Assignment no.: Document no.: 1 Version: 1 Review of the Amaila Falls Hydropower Project in Guyana | Final Report
GENERATION SYSTEM EXPANSION Least Cost Expansion The recommendable approach for planning hydropower development is to perform a least cost development study of promising sites at a comparable level of investigation and study. The outcome of the study will be a ranking of the project options by criteria including specific generation cost, production profile and reliability, environmental/ social sustainability and perception of construction risks. From the ranking the order of implementation will be decided. A number of studies have been carried out through the years in Guyana of various potential sites for hydropower development, although a broad least cost development study comparing and ranking the alternatives at similar cost and study bases, is yet to be done. Guyana's Power Generation System Expansion Study (Brugman SAS June 2016), which includes several types of power plant, presents four projects of similar size as candidates for the first major hydropower project. These include Amaila Falls (162 MW), Kamaria (152 MW), Kumarau (149 MW) and Tumatumari (152 MW). Amaila Falls and Kumarau are high head projects with modestly sized reservoirs. Kamaria and Tumatumari are low head projects causing inundation of larger areas. Further investigations and studies are required for the three other alternatives to bring them to a stage of preparation comparable with AFHP. The Brugman report underlines the need for updating of the earlier studies (from 30-40 years back) for creating a reliable basis for comparison. Over the last decades development agencies and international development banks have reinforced their standards for environmental and social studies as condition for financial support.
Reasons for Retaining Amaila Falls The Brugman SAS' report does not show any of the three other alternatives convincingly more favourable than Amaila Falls. It presents Kumarau with a specific generation cost about 50% higher than AFHP and a plant factor of 60-65% compared to 70-75% for AFHP. Tumatumari is shown with a marginally lower levelized generation cost than Amaila Falls. The plant factor for Tumatumari, however, is given as 55-60% against 70-75% for AFHP. Consequently, Tumatumari would need higher back-up capacity than AFHP for covering the power deficit in low flow periods. This makes it less suitable for fulfilling the ambition of emission free power generation by 2025. Tumatumari has a much larger inundated area than AFHP, which would give larger scale environmental impacts and require time consuming environmental studies. Kamaria is presented with specific generation cost marginally higher than for AFHP and with a plant factor 65-70% compared to 70-75% for AFHP. The studies for Kamaria Falls dating back to the 1970ties will apparently need thorough upgrading for providing a reliable basis for comparison with AFHP. To our judgement developing "Owner's Technical Requirements" for any of the three other alternatives will take 1-2 years more than updating the same for Amaila Falls. Although certain design aspects of AFHP should be reviewed and revised, we regard the soundness of AFHP as evident and in order to follow up the intentions of the LCDS as fast as possible, we recommend the preparations for AFHP to be resumed.
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