Raphael Niepelt

Dr. Raphael Niepelt


Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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4 March 2022 in International Journal of Hydrogen Energy
Verified
Journal Article
Closed access
FPFlorian Peterssen
Florian Peterssen
MSMarlon Schlemminger
Marlon Schlemminger
CLClemens Lohr
Clemens Lohr
RNRaphael Niepelt
Raphael Niepelt
ABAstrid Bensmann
Astrid Bensmann
RBRolf Brendel
Rolf Brendel

10 November 2015 in Journal of Materials Research
Verified
Journal Article
Closed access
PDF file
RNRaphael Niepelt
Raphael Niepelt
JHJan Hensen
Jan Hensen
VSVerena Steckenreiter
Verena Steckenreiter
RBRolf Brendel
Rolf Brendel
SKSarah Kajari-Schöder
Sarah Kajari-Schöder

8 August 2022 in Renewable Energy
Verified
Journal Article
Closed access
CLC. Lohr
C. Lohr
MSMarlon Schlemminger
Marlon Schlemminger
FPF. Peterssen
F. Peterssen
ABAstrid Bensmann
Astrid Bensmann
RNRaphael Niepelt
Raphael Niepelt
RHRichard Hanke-Rauschenbach
Richard Hanke-Rauschenbach

29 November 2023 in Progress in Photovoltaics: Research and Applications
Verified
Journal Article
Open access
DBDennis Bredemeier
Dennis Bredemeier
CSCarsten Schinke
Carsten Schinke
RNRaphael Niepelt
Raphael Niepelt
RBRolf Brendel
Rolf Brendel
Photovoltaics (PVs) on building facades, either building‐integrated or building‐attached, offer a large energy yield potential especially in densely populated urban areas. Targeting this potential requires the availability of planning tools such as insolation forecasts. However, calculating the PV potential of facade surfaces in an urban environment is challenging. Complex time‐dependent shadowing and light reflections must be considered. In this contribution, we present fast ray tracing calculations for insolation forecasts in large urban environments using clustering of Sun positions into typical days. We use our approach to determine time resolved PV capacity factors for rooftops and facades in a wide variety of environments, which is particularly useful for energy system analyses. The advantage of our approach is that the determined capacity factors for one geographic location can be easily extended to larger geographic regions. In this contribution, we perform calculations in three exemplary environments and extend the results globally. Especially for facade surfaces, we find that there is a pronounced intra‐day and also seasonal distribution of PV potentials that strongly depends on the degree of latitude. The consideration of light reflections in our ray tracing approach causes an increase in calculated full load hours for facade surfaces between 10% and 25% for most geographical locations.

4 July 2023 in Solar RRL
Verified
Journal Article
Open access
RNRaphael Niepelt
Raphael Niepelt
MSMarlon Schlemminger
Marlon Schlemminger
DBDennis Bredemeier
Dennis Bredemeier
FPFlorian Peterssen
Florian Peterssen
CLClemens Lohr
Clemens Lohr
RBRolf Brendel
Rolf Brendel
A fast and extensive build‐up of green hydrogen production is a crucial element for the global energy transition. The availability of low‐cost renewable energy at high operating hours of the electrolyzer is a central criterion in today's choice of location for green hydrogen production. It is analyzed how decreasing electrolyzer costs that are expected by many may influence this choice. The energy system optimization framework ESTRAM is used to find the optimum configuration of wind turbine, photovoltaic (PV), and electrolyzer capacity for covering a given hydrogen demand by locally produced green hydrogen in different European locations. It is found that PV is part of the cost‐optimal solution in 96% of 1372 statistical regions in Europe. Decreasing electrolyzer costs are favoring the utilization of PV in wind–solar hybrid plants. At low electrolyzer costs, pure solar hydrogen outperforms the hybrid variant in many places if hydrogen storage is available, even with few full operating hours per year. At the same time, production costs are converging significantly. The article adds a new perspective to the discussion, as it is systematically shown how further technology development may lead to a shift in locational advantages for green hydrogen production, what should be considered to avoid stranded assets when building infrastructure.

13 April 2021 in Energies
Verified
Journal Article
Open access
PDF file
MSMarlon Schlemminger
Marlon Schlemminger
RNRaphael Niepelt
Raphael Niepelt
RBRolf Brendel
Rolf Brendel
End-use specific residential electricity load profiles are of interest for energy system modelling that requires future load curves or demand-side management. We present a model that is applicable across countries to predict consumption on a regional and national scale, using openly available data. The model uses neural networks (NNs) to correlate measured consumption from one country (United Kingdom) with weather data and daily profiles of a mix of human activity and device specific power profiles. We then use region-specific weather data and time-use surveys as input for the trained NNs to predict unscaled electric load profiles. The total power profile consists of the end-use household load profiles scaled with real consumption. We compare the model’s results with measured and independently simulated profiles of various European countries. The NNs achieve a mean absolute error compared with the average load of 6.5 to 33% for the test set. For Germany, the standard deviation between the simulation, the standard load profile H0, and measurements from the University of Applied Sciences Berlin is 26.5%. Our approach reduces the amount of input data required compared with existing models for modelling region-specific electricity load profiles considering end-uses and seasonality based on weather parameters. Hourly load profiles for 29 European countries based on four historical weather years are distributed under an open license.