The tests showed that in-situ absolute efficiency testing of a small machine, 3500 kW, can berndone within reasonable cost and with good accuracy thus may encourage the industry to performrnsuch tests to a larger extent.rnEfficiency tests were conducted after refurbishment of the hydropower station. Vattenfall PowerrnConsultant performed the tests and the Accusonic method was used for flow measurements onrnthe Kaplan turbine directly coupled to a synchronous generator. Eight (8) paths of ultra-soundrnbeams were used. The same method was used successfully in 1993 on a 750 kW machine withrnFrancis turbine owned by Vasterbergslagens Kraft.rnIt is tempting for suppliers of small hydropower machines to claim higher efficiency than can bernobtained in reality as the cost of verification of a small machine is relatively high. At evaluation ofrnbids, efficiency was evaluated as a major factor based on values derived from prognoses onrnfuture electricity production prices. The tests were performed as to verify the supplier-claimedrnefficiency values of the contract. This was to assure that Vasterbergslagens Kraft is awardingrncontracts only to serious vendors.rnThe total costs for the absolute efficiency test at Ludvika was $ 62 000.rnThe net present value after tax of a 1 % efficiency gain is $ 92 000 and $ 114 000 considering 60rnyears lifetime and interest rates of 8 % and 6 % respectively and thus worthwhile.
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