BY ARNOLD LETSHOLO
Botswana, just like the whole world has compiled its report for submission to the United Nations Framework Convention on Climate Change when countries meet for the 24th conference (COP 24) in Katowice, Poland in a few weeks.
Under its mitigation measures, Botswana highlights that though solar geysers have been in existence for over 50 years in the country, the absorption rate is extremely low.
“According to household survey only 0.14 percent of the households were using solar for heating by 2011 while BPC estimated that only three percent of the high income household are using solar geysers. Using a figure of 0.14 percent, it is estimated that 750 households use solar energy for heating. This translates into 0.07 Gg of CO2 emissions reduction which is projected to increase to 8 Gg of CO2 emissions reduction by 2030. . Figure 11 depicts projected households with solar geysers by 2030,”explains the report.
Assuming that conventional electric geysers are switched for three hours per day with a capacity of 300 watts, one geyser consumes approximately 328.5 kWh per year. Therefore, one solar geyser has the potential to reduce approximately 0.00011 Gg of CO2 emissions, which is approximately 110 kg of CO2 eq. while the cost of one unit is approximately P20 000.00.
The report indicates that another mitigating measure is methane capture and usage as energy source.
“This is a mitigation project that is currently being undertaken at Glen Valley wastewater treatment where methane is captured and flared to heat up oxidation ponds. Methane as an energy gas can be captured and used for generating, electricity, for heating up the ponds to speed up anaerobic processes or as cooking gas. Capturing methane reduces GHG emissions by 53 Gg of CO2 eq. and projected to increase to 400 Gg of CO2 eq. by 2030,” states the report.
There is a significantly large scale proposed biogas project in Lobatse; which will involve establishing and operating a biogas plant and gas upgrading plant which will generate methane from effluent disposed into an open pond water treatment plant and cow dung collected from Botswana Meat Commission and feedlots. It is envisaged that the gas will be used to generate electricity for the national grid system and for cooking gas to replace Liquid Petroleum Gas (LPG). The plant capacity is estimated at 2.5-3 MW and constructed at a cost of BWP 100 million.
Another biogas project is the Mmamashia Biogas Project; with a capacity of approximately 1 MW. The electricity will be generated from agro-waste (chicken and cattle manure) and municipal waste. The proposed plant will be constructed at an estimated cost of BWP 250 million.
Mabesekwa Biogas plant is another biogas plant that is a CDM project that is proposed as both a climate change mitigation action and also to increase the country’s main objective of increasing renewable energy in the energy mix. The project will involve construction and operation of a 200 m3 biogas plant which will provide cooking gas for 400 students on daily basis and a gas-generator to supply 100 households and power 20 streetlights in the village. It is envisaged that success of the biogas plant will be replicated to 3 villages at a rate of one village per year for 4 years. Similar to other biogas projects, the emissions reduction will be two-ways. Firstly, capture of produced CH4 in the atmosphere and secondly, avoided emissions from the use of paraffin and fuel wood as a source of energy.
Furthermore, there are household biogases plants which are mini biogas plants with an average capacity of 6 m3 that are operated at the household level to generate methane for cooking, heating and lighting. This is one of the most feasible, economic and cost-effective climate mitigation options for the country, particularly at the rural population. The initial planning target is to construct 1500 household biogas plants and expand them into future. The cost of construction and installation of the biogas plant including biogas stove is estimated at approximately BWP 15 000.00
Estimating the emissions reduction of the household biogas plants was based on fuel wood consumption displacement at the household level. According to FOSA study, fuel wood per capita in the country is 0.58 tons year. Assuming a household size of four as per population census, fuel wood consumption in the country is estimated at 25-50 kg per day per household. Therefore, this figure was used to estimate emission reductions from the household biogas plants.
Another measure is the efficient lighting introduced initiative that was implemented through BPC aimed at improving electricity saving by giving households CFL bulbs for free and replacing the incandescent light bulbs. It is estimated that CFL save up to 60 percent of electricity relative to the incandescent light bulbs. This mitigation action was implemented in 2012 and it contributed to GHG emissions reduction of about 145 Gg CO2 eq. in 2012 and projected to achieve 300 Gg CO2 eq. by 2030.
Farmers in the country are also voluntarily switching from diesel powered pumps to solar powered borehole influenced mainly by their cost-effectiveness. Similar to other solar appliances, solar powered boreholes replace use of fossil fuel and petroleum products and thus reduce GHG emissions. Currently, it is estimate that there are about 537 solar power boreholes with emission reduction potential of 0.55 Gg CO2 eq. and projected to increase to 169 Gg of CO2 eq. by 2030.