TY - CONF
AU - Kakande, Josephine Nakato
AU - Philipo, Godiana Hagile
AU - Krauter, Stefan
ID - 34156
T2 - Proceedings of the 8th World Conference on Photovoltaik Energy Conversion
TI - Optimal Design of a Semi Grid-Connected PV System for a Site in Lwak, Kenya Using HOMER
ER -
TY - JOUR
AB - 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.
AU - Philipo, Godiana Hagile
AU - Kakande, Josephine Nakato
AU - Krauter, Stefan
ID - 32403
IS - 14
JF - Energies
KW - Energy (miscellaneous)
KW - Energy Engineering and Power Technology
KW - Renewable Energy
KW - Sustainability and the Environment
KW - Electrical and Electronic Engineering
KW - Control and Optimization
KW - Engineering (miscellaneous)
KW - Building and Construction
SN - 1996-1073
TI - Neural Network-Based Demand-Side Management in a Stand-Alone Solar PV-Battery Microgrid Using Load-Shifting and Peak-Clipping
VL - 15
ER -
TY - JOUR
AB - 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.
AU - Philipo, Godiana Hagile
AU - Kakande, Josephine Nakato
AU - Krauter, Stefan
ID - 47961
IS - 14
JF - Energies
KW - Energy (miscellaneous)
KW - Energy Engineering and Power Technology
KW - Renewable Energy
KW - Sustainability and the Environment
KW - Electrical and Electronic Engineering
KW - Control and Optimization
KW - Engineering (miscellaneous)
KW - Building and Construction
SN - 1996-1073
TI - Neural Network-Based Demand-Side Management in a Stand-Alone Solar PV-Battery Microgrid Using Load-Shifting and Peak-Clipping
VL - 15
ER -
TY - CONF
AU - Krauter, Stefan
AU - Khatibi, Arash
ID - 22217
SN - 978-3-948176-14-3
T2 - Tagungsband des 36. PV-Symposium, 18.-26 Mai 2021, online, ISBN 978-3-948176-14-3, S. 301-304.
TI - Einfluss von Steilaufstellung, Nachführung und Einsatz bifazialer PV-Module auf den Speicherbedarf und die Kosten einer 100% EE-Versorgung Deutschlands
ER -
TY - CONF
AB - 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.
AU - Khatibi, Arash
AU - Krauter, Stefan
ID - 24551
KW - Energy potential estimation
KW - Photovoltaic
KW - Solar radiation
KW - Temperature measurement
KW - Satellite data
KW - Meteonorm
KW - MERRA-2
KW - DWD
SN - 3-936338-78-7
T2 - Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition (EUPVSEC 2021)
TI - Comparison and Validation of Irradiance Data: Satellite Meteorological Dataset MERRA-2 vs. Meteonorm and German Weather Service (DWD)
ER -
TY - CONF
AB - 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.
AU - Krauter, Stefan
AU - Bendfeld, Jörg
ID - 24550
KW - AC-modules
KW - Microinverter
KW - Power Conditioning
KW - Efficiency
KW - Yield
KW - PV module size
KW - saturation
KW - performance
SN - 3-936338-78-7
T2 - Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC 2021)
TI - Module-Inverters (Microinverters): Influence of Module Size on Conversion Efficiencies and Energy Yields
ER -
TY - JOUR
AB - 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.
AU - Khatibi, Arash
AU - Krauter, Stefan
ID - 21265
IS - 4
JF - Energies
KW - Solar irradiance
KW - MERRA 2
KW - Meteonorm
KW - DWD
SN - 1996-1073
TI - Validation and Performance of Satellite Meteorological Dataset MERRA-2 for Solar and Wind Applications
VL - 14
ER -
TY - CONF
AB - 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.
AU - Kakande, Josephine Nakato
AU - Philipo, Godiana Hagile
AU - Krauter, Stefan
ID - 24540
KW - Art-D
KW - Afrika
KW - Demand side management
KW - MySQL
KW - Raspberry pi
KW - Data acquisition
SN - 3-936338-78-7
T2 - Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition (EUPVSEC 2021)
TI - Load Data Acquisition in Rural East Africa for the Layout of Microgrids and Demand–Side–Management Measures
ER -
TY - CONF
AU - Krauter, Stefan
AU - Böcker, Joachim
AU - Freitag, Christine
AU - Hehenkamp, Burkhard
AU - Hilleringmann, Ulrich
AU - Temmen, Katrin
AU - Klaus, Tobias
AU - Rohrer, Nicolaus
AU - Lehmann, Sven
ID - 22218
KW - Art-D
KW - Afrika
KW - Resilienz
KW - Resilience
KW - Grid stability
KW - robustness
KW - microgrids
SN - 978-3-948176-14-3
T2 - Tagungsband des 36. PV-Symposiums, 18.-26 Mai 2021
TI - Projekt Art-D Grids: Nachhaltige und stabile Microgrids in Afrika - eine Plattform für Forschung und Lehre für die Entwicklung
ER -
TY - CONF
AB - 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.
AU - Krauter, Stefan
AU - Bendfeld, Jörg
ID - 18390
SN - 3-936338-73-6
T2 - Proceedings of the EUPVSEC 2020
TI - Micro-Inverters: An Update of Comparison of Conversion Efficiencies and Energy Yields
ER -