Energy Efficiency of Building Technologies and Climate Change- a Case Study of Carbon Sequestration in Migori County

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University of Nairobi Research Archive
The global population has continued to increase leading to a greater demand for housing and associated building materials and products which affects the environment and climate in various ways. The effects on environment happens at different phases mainly at the extraction and manufacturing phase where energy consumed depends on the building technology adopted. Due to inadequate research, data and literature on the application of the building materials in meeting the housing demand, the energy consumed and equivalent carbon dioxide emitted in entire stages of production by building technology processes are lacking in developing countries with no exception to Kenya. This study estimated how building technologies by using soil, water and forest/tree cover affect carbon sequestration potential of these resources. The study was done in Migori county with the objective of establishing energy expenditure of building technologies and their effects on carbon sequestration processes and hence potential contribution to climate change through atmospheric CO2 accumulation. The study identified the dominant building materials adopted in the county and their embodied energy levels; assessed the extent of adoption of energy efficient building, resource efficiency of mortarless compared to mortared technologies, established the relationship between building materials use and greenhouse gas emissions; and determined suitability of approval processes to promote selected building technologies by Regulatory Authorities. The main hypothesis of the study was that building technologies have no significant effects on carbon sequestration and hence does not contribute to adverse climate change.The study applied survey, experimental and correlation design approach and adopted both quantitative and qualitative sampling methods to generate primary data towards addressing the research objectives. The survey method was essential in obtaining building technologies, embodied energy and the resultant carbon dioxide emission equivalent of the selected building materials. The county of study was identified by way of purposive sampling. Multi-stage sampling was employed with county as a unit of study, sub-counties forming the study first stratum and the nature of wards (urban and rural) as the second stratum unit of study from which the wards were sampled. The study identified the major approved walling materials in the study area to be bricks and concrete with specific embodied energy of 3.0 MJ/kg and 0.670 MJ/Kg respectively. The study further revealed that there is low application of energy efficient technologies such as interlocking stabilized soil blocks, prefabricated and precast materials. The experimental design revealed that the building materials extraction, manufacture, transportation, and construction consume significant amount of energy and emit greenhouse gas into the atmosphere and that the level of emission of greenhouse gas is dependent on the building technologies adopted. The mortared technology was associated with large amount of embodied energy and equivalent greenhouse gas emission which impact negatively on human life due to high social cost of pollution.The study findings were used to show national outlook of embodied energy and equivalent CO2e projections for the years 1800, 2019 and 2050 of the various walling materials. It is demonstrated that less efficient building technologies continues to dominate the housing sector with bricks leading over the period of analysis at 7,176 GJ in 1800, 306,730 GJ in 2019 andxxi590,263 GJ in 2050 if the current environment of Migori is to prevail nationally. The CO2 emission associated with the walling materials shows a direct relationship since bricks attracted higher values of CO2 emission at 22,404 tons in 1800, 575,317 tons in 2019 and 1,104,363 tons in 2050. Similarly, energy efficient building technologies such as ISSB attracted low greenhouse gas emission. The study concludes that there is a strong relationship between the applied building technology and building materials and climate change demonstrating the need to minimize the embodied energy by using energy efficient building technology and adopting the use of walling materials with minimized embodied energy in order to reduce the greenhouse gas emission. The study revealed that there was minimal knowledge on the application of energy efficient technologies and that the approval process does not promote the use of energy efficient building materials and technologies due to lack of policy to spearhead the initiative.This study is significant in the policy formulation related to the energy efficiency building codes, green building regulations, implementing sustainable environmental strategies and action plans. It is also essential in providing professional knowledge on the causal relationship between building technologies, building material, climate change, environmental sustainability and environmental degradation in the built environment in regard to carbon sequestration relating to soil, water and tree/forest cover