title: Botswana electricity sector planning and CO₂ emissions reduction through solar PV in office buildings

authors: Mukwaso, Simasiku Titus

abstract: Coal is the most abundant energy resource in Botswana, with a total reserve of about 212 billion tones. Currently 600 MW of electricity is generated from coal and 160 MW is generated from imported diesel fuel. With rising electricity demand in the future it is planned that the extra generation will come from coal, however there is mounting pressure to reduce CO₂ emissions during electricity generation. The main challenge Botswana is facing, from an electricity generation point of view, is to find alternate and economic clean energy technologies for electricity generation in order to reduce CO₂ emissions. With little natural renewable energy resources other than the sun, the most obvious alternative to coal generation is solar generation. Botswana is blessed with about 21MJ/m² /day of average solar radiation with over 3200 hours of sunshine per year.

In order to reduce emissions Botswana has set targets of 15 percent and 25 percent electricity generation from renewables (most likely solar) by 2025 and 2030 respectively, as well as replacing planned coal generation expansion with Coal Bed Methane (CBM) in future. Furthermore, the government is also considering using Carbon Capture Storage (CCS) to reducing CO₂ emissions from coal generation, as an alternative to widespread solar.

With these thoughts in mind this study investigates; (1) generation options for reducing CO₂ emission in the electricity sector of Botswana through to 2030, (2) the economic feasibility of using solar PV in Botswana office buildings, and (3) the amount of CO₂ emissions reduction that can be achieved if the solar PV generation was rolled out to many office buildings in Botswana, both commercial and government buildings.

From the electricity sector planning study compared to business as usual, a 44.6 percent CO₂ emission reduction in Botswana is possible through uptake of 25 percent solar PV and replacing diesel with CBM. With additional application of CCS to coal, emissions can be reduced further to 82.1 percent. However, the additional 37.5 percent emissions reduction relies heavily on CCS a developing technology with high system costs.

From the solar PV study, two DC solar PV systems were determined to be the most economical system with Net Present Costs (NPC) of US$ 1,840,105.75 and US$ 473,394.53, compared to two AC solar PV systems with NPC of US$ 2,068,279.31 and US$ 587,673.24. The levelized costs for DC solar PV system without inverter and batteries is 0.47 US$/kWh which is 14.9% less than the AC solar PV system with inverter without batteries at 0.54 US$/kWh. Similarly, the DC solar PV system with batteries is 1.82 US$/kWh, 3.8% lower as compared to levelized costs for AC solar PV system with batteries and inverter at 1.89 US$/kWh.

Lastly, it is estimated that between 12 percent and 39 percent CO₂ emissions reduction is possible in Botswana by rolling out installation of DC solar PV systems in 11564 commercial and government office buildings throughout Botswana.

text: Botswana electricity sector planning and CO₂ emissions reduction through solar PV in office buildings Coal is the most abundant energy resource in Botswana, with a total reserve of about 212 billion tones. Currently 600 MW of electricity is generated from coal and 160 MW is generated from imported diesel fuel. With rising electricity demand in the future it is planned that the extra generation will come from coal, however there is mounting pressure to reduce CO₂ emissions during electricity generation. The main challenge Botswana is facing, from an electricity generation point of view, is to find alternate and economic clean energy technologies for electricity generation in order to reduce CO₂ emissions. With little natural renewable energy resources other than the sun, the most obvious alternative to coal generation is solar generation. Botswana is blessed with about 21MJ/m² /day of average solar radiation with over 3200 hours of sunshine per year.

In order to reduce emissions Botswana has set targets of 15 percent and 25 percent electricity generation from renewables (most likely solar) by 2025 and 2030 respectively, as well as replacing planned coal generation expansion with Coal Bed Methane (CBM) in future. Furthermore, the government is also considering using Carbon Capture Storage (CCS) to reducing CO₂ emissions from coal generation, as an alternative to widespread solar.

With these thoughts in mind this study investigates; (1) generation options for reducing CO₂ emission in the electricity sector of Botswana through to 2030, (2) the economic feasibility of using solar PV in Botswana office buildings, and (3) the amount of CO₂ emissions reduction that can be achieved if the solar PV generation was rolled out to many office buildings in Botswana, both commercial and government buildings.

