78 research outputs found

    The Sun Rises in the East (of Africa): A Comparison of the Development and Status of the Solar Energy Markets in Kenya and Tanzania

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    This paper describes, compares and analyses the historical development and current status of Kenya's and Tanzania's emerging solar energy markets. The analysis is based on an extensive literature survey and 25 in-depth personal interviews with experts on the East African solar power market. Kenya's solar market is found to be one of the world's leading markets for off-grid solar uses, with a current installed capacity of over 10 MWp and more than 320,000 solar home systems. Having developed much later than the Kenyan market, Tanzania's market still remains smaller than its neighbour's, with an installed capacity of around 4 MWp and at least 40,000 solar home systems, but is in the process of catching up. In addition to solar home systems, other applications of solar energy technologies, such as in social institutions, telecoms and tourism, are covered. Major differences and similarities between the Kenyan and Tanzanian solar markets are identified and reasons for these are analysed. Initial policy i implications regarding the regulation and promotion of solar energy in East Africa suggest that awareness, availability and affordability are major drivers that all need to be present to enable the widespread uptake of off-grid solar technologies in emerging markets.Solar energy, Photovoltaic energy, Market development, East Africa, Kenya, Tanzania

    WACC the Dog: The Effect of Financing Costs on the Levelized Cost of Solar PV Power

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    The photovoltaic (PV) power industry has grown rapidly in recent years, and associated with that growh has been a decline in costs. There are indications that PV has already reached cost-parity with power off the grid in some markets and projections that it will attain such grid parity in many more markets over the coming decade. Analysts have suggested that the growth in PV has come at an unnecessariy high price, with unnecessarily high subsidies. However, the factors influencing the cost of PV, and the subsidies required to sustain its construction, include more than just the strength of the sun. While differences in costs of such factors as initial capital spending, operation and maintenance, and decommissioning are hard to ascertain, it is possible to account for the cost of capital, on a counry-by-country basis. In this paper, we therefore map the cost of solar PV globally, accountng for both the quality of the solar resource and the cost of capital in order to differentiate levelized cost of electricity (LCOE) from PV. Our results suggest that northern countries may not be an unwise location to subsidize PV construction, and further suggest that efforts to expand PV installation in developing countries may benefit greatly from policies designed to make low cost finance more widely avaiable

    Review of solar PV policies, interventions and diffusion in East Africa

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    Previous research on the diffusion of solar PV in Africa has mainly focused on solar home systems (SHS) in individual countries and thus overlooked developments in other PV market segments that have recently emerged. In contrast this paper adopts a regional perspective by reviewing developments in supportive policies, donor programs and diffusion status in all PV market segments in Kenya, Tanzania and Uganda, as well as identifying the key factors put forward in the literature to explain differences in the diffusion of SHS in these three countries. The paper finds two emerging trends: (i) a movement from donor and government-based support to market-driven diffusion of solar PV; and (ii) a transition from small-scale, off-grid systems towards mini-grids and large-scale, grid-connected solar power plants. The paper points out three generic factors that have contributed to encouraging SHS diffusion in all three countries: (i) the decline in world market prices for PV modules; (ii) the prolonged support from international donors; and (iii) conducive framework conditions provided by national governments. The paper also identifies five key factors that have been elaborated in the literature to explain the higher level of SHS diffusion in Kenya compared to Tanzania and Uganda: (i) a growing middle-class; (ii) geographical conditions; (iii) local sub-component suppliers; (iv) local champions; and (v) business culture. Finally, the paper discusses the lack of attention in the literature given to analysing the amount, nature and timing of donor and government support across countries, processes of learning and upgrading in local PV industries and the interaction between the different explanatory factors

    Serratia marcescens internalization and replication in human bladder epithelial cells

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    BACKGROUND: Serratia marcescens, a frequent agent of catheterization-associated bacteriuria, strongly adheres to human bladder epithelial cells in culture. The epithelium normally provides a barrier between lumal organisms and the interstitium; the tight adhesion of bacteria to the epithelial cells can lead to internalization and subsequent lysis. However, internalisation was not shown yet for S. marcescens strains. METHODS: Elektronmicroscopy and the common gentamycin protection assay was used to assess intracellular bacteria. Via site directed mutagenesis, an hemolytic negative isogenic Serratia strain was generated to point out the importance of hemolysin production. RESULTS: We identified an important bacterial factor mediating the internalization of S. marcescens, and lysis of epithelial cells, as the secreted cytolysin ShlA. Microtubule filaments and actin filaments were shown to be involved in internalization. However, cytolysis of eukaryotic cells by ShlA was an interfering factor, and therefore hemolytic-negative mutants were used in subsequent experiments. Isogenic hemolysin-negative mutant strains were still adhesive, but were no longer cytotoxic, did not disrupt the cell culture monolayer, and were no longer internalized by HEp-2 and RT112 bladder epithelial cells under the conditions used for the wild-type strain. After wild-type S. marcescens became intracellular, the infected epithelial cells were lysed by extended vacuolation induced by ShlA. In late stages of vacuolation, highly motile S. marcescens cells were observed in the vacuoles. S. marcescens was also able to replicate in cultured HEp-2 cells, and replication was not dependent on hemolysin production. CONCLUSION: The results reported here showed that the pore-forming toxin ShlA triggers microtubule-dependent invasion and is the main factor inducing lysis of the epithelial cells to release the bacteria, and therefore plays a major role in the development of S. marcescens infections

