@article{35428,
abstract = {{This paper presents a model of an energy system for a private household extended by a lifetime prognosis. The energy system was designed for fully covering the year-round energy demand of a private household on the basis of electricity generated by a photovoltaic (PV) system, using a hybrid energy storage system consisting of a hydrogen unit and a lithium-ion battery. Hydrogen is produced with a Proton Exchange Membrane (PEM) electrolyser by PV surplus during the summer months and then stored in a hydrogen tank. Mainly during winter, in terms of lack of PV energy, the hydrogen is converted back into electricity and heat by a fuel cell. The model was created in Matlab/Simulink and is based on real input data. Heat demand was also taken into account and is covered by a heat pump. The simulation period is a full year to account for the seasonality of energy production and demand. Due to high initial costs, the longevity of such an energy system is of vital interest. Therefore, this model was extended by a lifetime prediction in order to optimize the dimensioning with the aim of lifetime extension of a hydrogen-based energy system. Lifetime influencing factors were identified on the basis of a literature review and were integrated in the model. An extensive parameter study was performed to evaluate different dimensionings regarding the energy balance and the lifetime of the three components, electrolyser, fuel cell and lithium-ion battery. The results demonstrate the benefits of a holistic modelling approach and enable a design optimization regarding the use of resources, lifetime and self-sufficiency of the system}},
author = {{Möller, Marius Claus and Krauter, Stefan}},
issn = {{2673-9941}},
journal = {{Solar}},
number = {{1}},
pages = {{25--48}},
publisher = {{MDPI AG}},
title = {{{Dimensioning and Lifetime Prediction Model for a Hybrid, Hydrogen-Based Household PV Energy System Using Matlab/Simulink}}},
doi = {{10.3390/solar3010003}},
volume = {{3}},
year = {{2023}},
}
@inproceedings{47118,
author = {{Möller, Marius Claus and Krauter, Stefan}},
booktitle = {{Proceedings of the 40th European Photovoltaik Solar Energy Conference and Exhibition}},
location = {{Lisbon, Portugal}},
title = {{{Evaluation of the Influence of Different Energy Usage Behavior, Component Dimensionings and PV Orientations on the Suitability and Lifetime of a Hybrid, Hydrogen-Based PV Energy System for a Private Household}}},
year = {{2023}},
}
@inproceedings{47119,
author = {{Krauter, Stefan and Bendfeld, Jörg}},
booktitle = {{Proceedings of the 40th European Photovoltaik Solar Energy Conference and Exhibition}},
location = {{Lisbon, Portugal}},
title = {{{PV Microinverters: Latest Efficiency Rankings, Energy Yield Assessments, Firmware Issues}}},
year = {{2023}},
}
@inproceedings{48532,
author = {{Philipo, Godiana Hagile and Kakande, Josephine Nakato and Krauter, Stefan}},
booktitle = {{Proceedings of the 2023 IEEE PES/IAS PowerAfrica Conference}},
location = {{Marrakech, Morocco}},
title = {{{Combined Economic and Emission Dispatch of a Microgrid Considering Multiple Generators}}},
year = {{2023}},
}
@inproceedings{48533,
author = {{Kakande, Josephine Nakato and Philipo, Godiana Hagile and Krauter, Stefan}},
booktitle = {{Proceedings of the 2023 IEEE PES/IAS PowerAfrica Conference}},
location = {{Marrakech, Morocco}},
title = {{{Demand side management potential of refrigeration appliances}}},
year = {{2023}},
}
@inproceedings{48531,
author = {{Philipo, Godiana Hagile and Kakande, Josephine Nakato and Krauter, Stefan}},
booktitle = {{Proceedings of the 2023 IEEE AFRICON, Nairobi, Kenya}},
location = {{ Nairobi, Kenya}},
title = {{{Demand-Side-Management for Optimal dispatch of an Isolated Solar Microgrid}}},
year = {{2023}},
}
@inproceedings{32334,
abstract = {{The market for microinverters is growing, especially in Europe. Driven by the strongly rising prices for electricity, many small photovoltaic energy systems are being installed. Since monitoring for these plants is often quite costly, their yields are often not logged. Since 2014, microinverters have been studied at the University of Paderborn. The investigations are divided into indoor and outdoor tests. In the indoor area conversion efficiencies as a function of load have been measured with high accuracy and ranked according to Euro- and CEC weightings. In the outdoor laboratory, the behavior in the real world is tested. Energy yields have been measured outdoors via identical and