From the electricity sector planning study compared to business as usual, a 44.6 percent CO₂ emission reduction in Botswana is possible through uptake of 25 percent solar PV and replacing diesel with CBM. With additional application of CCS to coal, emissions can be reduced further to 82.1 percent. However, the additional 37.5 percent emissions reduction relies heavily on CCS a developing technology with high system costs.

From the solar PV study, two DC solar PV systems were determined to be the most economical system with Net Present Costs (NPC) of US$ 1,840,105.75 and US$ 473,394.53, compared to two AC solar PV systems with NPC of US$ 2,068,279.31 and US$ 587,673.24. The levelized costs for DC solar PV system without inverter and batteries is 0.47 US$/kWh which is 14.9% less than the AC solar PV system with inverter without batteries at 0.54 US$/kWh. Similarly, the DC solar PV system with batteries is 1.82 US$/kWh, 3.8% lower as compared to levelized costs for AC solar PV system with batteries and inverter at 1.89 US$/kWh.

Lastly, it is estimated that between 12 percent and 39 percent CO₂ emissions reduction is possible in Botswana by rolling out installation of DC solar PV systems in 11564 commercial and government office buildings throughout Botswana.

year: 2017

title: Applying graphic design terms to image tagging

authors: Laing, Simon John

subjects: computer science

abstract: This paper describes key findings from research into the application of graphic design terms to the task of tagging images for later retrieval. The research was motivated by the needs of creative industries in interacting with large image collections, with particular emphasis given to the need for retrieval of imagery using loosely defined visual properties rather than exact match queries based on image subject or similarity. A set of terms chosen from design literature are presented and discussed together with experimental results from testing carried out on students and practitioners of graphic design. Ultimately the tested terms are found to be relatively well understood, though they do not appear to support a high degree of precision.

text: Applying graphic design terms to image tagging This paper describes key findings from research into the application of graphic design terms to the task of tagging images for later retrieval. The research was motivated by the needs of creative industries in interacting with large image collections, with particular emphasis given to the need for retrieval of imagery using loosely defined visual properties rather than exact match queries based on image subject or similarity. A set of terms chosen from design literature are presented and discussed together with experimental results from testing carried out on students and practitioners of graphic design. Ultimately the tested terms are found to be relatively well understood, though they do not appear to support a high degree of precision.

year: 2008

title: Street health: Practitioner service provision for Māori homeless people in Auckland

authors: Nikora, Linda Waimarie

abstract: Homelessness is more than a transient crisis. While access to housing might solve the needs of some, research has shown that the needs of homeless people are much more complex and more a symptom of systematic structural inequalities than an unanticipated emergency (Hopper, 1998). As in other countries, the homeless population in New Zealand is made up of a diverse population of men, women and intersex groups of various ages, sexualities and ethnic backgrounds. Māori are over-represented among this population due to ongoing processes of colonisation and socioeconomic exclusion (Groot et al., 2011). When compared with domiciled citizens, homeless people are more likely to experience a raft of illnesses and unmet health needs, violence, a sense of insecurity, exclusion and fear, and are more likely to commit sui- cide (Hodgetts et al., 2007). Homeless people often experience diverse ill- nesses including asthma, heart disease, diabetes, hepatitis, renal disease, dermatological conditions, malnutrition, oral disease, depression, schizo- phrenia, substance misuse and broken bones (Ellison-Loschmann & Pearce, 2006; Joly et al., 2011; Moore et al., 2007).

text: Street health: Practitioner service provision for Māori homeless people in Auckland Homelessness is more than a transient crisis. While access to housing might solve the needs of some, research has shown that the needs of homeless people are much more complex and more a symptom of systematic structural inequalities than an unanticipated emergency (Hopper, 1998). As in other countries, the homeless population in New Zealand is made up of a diverse population of men, women and intersex groups of various ages, sexualities and ethnic backgrounds. Māori are over-represented among this population due to ongoing processes of colonisation and socioeconomic exclusion (Groot et al., 2011). When compared with domiciled citizens, homeless people are more likely to experience a raft of illnesses and unmet health needs, violence, a sense of insecurity, exclusion and fear, and are more likely to commit sui- cide (Hodgetts et al., 2007). Homeless people often experience diverse ill- nesses including asthma, heart disease, diabetes, hepatitis, renal disease, dermatological conditions, malnutrition, oral disease, depression, schizo- phrenia, substance misuse and broken bones (Ellison-Loschmann & Pearce, 2006; Joly et al., 2011; Moore et al., 2007).

year: 2016