This paper presents the optimal mapping of hybrid energy systems, which are based on wind and PV, with the consideration of energy storage and backup diesel generator, for households in six locations in the South South geopolitical (SS) zone of Nigeria: Benin-city, Warri, Yenagoa, Port Harcourt, Uyo and Calabar. The optima hybrid energy systems are able to meet 7.23 kWh/day of a household's electrical energy. The hybrid energy system for each of the locations was optimally chosen based on HOMER software computation and TOPSIS multi-criteria decision-making algorithm that considers technical, economic, environmental, and sociocultural criteria. Wind energy potential was conducted for the six locations using the Weibull distribution function; the wind speed ranges between 3.21-4.19 m/s at 10m anemological height. The wind speeds and the wind characteristics were extrapolated for 30 m and 50 m hub heights. The solar resource potential across the six locations is also presentedranges between 4.21-4.71 kWh/m 2 /day. The best hybrid system for the locations in Benin-city, Yenagoa and Port Harcourt is the Diesel generator-PV-Wind-Battery system; whereas the best hybrid system for the locations in Warri, Uyo and Calabar is the PV-Wind-Battery system. The hybrid systems in Benin-city, Yenagoa and Port Harcourt emit CO 2 ; only 8.47%, 15.02% and 14.09% of the business as usual (the diesel generator). The payback time ranges between 3.7-5.4 years, using the business as usual cost of energy of 0.893 US$/kWh; whereas the cost of energy of the hybrid systems ranges between 0.459-0.562 US$/kWh, which compares well with available literature in the public domain. The design parameters of the optima hybrid energy systems are also presented. The methodology presented here will serve as a design tool for renewable energy professionals.

No abstract

This paper presents the design analysis of a photovoltaic (PV) system to power the CAD/CAM Laboratory at the Department of Mechanical Engineering, University of Port Harcourt. Life cycle cost and break-even point analyses are also carried out to assess the economic viability of the system. The unit cost of electricity for the designed PV system is high compared to the current unit cost of the municipally supplied electricity, but will be competitive with lowering cost of PV system components and favourable government policies on renewable energy. The approach and data provided are useful for designing solar systems in the area. The automated MS Excel spreadsheet developed could be used for the design and economic analyses of PV system in any other geographical region once the input data are sorted. Since about 90% of businesses in Nigeria currently own diesel generators, it is expected that future work should be devoted to the optimum combination of PV-Battery-Diesel system in electricity generation for optimum economic benefits to the country. Keywords: photovoltaic system design, renewable energy technology, solar energy economics

No abstract

The coastline rural communities in the Niger Delta region of Nigeria have long suffered from the consequences of poor rural electrification, environmental degradation, and health challenges. There is an urgent need to provide an optimal sustainable and environment-friendly energy system for the coastline rural communities in Nigeria, which has the potential of ameliorating the climate change in this country. The HOMER hybrid optimization software and the estimated domestic energy demand of the coastline rural communities were used to determine the best PV solar energy system. The NASA SEE database with monthly averaged values for global horizontal radiation over a 22-year period was considered in the current analysis. The daily energy demand of a typical household in the communities was estimated for the existing energy demand (EED), future electric energy demand (FEED), and future base energy demand (FBED) scenarios as 5.640, 8.830, and 7.233 kWh, respectively. The suggested best energy system has a cost of electricity of 0.651, 0.653, and 0.674 $/kWh for the EED, FEED, and FBED, respectively. The best energy system gives the best components with an appropriate operating strategy to provide an efficient, reliable, cost-effective, and environment-friendly system. It is shown that both positive energy policies of the Federal Government of Nigeria toward renewable energy penetration and the support from the oil-producing companies toward their operational areas would see the cost of electricity being significantly reduced. It is envisaged that the implementation of the suggested energy system with other environmentally responsible interventions would support the Niger-Delta's coastline rural communities, whose livelihoods have been impaired by gas and oil exploration, to attain their full environmental and socioeconomic potentials. ARTICLE HISTORY

Oko C.O.C., Diemuodeke E.O., Akilande I.S., 2010. Design of hoppers using spreadsheet. Res. Agr. Eng., 56: 53-58. This paper presents a spreadsheet add-in for the design of mass flow conical and wedge hoppers. The Jenike's hopper design charts for mass flow were curve fitted. The relationships obtained were used together with other relevant expressions to develop an add-in tool for the determination of the pertinent hopper design parameters (exit size, mass flow rate, semi-included angle, flow factor, and critical applied stress) in the Microsoft Excel environment. The add-in was tested with experimental data, and results obtained were in agreement with those obtained in the literature.

No abstract

No abstract