 47) JUNE 15 - AUGUST 21, 2020 VIRTUAL MEETING}},
  issn         = {{ 0160-8371}},
  keywords     = {{yield, AC, micro-inverter, MPPT, CEC rating, EU efficiency, Photovoltaic, Solar}},
  location     = {{VIRTUAL MEETING}},
  pages        = {{1429--1432}},
  publisher    = {{IEEE}},
  title        = {{{Comparison of Microinverters: Update on Rankings of Conversion Efficiencies and Energy Yields}}},
  doi          = {{10.1109/PVSC45281.2020.9300953}},
  year         = {{2020}},
}