calibrated crystalline silicon PV modules. Here, the investigations were carried out with modules of the power of 215 Wp until the year 2020. Because of the increasing module power nowadays, modules with an output of 360 Wp are now being used. To assess the influence of PV module size, two extremes have been investigated: A rather small module with 215 Wp - as it has been used 10 years ago, and a brand-new module (2021) offering 360 Wp. Both types of modules contain 60 solar cells in series connection. Appling the low-power modules, the challenge for the different micro-inverters has been during weak-light conditions, using the high-power modules, some inverters temporarily reach their power limits and yield is reduced. A method using a reference configuration of inverter & module and a linear equation resulting in the actual yield, any module & inverter configuration can be characterized by just the two coefficients.}},
author = {{Krauter, Stefan and Bendfeld, Jörg and Möller, Marius Claus}},
booktitle = {{Proceedings of the 49th IEEE Photovoltaic Specialists Conference}},
location = {{Philadelphia, PA, USA}},
title = {{{Microinverter testing update using high power modules: Efficiency, yield, and conformity to a new ”estimation formula” for variation of PV panel size}}},
year = {{2022}},
}
@inproceedings{32333,
abstract = {{This paper provides a hybrid energy system model created in Matlab/Simulink which is based on photovoltaics as its main energy source. The model includes a hybrid energy storage which consists of a short-term lithium-ion battery and hydrogen as long-term storage to ensure autonomy even during periods of low PV production (e.g., in winter). The sectors heat and electricity are coupled by using the waste-heat generated by production and reconversion of hydrogen through an electrolyser respectively a fuel cell. A heat pump has been considered to cover the residual heat demand (for well insulated homes). Within this paper a model of the space heating system as well as the hot water heating system is presented. The model is designed for the simulation and analysis of a whole year energy flow by using a time series of loads, weather and heat profiles as input. Moreover, results of the energy balance within the energy system by simulation of a complete year by varying the orientation (elevation and azimuth) of the PV system and the component sizing, such as the lithium-ion battery capacity, are presented. It turned out that a high amount of heating energy can be saved by using the waste heat generated by the electrolyser and the fuel cell. The model is well suited for the analysis of the effects of different component dimensionings in a hydrogen-based energy system via the overall energy balance within the residential sector.}},
author = {{Möller, Marius Claus and Krauter, Stefan}},
booktitle = {{Proceedings of the 49th IEEE Photovoltaic Specialists Conference}},
location = {{Philadelphia, PA, USA}},
title = {{{Model of a Self-Sufficient PV Home using a Hybrid Storage System based on Li-Ion Batteries and Hydrogen Storage with Waste Heat Utilization }}},
year = {{2022}},
}
@article{30262,
abstract = {{In this paper, a model of a hybrid, hydrogen-based energy system for a household which includes the heating sector is presended. With such an energy system it's possible to enable energy autarky over a whole year based on solar energy. The scope of this study was to present a verified hybrid energy system model created in Simulink which can be used to prospectively size future similar energy systems where hydrogen in combination with a li-ion battery shall be used as energy storage type.}},
author = {{Möller, Marius Claus and Krauter, Stefan}},
issn = {{1996-1073}},
journal = {{Energies / Special Issue "Sustainable Energy Concepts for Energy Transition"}},
publisher = {{MDPI / Basel, Switzerland}},
title = {{{Hybrid Energy System Model in Matlab/Simulink based on Solar Energy, Lithium-Ion Battery and Hydrogen}}},
doi = {{10.3390/en15062201}},
volume = {{15 (6), 2201}},
year = {{2022}},
}
@inproceedings{34155,
author = {{Krauter, Stefan and Bendfeld, Jörg}},
booktitle = {{Proceedings of the 8th World Conference on Photovoltaik Energy Conversion}},
location = {{Milano / Italy}},
title = {{{Microinverter PV Systems: New Efficiency Rankings and Formula for Energy Yield Assessment for any PV Panel Size at different Microinverter types}}},
year = {{2022}},
}
@inproceedings{34156,
author = {{Kakande, Josephine Nakato and Philipo, Godiana Hagile and Krauter, Stefan}},
