Estimating Tidal Energy Resource Potential for Power Production Along Kenyan Coast-line

Abstract

Kenyan fast economic progress evident by a population ranked at third highest growth rate in Sub-Saharan Africa as per World Bank 2015 should invest in infrastructure. The industrialization (oil and gas discoveries), transport (standard gauge railway), international grid networks and increased employment opportunities, calls for expansion of electrical energy sources to meet the current and future demand. Unfortunately, the mature fossil fuels energy supplies have caused environmental crisis evident by climate change and climate variability, as a result of global warming due to temperature effects and air pollution. In 2008, Kenya Vision 2030 strong environmental policies and regulations targets were set towards reduction of greenhouse gas emissions and significant renewable energy improvement by driving a low carbon economy. The rapid depletion of fossil fuel reserves and their dire influence on global policy precipitated to inflated energy costs due to disruptive repercussions that affect trade balance and negative emissions effect. The Kenyan reserves status may change with the recent Tullow oil discoveries in March 2016. Diverse energy sources with emphasis on renewable energy investments as per European Commission‟s 2011 Energy strategy roadmap 2050 are essential and urgent to improve security of energy supplies. This advocates for an alternative exploration of safe, reliable, quality, competitive and affordable energy for all consumers. The thesis examined marine tidal stream resource potential for renewable energy generation using computational hydrodynamic models, i.e. Matlab and excel. The assessment entailed resource characteristics, converter device performance and renewable energy yield predicted. The geographical focus was Mombasa, Lamu, supported by published reports on exploitable tidal stream energy resources, and the deployment technology. The thesis presented applied theoretical calculations and numerical simulations to estimate not only the power to be extracted from the flow through a passage, but also reduction in passage flow. The analysis took into account physical and environmental constraints to quantify the untapped tidal stream electrical power potential in Kenya, along the Indian Ocean. viii Kenya‟s effective grid connected electricity capacity currently is at 3000 MW as at March 2015, with a strategic target to increase beyond 5000 MW by 2016. In accordance to the theoretical calculations and simulations, an estimate of 1.9 GW (16.5 TW/h per annum) of tides and tidal power can be extracted averaged across the fortnightly tidal cycle whose resource potential can be higher with deployment. The tidal stream energy resources in Kenya are abundant for electricity extraction with proper site planning and optimization of the ocean energy converters. Characterization, mapping and tapping of the tidal resource reduce uncertainties thus increase and advance investment value of the current green energy initiative. The estimated global potential of tidal stream energy is agreed to exceed 120 GW (1053 TW/h per annum) with negligible investment in Africa and India as per Ocean Energy Europe, 2017. Significant upstream and downstream effects of energy extraction on velocity and elevation in a channel set-up extended to a sigma layer model of the hydrostatic primitive equations. Simulations demonstrated the limits within which the blocking effect of a tidal farm was of significance regarding the change to the hydrodynamic regime brought about by extensive energy extraction and potential redistribution of tidal currents away from the installed device(s) location. Although the assessment outcome points out that Mombasa and Lamu tides and tidal energy resources are viable for exploitation, inherent shortcomings exists on high capital costs, political instability, annual reliable energy density, technology level upgrade and human capacity competence. The current estimated costs are higher than the existing energy systems, a measure which can be addressed to technically contribute strategically in the formulation of necessary policies and networks to realize the overall ocean energy potential and promotion.