Methodological lessons and results from UNEP GHG abatement costing studies. The case of Zimbabwe

This article is based on greenhouse gas emissions and greenhouse gas abatement costing studies carried out for Zimbabwe. The study produced an inventory of GHG emissions for the country and assessed the cost of 17 technological options for reducing GHG emissions on the basis of which was developed a set of abatement cost curves, one based on a discount rate of 6% and another on 10%. The study carried out as part of the UNEP greenhouse gas abatement costing studies shows that GHG emission levels as at 1991 were 16.9 million tonnes having increased from a 1982 level of 8.9 million tonnes. The bulk of these emissions (13.9 million tonnes) were related to the use of coal energy. Abatement costs range from -Z$821.50 (negative costs) per tonne for the cheapest abatement option to Z$31 645.00 for the most expensive option considered. However, omitting the two options at the endpoints of the cost curve the remaining options are in the interval -Z$49.6 to +Z$1673.2. Assessment of these costs was based on cost items such as capital outlay for an option, related fuel costs and a discount rate set at 6% and 10%. Emission reductions of 21% in the short term and 39% compared with baseline in the long term were achieved mainly through energy sector options. A significant range of these were negative cost options mainly associated with end-use efficiency improvements rather than supply side options.