booktitle = {{Proceedings of the 8th World Conference on Photovoltaik Energy Conversion}},
location = {{Milano / Italy}},
title = {{{Optimal Design of a Semi Grid-Connected PV System for a Site in Lwak, Kenya Using HOMER}}},
year = {{2022}},
}
@article{32403,
abstract = {{Due to failures or even the absence of an electricity grid, microgrid systems are becoming popular solutions for electrifying African rural communities. However, they are heavily stressed and complex to control due to their intermittency and demand growth. Demand side management (DSM) serves as an option to increase the level of flexibility on the demand side by scheduling users’ consumption patterns profiles in response to supply. This paper proposes a demand-side management strategy based on load shifting and peak clipping. The proposed approach was modelled in a MATLAB/Simulink R2021a environment and was optimized using the artificial neural network (ANN) algorithm. Simulations were carried out to test the model’s efficacy in a stand-alone PV-battery microgrid in East Africa. The proposed algorithm reduces the peak demand, smoothing the load profile to the desired level, and improves the system’s peak to average ratio (PAR). The presence of deferrable loads has been considered to bring more flexible demand-side management. Results promise decreases in peak demand and peak to average ratio of about 31.2% and 7.5% through peak clipping. In addition, load shifting promises more flexibility to customers.}},
author = {{Philipo, Godiana Hagile and Kakande, Josephine Nakato and Krauter, Stefan}},
issn = {{1996-1073}},
journal = {{Energies}},
keywords = {{Energy (miscellaneous), Energy Engineering and Power Technology, Renewable Energy, Sustainability and the Environment, Electrical and Electronic Engineering, Control and Optimization, Engineering (miscellaneous), Building and Construction}},
number = {{14}},
publisher = {{MDPI AG}},
title = {{{Neural Network-Based Demand-Side Management in a Stand-Alone Solar PV-Battery Microgrid Using Load-Shifting and Peak-Clipping}}},
doi = {{10.3390/en15145215}},
volume = {{15}},
year = {{2022}},
}
@article{47961,
abstract = {{Due to failures or even the absence of an electricity grid, microgrid systems are becoming popular solutions for electrifying African rural communities. However, they are heavily stressed and complex to control due to their intermittency and demand growth. Demand side management (DSM) serves as an option to increase the level of flexibility on the demand side by scheduling users’ consumption patterns profiles in response to supply. This paper proposes a demand-side management strategy based on load shifting and peak clipping. The proposed approach was modelled in a MATLAB/Simulink R2021a environment and was optimized using the artificial neural network (ANN) algorithm. Simulations were carried out to test the model’s efficacy in a stand-alone PV-battery microgrid in East Africa. The proposed algorithm reduces the peak demand, smoothing the load profile to the desired level, and improves the system’s peak to average ratio (PAR). The presence of deferrable loads has been considered to bring more flexible demand-side management. Results promise decreases in peak demand and peak to average ratio of about 31.2% and 7.5% through peak clipping. In addition, load shifting promises more flexibility to customers.}},
author = {{Philipo, Godiana Hagile and Kakande, Josephine Nakato and Krauter, Stefan}},
issn = {{1996-1073}},
journal = {{Energies}},
keywords = {{Energy (miscellaneous), Energy Engineering and Power Technology, Renewable Energy, Sustainability and the Environment, Electrical and Electronic Engineering, Control and Optimization, Engineering (miscellaneous), Building and Construction}},
number = {{14}},
publisher = {{MDPI AG}},
title = {{{Neural Network-Based Demand-Side Management in a Stand-Alone Solar PV-Battery Microgrid Using Load-Shifting and Peak-Clipping}}},
doi = {{10.3390/en15145215}},
volume = {{15}},
year = {{2022}},
}
@inproceedings{22217,
author = {{Krauter, Stefan and Khatibi, Arash}},
booktitle = {{Tagungsband des 36. PV-Symposium, 18.-26 Mai 2021, online, ISBN 978-3-948176-14-3, S. 301-304. }},
isbn = {{978-3-948176-14-3}},
location = {{Staffelstein / online}},
pages = {{301--304}},
publisher = {{Conexio}},
title = {{{Einfluss von Steilaufstellung, Nachführung und Einsatz bifazialer PV-Module auf den Speicherbedarf und die Kosten einer 100% EE-Versorgung Deutschlands}}},
