Papers by Ahmad AL-Shehri

International Journal of Green Energy, 2010
Recent climatic anomalies such as hot summers, cold winters, hurricanes, and cyclones are all ref... more Recent climatic anomalies such as hot summers, cold winters, hurricanes, and cyclones are all reflections of global warming due to burning of fossil fuels. To combat unprecedented global warming and to mitigate future energy challenges, there is worldwide interest in utilization of renewable sources of energy such as solar-photovoltaic (solar-PV) and wind energy. Other driving forces paving avenue for renewable energy include rapid escalation in oil prices, growing concerns regarding depletion of oil/gas reserves, etc. Retrofitting of diesel systems with hybrid wind-PV-diesel systems is being widely disseminated to reduce diesel fuel consumption and to minimize atmospheric degradation. One of the potential market for deployment of hybrid systems is in remote locations which are driven by diesel generators. The Kingdom of Saudi Arabia (KSA) has a number of remote villages scattered all over the Kingdom. The aim of this study is to analyze wind speed and solar radiation data of Rafha, KSA, and to assess the technical and economic potential of hybrid wind-PV-diesel power systems to meet the load requirements of a typical remote village Rawdhat Bin Habbas (RBH) with annual electrical energy demand of 15,943 MWh. Rafha is located near RBH. The monthly average wind speeds range from 2.99 m/s to 4.84 m/s at 10 m height. The monthly average daily global solar radiation ranges from 3.04 to 7.3 kWh/sq.m. The hybrid systems simulated consist of different combinations of 600 kW wind machines, PV panels, supplemented by diesel generators. National Renewable Energy Laboratory's (NREL) Hybrid Optimization Model for Electric Renewables (HOMER) software has been used to perform the techno-economic study. The simulation results indicate that for a hybrid system comprising of 1.2 MW wind farm capacity (two 600 kW units, 50 m hub-height) and 1.2 MW of PV capacity together with 4.5 MW diesel system (three 1.5 MW units), the renewable energy fraction with 0% annual capacity shortage is 24% (10% wind + 14% PV). The cost of generating energy (COE) from this hybrid wind-PV-diesel system has been found to be 0.118 $/kWh (“assuming diesel fuel price of 0.1$/l”). The study exhibits that for a given hybrid configuration, the number of operational hours of diesel generators decreases with increase in wind farm and PV capacity. Attention has also been focused on wind/PV penetration, unmet load, excess electricity generation, percentage of fuel savings and reduction in carbon emissions (relative to diesel-only situation) of different hybrid systems, cost breakdown of wind-PV-diesel systems, COE of different hybrid systems, etc.
Wind Engineering, 2004
ABSTRACT In the present study, hourly mean wind-speed data recorded at Rafha, Saudi Arabia, have ... more ABSTRACT In the present study, hourly mean wind-speed data recorded at Rafha, Saudi Arabia, have been analyzed for the potential of utilising autonomous hybrid (wind-diesel) power systems to meet the load requirements of a typical remote settlement, namely Rawdhat ...

International Journal of Sustainable Energy, 2007
Since the maturing of the wind farm industry, attention has been focused on the use of wind turbi... more Since the maturing of the wind farm industry, attention has been focused on the use of wind turbines for electricity production in remote areas. Generally, remote villages are driven by diesel generators. However, introduction/dissemination of wind energy conversion systems (WECS) into the existing diesel systems results in the reduction of the diesel fuel consumption and eventually allows atmospheric pollution to subside. A short-term energy storage integrated with wind-diesel system may compensate for fluctuations in the power output of the wind turbine and raise the fuel saving potential. The Kingdom of Saudi Arabia's (K.S.A) area is large, with large number of villages/settlements scattered all over the Kingdom. In the present study, hourly mean wind-speed data recorded at an airport, K.S.A., has been analyzed to investigate the technical and economic feasibility/viability of utilizing off-grid hybrid (wind-diesel-battery) power systems to meet the load requirements of a typical remote/isolated village with annual electrical energy demand of 13,244 MWh. The airport is located in the vicinity of the candidate settlement. The hybrid systems simulated comprise of various combinations (wind farms) of 600 kW commercial WECS supplemented with diesel generators and a short-term battery storage. The amount of battery storage capacity has been varied from 0 to 60 load minutes (equivalent to 0–60 min of average load). National Renewable Energy Laboratory's (NREL’s) HOMER software has been used to perform the technical and economic analysis of hybrid wind-diesel-battery power systems. The investigation indicates that for a hybrid system consisting of 3.6 MW (six 600 kW wind machines, 50 m hub-height) wind farm capacity together with 4.5 MW diesel system (three 1.5 MW diesel units) and a battery storage of 30 load minutes (equivalent to 30 min of average load), the wind penetration is 24%. The cost of generating energy from the above hybrid configuration has been found to be 0.078 US$/kWh (assuming a diesel fuel price of 0.1 $/liter). The simulation results highlight that the number of operational hours of diesel generators in wind-diesel system decreases with increase in wind farm capacity. The study also illustrates that for a given hybrid wind-diesel system, the decrease in diesel run time is further enhanced by inclusion of battery storage capacity. An attempt has been made to address the effect of wind penetration, effect of hub-height on energy production, cost of wind-diesel-battery systems, cost of energy production, excess electricity, un-met load, percentage fuel savings and decrease in carbon emissions, etc (for different scenarios such as wind-diesel without storage, wind-diesel with storage, as compared to diesel-only situation).

