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Accounting for the on-site labor cost changes noted above, DNV GL calculated a 3.6% increase in on-site labor costs over off-site. Considering the labor fraction of 30%, the net increase in baseline blade recurring cost is $0.11 per kg. The fundamental price of materials used in the blade are assumed to remain unchanged with on-site manufacturing, however, delivery costs of the materials is assumed to increase due to shipping and handling to maintain the on-site manufacturing process. For conventional off-site manufacturing, some level of supply-chain optimization is typical, such as material sub-suppliers situating manufacturing or chemical processing plants adjacent to blade manufacturing plants to minimize transportation, storage, and delivery costs. DNV GL estimated that supply chain inefficiencies related to adding field delivery of blade materials, chemicals, and process materials would add 15% to the material costs of the blade. Accounting for the material fraction of 35%, the net increase in baseline blade cost is $0.55 per kg. Tool utilization is a manufacturing metric that corresponds to the degree of operating efficiency which the entire manufacturing process achieves. It represents the percentage of time the equipment, facility and process are in production, thus maximizing the distribution of investment costs of the equipment, facility, and process over as much product as possible. Broadly speaking, off-site blade manufacturing facilities are in production about 85% to 95% of the time which effectively distributes tooling, equipment, and facility costs down to 7% of the blade production cost. For on-site manufacturing, all the tooling, molds, process equipment, facility costs, etc. are comparable in magnitude for off-site manufacturing. However, DNV GL estimates that the utilization rate of this equipment would be 50% lower than achieved off-site. Under optimistic scenarios, we assume the on-site factory could produce all the blades for the 150 MW project in a 6-month serial production period. However, we assume a 3-month period is needed to deliver and build the on-site factory. An additional 3-month period is needed to commission the factory, train local workers, and produce a “first article” to demonstrate that all equipment, processes, and workers can meet manufacturing quality and production thresholds. Our 50% reduction in tool utilization (corresponding to a 100% increase in tooling costs) is due to the process equipment, tooling, molds, and facility costs not in serial production for 6 months of the year. Accounting for the tooling utilization fraction of 7%, the net increase in baseline blade cost is $0.73 per kg. DNV GL considers the utilization factor to be optimistic, as it does not explicitly include time for decommissioning of the factory, disassembly of tooling and equipment and preparation for shipment to the next on-site factory location. The combination of these factors result in a 13.3% increase in recurring costs for on-site blade manufacturing over off-site manufacturing, with a resulting $11.84/kg rate.

6.3.2.2 Non-recurring cost adders DNV GL elected to simplify the analysis of non-recurring costs to focus on three of the largest likely contributors: training the local unskilled labor force, factory construction, and “first article” production. DNV GL assumes that these activities are executed with quality and high efficiency, that a quality and engaged workforce is available, and that local landowners and authorities having jurisdiction (AHJs) over approvals support the facility. DNV GL estimated the local unskilled workforce would require ~10 weeks of training and plant commissioning performed by the traveling skilled staff. Given the total headcount of 540 people, a blended hourly rate of $30.10 and 40-hour work weeks, the resulting non-recurring labor cost is $6.5 million. The underlying assumptions for training of local labor force are considered optimistic, and do not explicitly

DNV GL – Document No.: 10080081-HOU-R-01, Issue: C, Status: FINAL www.dnvgl.com

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Supersized wind turbine blade study  

R&D pathways for supersized wind turbine bladesSupersized wind turbine blade studyLawrence Berkeley National LaboratoryDocument Number: 1008...

Supersized wind turbine blade study  

R&D pathways for supersized wind turbine bladesSupersized wind turbine blade studyLawrence Berkeley National LaboratoryDocument Number: 1008...

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