year = {{2021}},
}
@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{24550,
abstract = {{Efficiencies and energy yields of microinverters available on the market during 2014‒2021 have been
measured, compared, and ranked. Conversion efficiencies as a function of load have been measured indoors with high
accuracy and ranked according to Euro- and CEC weightings. Energy yields have been measured outdoors via
identical and calibrated crystalline silicon PV modules of 215 Wp (until 2020) and 360 Wp (starting 2021). Inverters
with two inputs have been fed by two of those modules. DC input, AC power output and energy yield of each microinverter have been recorded by individual calibrated electricity meters. CEC and EU efficiency rankings have been
computed and compared. To assess the influence of PV module size, two extremes have been investigated: A rather
small module with 215 Wp - as it has been used 10 years ago, and a brand-new module (2021) offering 360 Wp. Both
types of modules contain 60 solar cells in series connection. Appling the low-power modules, the challenge for the
different micro-inverters has been during weak-light conditions, using the high-power modules, some inverters
temporarily reach their power limits and yield is reduced. A method using a reference configuration of inverter &
module and a linear equation y = ax + b resulting in the actual yield, any module & inverter configuration can be
characterized by just the coefficients a and b.}},
author = {{Krauter, Stefan and Bendfeld, Jörg}},
booktitle = {{Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC 2021)}},
isbn = {{3-936338-78-7}},
keywords = {{AC-modules, Microinverter, Power Conditioning, Efficiency, Yield, PV module size, saturation, performance}},
pages = {{659 -- 663}},
title = {{{Module-Inverters (Microinverters): Influence of Module Size on Conversion Efficiencies and Energy Yields}}},
doi = {{10.4229/EUPVSEC20212021-4CO.3.4}},
year = {{2021}},
}
@article{21265,
abstract = {{Fast-growing energy demand of the world makes the researchers focus on finding new energy sources or optimizing already-developed approaches. For an efficient use of solar and wind energy in an energy system, correct design and sizing of a power system is of high importance and improving or optimizing the process of data obtaining for this purpose leads to higher performance and lower cost per unit of energy. It is essential to have the most precise possible estimation of solar and wind energy potential and other local weather parameters in order to fully feed the demand and avoid extra costs. There are various methods for obtaining local data, such as local measurements, official organizational data, satellite obtained, and reanalysis data. In this paper, the Modern-Era Retrospective analysis for Research and Applications dataset version 2 (MERRA-2) dataset provided by NASA is introduced and its performance is evaluated by comparison to various locally measured datasets offered by meteorological institutions such as Meteonorm and Deutscher Wetterdienst (DWD, or Germany’s National Meteorological Service) around the world. After comparison, correlation coefficients from 0.95 to 0.99 are observed for monthly global horizontal irradiance values. In the case of air temperature, correlation coefficients of 0.99 and for wind speed from 0.81 to 0.99 are observed. High correlation with ground measurements and relatively low errors are confirmed, especially for irradiance and temperature values, that makes MERRA-2 a valuable dataset, considering its world coverage and availability.}},
author = {{Khatibi, Arash and Krauter, Stefan}},
issn = {{1996-1073}},
journal = {{Energies}},
keywords = {{Solar irradiance, MERRA 2, Meteonorm, DWD}},
number = {{4}},
publisher = {{MDPI}},
title = {{{Validation and Performance of Satellite Meteorological Dataset MERRA-2 for Solar and Wind Applications}}},
doi = {{10.3390/en14040882}},
volume = {{14}},
year = {{2021}},
}
@inproceedings{24540,
abstract = {{With its growing population and industrialization, DREs, and solar technologies in particular, provide a
sustainable means of bridging the current energy deficit in Africa, increasing supply reliability and meeting future
demand. Data acquisition and data management systems allow real time monitoring and control of energy systems as
well as performance analysis. However commercial data acquisition systems often have cost implications that are
prohibitive for small PV systems and installations in developing countries.
