Faculty of Engineering
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Publication Open Access Passive techniques for residential buildings in low altitudes of Sri Lanka(Institution of engineers: Colombo, 1999) Jayasinghe, M.T.R; Attalage, R. AThe role of passive techniques, which utilises a certain number of passive elements to maintain the thermal comfort within the built environments of residential buildings at low atlitudes of Sri Lanka, has been highlighted. The possibility of defining a unique neutral temperature of 26°C for low altitutes of Sri Lanka has been utilised in a rational way in presenting simplified set of rules of thumb, that can be used by the designers at early stages. The effects of orientation, shading devices, window sizes, roofing materials, insulation, colour of the exterior and interior walls, use of courtyards to maximise natural ventilation, and arrangement of roof to minimise structural cooling are shown with suitable examples.Publication Embargo Economy wide emission impacts of carbon and energy tax in electricity supply industry: A case study on Sri Lanka(Pergamon, 2007-07-01) Siriwardena, K; Wijayatunga, P. D.C; Fernando, W.J.L.S; Shrestha, R. M; Attalage, R. AThis paper presents the results and analysis of a study conducted with the objective of investigating the impact on economy wide emissions due to carbon and energy taxes levied within the electricity generation sector of Sri Lanka. This exercise is mainly based on the input–output table developed by the national planning department. An input–output decomposition technique is used to analyze four types of effects that contribute to the overall reduction in equivalent carbon, NOx and SO2 emissions. These four effects are: fuel mix effect (i.e. the change in emissions due to variation I fuel mix), structural effect (i.e. change in emissions due to changes in technological coefficients with taxes compared to that without taxes), final demand effect (i.e. the change in emissions associated with changes in final demand) and joint effect (i.e. the interactive effect between or among the fuel mix, structural and final demand effects). The polluting fuel sources and low energy efficiency generation technologies are less preferred under these tax regimes. Of the four effects, a change in fuel mix in thermal electricity generation and a change final demand for electricity were found to be the main contributors in achieving economy wide emission reductions. It was found in the analysis that a minimum of US$ 50/tC tax or US$ 1.0/MBtu of energy tax is required to have a significant impact on economy wide emissions in the Sri Lankan context. This translates into an overall increase in electricity generation cost of approximately USCts 0.9 kW−1 h−1 and USCts 0.6 kW−1 h−1 under the carbon and energy tax regimes, respectively. The reduction in emissions is also strongly coupled with the value of the price elasticity of electricity.Publication Embargo Analysis of rural household energy supplies in Sri Lanka: energy efficiency, fuel switching and barriers to expansion(Pergamon, 2003-05-01) Attalage, R. A; Wijayatunga, Priyantha DCA majority of the households in Sri Lanka, as in the case of many developing countries, is concentrated in the rural areas of the country. Unfortunately, very little attention has been paid until recently to analyse and address various issues associated with rural energy supplies, particularly those issues regarding barriers to penetration of clean and convenient sources of energy. This paper presents the results and analysis of a study conducted through a sample study on domestic energy supplies in rural Sri Lanka with emphasis on cooking and lighting energy requirements. The paper has attempted to highlight policy issues associated with rural energy supplies and possible solutions to them in the context of the country’s overall picture of the energy sector.Publication Embargo Analysis of household cooking energy demand and its environmental impact in Sri Lanka(Pergamon, 2002-11-01) Attalage, R. A; Wijayatunga, Priyantha DCThis paper presents the results and analysis of a study conducted with the objective of investigating the cooking energy requirements in the Sri Lanka domestic sector and the environmental emissions associated with it. The study was conducted out through a sample and showed that the main household energy supply sources were biomass, liquefied petroleum gas (LPG), electricity and kerosene with electricity being used largely for water boiling in all subsectors. It was observed that the urban sector cooking is largely dominated by LPG (95% of urban households) while the rural sector cooking is confined mainly to biomass (95% of rural households). The suburban sector consists of a mixture of all the sources (LPG-70% and biomass-85% of suburban households). Similarly, LPG dominates in electrified households (76.4% of electrified households), while biomass dominates in all non-electrified households. It was found in the analysis that the highest level of gaseous emissions due to cooking activity occurs in the rural areas, mainly due to the relatively large use of biomass, while the lowest level of emissions is recorded in a typical suburban household. Also, the analysis shows that fuel switching in domestic cooking activities from biomass to LPG and kerosene can be used as a measure to reduce emissions due to higher stove efficiencies and lower emission factors associated with these fuels. Substitution of 50% of biomass usage by kerosene in the rural households will result in 39–50% reduction in emissions within the rural sector. Further, substitution of 50% of biomass usage in urban and suburban sectors by LPG results in 4–49% reduction in emissions within these sectors.Publication Embargo Socio-economic impact of solar home systems in rural Sri Lanka: a case-study(Elsevier, 2005-06-01) Attalage, R. A; Wijayatunga, Priyantha DCThe use of solar photovoltaic systems of 25 Wp to 50 Wp (frequently called solar home systems, or SHSs) has been spreading fast in the rural areas of Sri Lanka as a source of energy used for domestic lighting, mainly because of the financial incentives provided by the donor agencies and aggressive marketing strategies of the SHS dealers in rural areas. This paper presents the outcome and the analysis of a study conducted with the objective of investigating the social, economic and environmental impact