International Journal of Green Energy, 2010
Recent climatic anomalies such as hot summers, cold winters, hurricanes, and cyclones are all ref... more Recent climatic anomalies such as hot summers, cold winters, hurricanes, and cyclones are all reflections of global warming due to burning of fossil fuels. To combat unprecedented global warming and to mitigate future energy challenges, there is worldwide interest in utilization of renewable sources of energy such as solar-photovoltaic (solar-PV) and wind energy. Other driving forces paving avenue for renewable energy include rapid escalation in oil prices, growing concerns regarding depletion of oil/gas reserves, etc. Retrofitting of diesel systems with hybrid wind-PV-diesel systems is being widely disseminated to reduce diesel fuel consumption and to minimize atmospheric degradation. One of the potential market for deployment of hybrid systems is in remote locations which are driven by diesel generators. The Kingdom of Saudi Arabia (KSA) has a number of remote villages scattered all over the Kingdom. The aim of this study is to analyze wind speed and solar radiation data of Rafha, KSA, and to assess the technical and economic potential of hybrid wind-PV-diesel power systems to meet the load requirements of a typical remote village Rawdhat Bin Habbas (RBH) with annual electrical energy demand of 15,943 MWh. Rafha is located near RBH. The monthly average wind speeds range from 2.99 m/s to 4.84 m/s at 10 m height. The monthly average daily global solar radiation ranges from 3.04 to 7.3 kWh/sq.m. The hybrid systems simulated consist of different combinations of 600 kW wind machines, PV panels, supplemented by diesel generators. National Renewable Energy Laboratory's (NREL) Hybrid Optimization Model for Electric Renewables (HOMER) software has been used to perform the techno-economic study. The simulation results indicate that for a hybrid system comprising of 1.2 MW wind farm capacity (two 600 kW units, 50 m hub-height) and 1.2 MW of PV capacity together with 4.5 MW diesel system (three 1.5 MW units), the renewable energy fraction with 0% annual capacity shortage is 24% (10% wind + 14% PV). The cost of generating energy (COE) from this hybrid wind-PV-diesel system has been found to be 0.118 $/kWh (“assuming diesel fuel price of 0.1$/l”). The study exhibits that for a given hybrid configuration, the number of operational hours of diesel generators decreases with increase in wind farm and PV capacity. Attention has also been focused on wind/PV penetration, unmet load, excess electricity generation, percentage of fuel savings and reduction in carbon emissions (relative to diesel-only situation) of different hybrid systems, cost breakdown of wind-PV-diesel systems, COE of different hybrid systems, etc.
Wind Engineering, 2004
ABSTRACT In the present study, hourly mean wind-speed data recorded at Rafha, Saudi Arabia, have ... more ABSTRACT In the present study, hourly mean wind-speed data recorded at Rafha, Saudi Arabia, have been analyzed for the potential of utilising autonomous hybrid (wind-diesel) power systems to meet the load requirements of a typical remote settlement, namely Rawdhat ...

International Journal of Sustainable Energy, 2007
Since the maturing of the wind farm industry, attention has been focused on the use of wind turbi... more Since the maturing of the wind farm industry, attention has been focused on the use of wind turbines for electricity production in remote areas. Generally, remote villages are driven by diesel generators. However, introduction/dissemination of wind energy conversion systems (WECS) into the existing diesel systems results in the reduction of the diesel fuel consumption and eventually allows atmospheric pollution to subside. A short-term energy storage integrated with wind-diesel system may compensate for fluctuations in the power output of the wind turbine and raise the fuel saving potential. The Kingdom of Saudi Arabia's (K.S.A) area is large, with large number of villages/settlements scattered all over the Kingdom. In the present study, hourly mean wind-speed data recorded at an airport, K.S.A., has been analyzed to investigate the technical and economic feasibility/viability of utilizing off-grid hybrid (wind-diesel-battery) power systems to meet the load requirements of a typical remote/isolated village with annual electrical energy demand of 13,244 MWh. The airport is located in the vicinity of the candidate settlement. The hybrid systems simulated comprise of various combinations (wind farms) of 600 kW commercial WECS supplemented with diesel generators and a short-term battery storage. The amount of battery storage capacity has been varied from 0 to 60 load minutes (equivalent to 0–60 min of average load). National Renewable Energy Laboratory's (NREL’s) HOMER software has been used to perform the technical and economic analysis of hybrid wind-diesel-battery power systems. The investigation indicates that for a hybrid system consisting of 3.6 MW (six 600 kW wind machines, 50 m hub-height) wind farm capacity together with 4.5 MW diesel system (three 1.5 MW diesel units) and a battery storage of 30 load minutes (equivalent to 30 min of average load), the wind penetration is 24%. The cost of generating energy from the above hybrid configuration has been found to be 0.078 US$/kWh (assuming a diesel fuel price of 0.1 $/liter). The simulation results highlight that the number of operational hours of diesel generators in wind-diesel system decreases with increase in wind farm capacity. The study also illustrates that for a given hybrid wind-diesel system, the decrease in diesel run time is further enhanced by inclusion of battery storage capacity. An attempt has been made to address the effect of wind penetration, effect of hub-height on energy production, cost of wind-diesel-battery systems, cost of energy production, excess electricity, un-met load, percentage fuel savings and decrease in carbon emissions, etc (for different scenarios such as wind-diesel without storage, wind-diesel with storage, as compared to diesel-only situation).
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Papers by Ahmad AL-Shehri