No abstract

Energy supply is a critical indicator for the global United Nations initiatives because of its immense contribution to economic development. In essence, identifying the required energy resource coupled with effective policy strategies is essential to sustainable electricity generation. Nevertheless, future electricity supply requires a range of options that must be robust and workable. Globally, the challenge of harnessing the energy resources sustainably needed for effective electricity generation is alarming. Therefore, the ability to supply a country’s electricity based on the availability and affordability of resources is vital for effective governance. In this study, Ghana’s energy resourcefulness and the profound effects on the future mix of electricity generation are qualitatively reviewed. In particular, the study covers the existing and potential energy resources available for sustainable electricity generation. The study revealed that Ghana mainly uses hydro, natural gas, and solar energy, among others, for electricity generation. Additionally, a framework explores a well-diversified generation mix using nuclear, coal, and more renewable energy sources in the long-term. Key issues that emerged for national consideration include the need for effective policy direction and implementation, appropriate financing concepts, fuel availability, political will, and setting. By far, this review sought to emphasize literature gaps by providing a rich and fertile ground as a template for industry operators, policymakers, and future research direction.

Thermal phenomena such as heat transfer enhancement, heat transfer deterioration, and flow instability observed at supercritical pressures as a result of fluid property variations have the potential to affect the safety of design and operation of Supercritical Water-cooled Reactor SCWR, and also challenge the capabilities of both heat transfer correlations and Computational Fluid Dynamics CFD physical models. These phenomena observed at supercritical pressures need to be thoroughly investigated.An experimental study was carried out by Xi to investigate flow instability in parallel channels at supercritical pressures under different mass flow rates, pressures, and axial power shapes. Experimental data on flow instability at inlet of the heated channels were obtained but no heat transfer data along the axial length was obtained. This numerical study used 3D numerical tool STAR-CCM+ to investigate heat transfer at supercritical pressures along the axial lengths of the parallel channels with water ahead of experimental data. Homogeneous axial power shape HAPS was adopted and the heating powers adopted in this work were below the experimental threshold heating powers obtained for HAPS by Xi. The results show that the Fluid Centre-line Temperature FCLT increased linearly below and above the PCT region, but flattened at the PCT region for all the system parameters considered. The inlet temperature, heating power, pressure, gravity and mass flow rate have effects on WT (wall temperature) values in the NHT (normal heat transfer), EHT (enhanced heat transfer), DHT (deteriorated heat transfer) and recovery from DHT regions. While variation of all other system parameters in the EHT and PCT regions showed no significant difference in the WT and FCLT values respectively, the WT and FCLT values respectively increased with pressure in these regions. For most of the system parameters considered, the FCLT and WT values obtained in the two channels were nearly the same. The numerical study was not quantitatively compared with experimental data along the axial lengths of the parallel channels, but it was observed that the numerical tool STAR-CCM+ adopted was able to capture the trends for NHT, EHT, DHT and recovery from DHT regions. The heating powers used for the various simulations were below the experimentally observed threshold heating powers, but heat transfer deterioration HTD was observed, confirming the previous finding that HTD could occur before the occurrence of unstable behavior at supercritical pressures. For purposes of comparing the results of numerical simulations with experimental data, the heat transfer data on temperature oscillations obtained at the outlet of the heated channels and instability boundary results obtained at the inlet of the heated channels were compared. The numerical results obtained quite well agree with the experimental data. This work calls for provision of experimental data on heat transfer in parallel channels at supercritical pressures for validation of similar numerical studies.

The pursuit of middle-income economic status by Ghana comes with an associated increase in electricity and energy demand. Meanwhile, an increase in either electricity or energy consumption is likely to result in greenhouse gas (GHG) emissions as a result of increasing reliance on fossil fuel consumption. Presently, there is evidence of the impact of climate change on various aspects of Ghana’s socio-economic structures such as energy production, agriculture, and forestry. Therefore, it is imperative to develop and implement a long-term low-carbon sustainable energy supply strategy that will support the electricity demand of the major economic ambitions envisaged. This study applied a quantitative modelling and simulation methodology using the Model for Energy Supply Strategy and their General Environmental Impacts (MESSAGE) analytical tool to analyse the electricity generation system and the impact of fuel options on the environment. It was found that the inclusion of low-carbon emission energy conversion technologies such as renewables and nuclear energy is critical to curtailing carbon dioxide (CO2) emissions in Ghana’s energy sector. Therefore, the incorporation of climate-friendly energy sources into the electricity sector is necessary to achieve sustainable, resilient, and clean electricity generation. Ghana’s fulfilment of its international commitment to climate change depends on reducing its dependence on fossil fuels for electricity generation, thus, exploring the inclusion of zero-emitting sources into the country’s energy mix.

Energy is essential for economic development and improvement of quality of life in every human settlement. Considering her economic aspirations and population growth, Ghana’s energy demand, particularly that of electricity is sure to rise in coming years. Ghana’s total installed electricity generation capacity currently stands at 1810MW, with a current population is estimated to be 24.4 million based on 2010 population census. The country and for that matter is confronted with the challenge of meeting her energy needs in a cost effective and environmentally friendly manner so as to attain middle income status. This policy document presents nuclear power as the most versatile, convenient and competitive source of electrical energy that should be planned for now and will be worth introducing into Ghana’s energy mix for sustainable development of the country.  Nuclear Power Plants can serve as a competitive source of electrical energy for enhancing Ghana’s energy security and socio-economic development for her to attain middle income as purported by political policies.

DOI: http://dx.doi.org/10.5755/j01.erem.60.2.1109

No abstract

SCWR, which is considered as the logical extension of existing LWRs (PWR and BWR), has the potential of increasing the efficiency of power generation to 45% compared to 33% of that of LWRs. But without the challenges of heat transfer and hydrodynamics, and reactor core design materials due to supercritical flow instability which is associated with sharp variation in fluid properties near the vicinity of the pseudo-critical temperature. Supercritical flow instability therefore needs to be addressed ahead of the deployment and operation of SCWR in the near future.

No abstract