of SHSs in rural Sri Lanka. The study involved conducting a survey of 125 households having SHSs, in the Uva province of Sri Lanka, through personal visits. It was evident that the households are extremely satisfied with the technology that has replaced their kerosene lamps, which had been providing household lighting requirements. The quality of life, in terms of activities such as longer study hours of children, longer TV watching hours for the family and lessening the risk of fatal kerosene lamp accidents, has improved with the introduction of the SHSs. It is concluded that the large-scale penetration of solar home systems in Sri Lanka has helped rural communities both in terms of improved socio-economic conditions and reduced adverse environmental impacts, contrary to the belief that the financial burden of such systems imposed on the families outweighs the benefits. But when comparing the benefits of SHSs against the extension of the national grid, the country needs to seriously examine its options for the areas currently targeted by SHS dealers.Publication Embargo Strategies to overcome barriers for cleaner generation technologies in small developing power systems: Sri Lanka case study(Pergamon, 2006-06-01) Wijayatunga, Priyantha DC; Siriwardena, Kanchana; Fernando, W J L S; Shrestha, Ram M; Attalage, R. AThe penetration of cleaner and energy efficient technologies in small power systems such as the one in Sri Lanka has encountered many problems. This has caused major concerns among the policy makers, mainly in the context of the growing need to reduce harmful emissions in the electricity supply industry from the point of view of both local environmental pollution as well as the global warming concerns. This paper presents the outcome of a study involved in identifying and ranking the barriers to the promotion of cleaner and energy efficient technologies and strategies to overcome these barriers in Sri Lanka. Barriers for renewable energy based systems such as wind and wood fuel fired plants (dendro thermal power) and cleaner technologies such as liquefied natural gas (LNG) fired combined cycle and IGCC (coal) were identified based on a survey. A direct assessment multi-criteria decision making method called Analytic Hierarchy Process (AHP) was used to rank the barriers. The most effective strategies are proposed to address the three major barriers for each of these technologies based on extensive discussions with all the stakeholders in the electricity industry. It was found that lack of financing instruments, high initial cost and lack of assurance of resource supply or availability are the main barriers for renewable technologies. As for cleaner fuel and technology options associated with conventional generation systems, the lack of a clear government policy, uncertainty of fuel supplies and their prices and the reliability of the technologies themselves are the major barriers. Strategies are identified to overcome the above barriers. Establishment of a proper feed in tariff, geographical diversification of installations and capacity building in commercial banks are suggested for wind power. Investment incentives, streamlining of wood production and research on site identification are proposed for wood fuel fired plants. Also the study suggests delayed implementation, combined planning with other sectors of the economy, incorporating environmental cost in planning and investment incentives as strategies for IGCC and LNG based technologies.Publication Embargo [PDF] from researchgate.net Roof orientation, roofing materials and roof surface colour: their influence on indoor thermal comfort in warm humid climates(Elsevier, 2003-03-01) Jayasinghe, M T R; Attalage, R. A; Jayawardena, A IThe excessive heat transferred through the roof is one of the main causes of thermal discomfort in warm humid climatic conditions, which prevail in the tropical zone. Therefore, the selection of the most appropriate roof orientation and materials will be important for desirable thermal performance of passive houses. This study investigates the effect of the roof orientation, roofing materials, insulation and the surface colour of the roof on the maximum indoor temperature of a house located in a warm humid climatic region. It is shown with the aid of computer simulations that the roof orientation has no significant effect on a properly planned passive house. However, the use of appropriate materials and insulation could afford significant improvement, which could be further enhanced with the use of light colours for the roof surface.Publication Open Access Potential of biomass fuel conservation in selected Asian countries(Pergamon, 1999-07-01) Bhattacharya, S. C; Attalage, R. A; Leon, M Augustus; Amur, G. Q; Salam, P Abdul; Thanawat, CThe potential of savings in the biomass consumed for energy in seven Asian countries—China, India, Pakistan, Nepal, Philippines, Sri Lanka and Vietnam—is estimated, if the centuries-old traditional methods of biomass use are reconsidered and an efficient, rational use is implemented. The present pattern and share of biomass consumption of different traditional biomass energy devices are recorded. The efficiency of traditional technologies and that of improved ones—technologies which are practically applicable or already in use somewhere else—are compared and the potential of biomass savings is calculated. The total biomass saving potential in all seven countries together has been estimated at 322 million tons/yearPublication Open Access Potential of biomass fuel conservation in selected Asian countries(Pergamon, 1999-07-01) Bhattacharya, S. C; Attalage, R. A; Leon, M Augustus; Amur, G. Q; Salam, P Abdul; Thanawat, CThe potential of savings in the biomass consumed for energy in seven Asian countries—China, India, Pakistan, Nepal, Philippines, Sri Lanka and Vietnam—is estimated, if the centuries-old traditional methods of biomass use are reconsidered and an efficient, rational use is implemented. The present pattern and share of biomass consumption of different traditional biomass energy devices are recorded. The efficiency of traditional technologies and that of improved ones—technologies which are practically applicable or already in use somewhere else—are compared and the potential of biomass savings is calculated. The total biomass saving potential in all seven countries together has been estimated at 322 million tons/year