In this paper, a multi-user, multi-purpose microgrid database system is designed and implemented. MAVOWATT
270 power quality analyzers by GOSSEN METRAWATT, raspberry pi modules and sensors are used for measuring,
recording and storing electrical and meteorological data in East Africa. Socio-economic data is also stored in the
database. The designed system employs open source software and hardware solutions which are best suited to
developing regions like East Africa due to the lower cost implications.
The expected results promise a comprehensive database covering different electro-technical and socio-economic
parameters useful for optimal design of microgrid systems.}},
author = {{Kakande, Josephine Nakato and Philipo, Godiana Hagile and Krauter, Stefan}},
booktitle = {{Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition (EUPVSEC 2021)}},
isbn = {{3-936338-78-7}},
keywords = {{Art-D, Afrika, Demand side management, MySQL, Raspberry pi, Data acquisition}},
pages = {{1505--1510}},
title = {{{Load Data Acquisition in Rural East Africa for the Layout of Microgrids and Demand–Side–Management Measures}}},
doi = {{10.4229/EUPVSEC20212021-6BV.5.38}},
year = {{2021}},
}
@inproceedings{22218,
author = {{Krauter, Stefan and Böcker, Joachim and Freitag, Christine and Hehenkamp, Burkhard and Hilleringmann, Ulrich and Temmen, Katrin and Klaus, Tobias and Rohrer, Nicolaus and Lehmann, Sven}},
booktitle = {{Tagungsband des 36. PV-Symposiums, 18.-26 Mai 2021}},
isbn = {{978-3-948176-14-3}},
keywords = {{Art-D, Afrika, Resilienz, Resilience, Grid stability, robustness, microgrids}},
location = {{Staffelstein / online}},
pages = {{305--309}},
publisher = {{Conexio}},
title = {{{Projekt Art-D Grids: Nachhaltige und stabile Microgrids in Afrika - eine Plattform für Forschung und Lehre für die Entwicklung}}},
year = {{2021}},
}
@inproceedings{18390,
abstract = {{ Efficiencies and energy yields of microinverters available on the market during 2014‒2020 have been
measured, compared, and ranked. Conversion efficiencies as a function of load have been measured indoors with high
accuracy and ranked according to Euro- and CEC weightings. Energy yields have been measured outdoors via
identical and calibrated crystalline silicon PV modules of 215 Wp each. Inverters with two inputs have been fed by
two of those modules. DC input, AC power output and energy yield of each micro-inverter have been recorded by
individual calibrated electricity meters. Apparently, some inverters have been optimized for high irradiance levels
and ranked better at the CEC efficiency ranking, others performed very well also at low irradiance levels, thus
ranking higher at in the EU efficiency ranking. Efficiency ranks are slightly deviating from rankings by energy yield
measurements. At one inverter, a slow MPPT algorithm that barely could follow quickly changing irradiance levels is
most probably responsible for this effect. Another inverter switched off for a while after operation at high power,
another one failed permanently. Apparently, some inverters are been optimized to show excellent datasheet ratings
for EU- or CEC- efficiency. On the other hand, two inverters (each featuring two inputs) did not show an outstanding
performance at the EU- and CEC-ratings but achieved leading ranks for AC energy yields. For the customer, AC
yield is a major performance indicator of a microinverter and should be included in the datasheet.}},
author = {{Krauter, Stefan and Bendfeld, Jörg}},
booktitle = {{Proceedings of the EUPVSEC 2020}},
isbn = {{ 3-936338-73-6}},
location = {{online}},
pages = {{935 -- 938}},
title = {{{Micro-Inverters: An Update of Comparison of Conversion Efficiencies and Energy Yields}}},
doi = {{10.4229/EUPVSEC20202020-4DO.7.2}},
year = {{2020}},
}