    Are we there yet? Improving solar PV economics and power planning in developing countries: The case of Kenya

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    Despite the rapid decline in the cost of solar photovoltaic (PV) systems in the past five years, even recent academic research suggests that the cost of generating PV electricity remains too high for PV to make a meaningful contribution to the generation of grid electricity in developing countries. This assessment is reflected in the views of policymakers throughout Africa, who often consider PV as a technology suited only to remote locations and small-scale applications. This paper therefore analyzes whether, in contrast to conventional wisdom, PV is already competitive with other generation technologies. Analytically, the paper is based on a levelized cost of electricity (LCOE) model to calculate the cost of PV electricity in Kenya, which serves as a case study. Based on actual technology costs and Kenya's solar resource, the LCOE from PV is estimated at USD 0.21/kWh for the year 2011, with scenario results ranging from USD 0.17.0.30/kWh. This suggests that the LCOE of grid-connected PV systems may already be below that of the most expensive conventional power plants, i.e. medium-speed diesel generators and gas turbines, which account for a large share of Kenya's current power mix. This finding implies that researchers and policymakers may be mistaken in perceiving solar PV as a costly niche technology, rather than a feasible option for the expansion of power generation in developing countries

    WACC the dog: The effect of financing costs on the levelized cost of solar PV power

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    The adoption of solar photovoltaic (PV) technologies has expanded rapidly in recent years, leading to suggestions that this growth, which occurred mostly in high-latitude countries with often low levels of sunshine, may have come at an unnecessarily high price. However, the factors influencing the cost of solar PV, and the subsidies required to sustain its uptake, include more than just the level of sunshine. While cross-country differences in technology costs are hard to ascertain, it is possible to account for the cost of capital on a country-by-country basis. In this paper, we therefore map the cost of solar PV globally, accounting for differences in both the solar resource and the financing cost in order to calculate the levelized cost of electricity (LCOE) from solar PV systems in 143 countries. In contrast to the work of other researchers who typically treat financing costs as uniform across countries, our results suggest that the LCOE of solar PV systems in northern countries may in fact be lower than in equatorial countries, and high latitude countries may thus not have been an unwise location to subsidize the adoption of solar PV technologies in the past. Our results further suggest that efforts to expand PV installation in equatorial developing countries may benefit greatly from policies designed to make low cost finance more widely available, which underlines on-going efforts to "de-risk" low carbon investments

    In vitro activation of the Serratia marcescens hemolysin through modification and complementation.

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    The hemolytic activity of Serratia marcescens is determined by two polypeptides, termed ShlA and ShlB. ShlA is synthesized as an inactive precursor (ShlA*) and secreted with the help of ShlB, which is located in the outer membrane. In this study, it is shown that a cell lysate containing ShlB as well as partially purified ShlB converted ShlA* to the active ShlA hemolysin. ShlA remained active after removal of ShlB by column chromatography. In contrast to the stable modification of ShlA* by ShlB, a reversible activation was achieved by adding to ShlA* an N-terminal fragment of ShlA (ShlA16), consisting of 269 amino acid residues of ShlA and 18 residues of the vector. The nonhemolytic ShlA16 complemented ShlA* only when it was synthesized in an ShlB-producing cell. A deletion derivative of ShlA*, lacking residues 4 to 117, was complemented by ShlA16 but not activated by ShlB. Activation of ShlA* by ShlB at 4 degrees C proceeded at a much slower rate than complementation by ShlA16. It is concluded that ShlA* is modified by ShlB. ShlA16 modified by ShlB complements the missing modification of ShlA* in trans. Modification by ShlB occurs in the N-terminal part of ShlA*, which is also the reaction in vivo which results in active ShlA hemolysin in the culture supernatant. The HpmA hemolysin of Proteus mirabilis, which is very similar to ShlA, was also activated in vitro by ShlB and complemented by ShlA16
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