MOBILE FACTORY DESIGN FOR ON-SITE WIND TURBINE TOWER PRODUCTION

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: SMALL BUSINESS GRANT
• Reporting Frequency: Annual
• Accession No.: 1002999
• Grant No.: 2014-33610-21948
• Cumulative Award Amt.: $99,998.00
• Proposal No.: 2014-00085
• Project Start Date: Jun 1, 2014
• Project End Date: Jan 31, 2015
• Grant Year: 2014
• Program Code: [8.6]- Rural & Community Development

Recipient Organization
KEYSTONE TOWER SYSTEMS, INC.
28 DANE ST
SOMERVILLE,MA 02143

Performing Department
(N/A)

Non Technical Summary
Larger, taller wind turbines could significantly reduce the cost of wind energy and enable much broader deployment. For example, a recent study from the National Renewable Energy Lab [NREL/TP-5000-61063] showed that increasing tower heights from 96m to 140m would nearly double the available wind resource in the US (adding 1,800 GW) and bring wind development to many areas where it is not currently feasible. However, traditional tower designs cannot cost-effectively scale up due to the size constraints associated with road and rail transportation. Even today towers are on the edge of what can be transported, even with specialty trucks, expensive escorts and significant structural sub-optimization. Keystone Tower Systems has developed an advanced manufacturing process that solves this problem by enabling on-site tower production. With Keystone's system, which adapts the well-understood process of spiral welding to tower construction, transport limits are eliminated and tall, low-cost towers are made possible.Keystone has proven the economics of the tower-spiral-welding system, and has built a scale prototype to demonstrate the fundamental spiral welding technology. However, fully understanding and optimizing the on-site manufacturing process is also necessary to ensure that the system fills the needs of cost-effective wind energy production. In this project, Keystone will work closely with wind industry logistics experts and wind developers on a mobile fabrication facility that can be deployed at the wind farm. The project focuses on key aspects of on-site operation, such as tower coating selection and deployment logistics. Once completed, the results will be used as a basis for a full on-site facility design. With on-site tower production, turbines will be able to reach the strong winds at high hub-heights, reducing the cost of energy and increasing the area available for economic wind deployment. In addition, on-site production is inherently local, bringing jobs to the communities where the wind farm is installed.

Animal Health Component

20%

Research Effort Categories

Basic

(N/A)

Applied

20%

Developmental

80%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
402	5310	2020	100%

Knowledge Area
402 - Engineering Systems and Equipment;

Subject Of Investigation
5310 - Machinery and equipment;

Field Of Science
2020 - Engineering;

Keywords

advanced manufacturing

energy

on-site fabrication

spiral welding

wind turbine tower

Goals / Objectives
The goal of this project is to lay the groundwork for full, detailed design of an on-site, wind tower production facility. This facility will be integrated into the wind farm during development, and produce low-cost, tall wind towers at the site, enabling reduced costs for wind energy.Specific objectives of the Phase I project focus on key issues that will be addressed before the full design phase:Site selection: With our partner wind farm developer, select a real potential plant location that is representative of regions where on-site towers will provide high value. This site will serve as the basis for other analyses in this project.Permitting and Logistics: Survey requirements for deployment of on-site facility, including permitting, equipment availability, stock delivery, etc.Foundation predesign: Towers produced on-site can have a much larger base diameter than shipped-in towers, allowing the foundation weight to be reduced. Also, while traditional towers have a door in the tower itself, building the door into the foundation may offer advantages in production rate and overall cost. Keystone will study door options and select one configuration, and produce (in partnership with K2M) a preliminary design for an optimized foundation.Coating selection: Several tower coatings are possible, with trade-offs in cost, curing time, paint booth requirements, etc. With consultation from experts, Keystone will select a coating technology to be used in on-site tower production.Facility development: Create preliminary design for the on-site facility, including total foot-print, secondary operations, labor requirements, etc.Production study: Estimate the production rate of the on-site tower production facility.Assessing impact: Complete system accounting for costs of the on-site facility, and assess the effect of this cost on total tower cost and cost of wind energy.

Project Methods
The tasks in this Phase I project are focused on key questions that should be answered before full, detailed design of an on-site facility is completed. Each requires its own methods that are area-specific. However, each task has some methods in common: consult with one (or more) of Keystone's partners who have expertise and a stake in the area (i.e., a wind turbine OEM will be consulted when tower coatings are being selected); identify and evaluate options, including technical performance and cost; and evaluate effects of each option on the overall system. For example, when selecting a coating for the tower, we will: identify the options (e.g., traditional coatings, epoxy-based coatings); evaluate each candidate in the parameters of interested, (e.g., cost, application method, cure time and temperature, environmental concerns); evaluate how each parameter affects the performance and cost of the tower-production process and consider trade-offs (e.g., faster cure times reduce the size of the facility, lowering cost, but higher material costs may out-balance this effect); consult with industry stake-holders to ensure process approval; and make a final selection.

Progress 06/01/14 to 01/31/15

Outputs
Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Plans for the remainin goals are listed below. Coating selection Speak with industrial coating equipment/material vendors and identify several possible in-field coating solutions. Analyze the cost and time of applying each of these solutions to a reference tower design. Facility development Develop a complete set of operations and segment operations into stations. Detail the workflow of operations in each station and estimate the time, equipment and labor requirements for each task. Production study Based on the operations analysis, estimate the lead time and cycle time of the reference tower design to calculate the tower production rate. Assessing impact Build factory and wind plant cost models to estimate the cost of energy production and the change to local economic impact in terms of cash flow and workforce development.

Impacts
What was accomplished under these goals? Accomplishments for each goal of the project are listed below. Site selection Major activities completed / experiments conducted: - Selected 2 potential example wind farms, one in Ohio and one in Maine -K2M conducted wind resource analysis for each site to compare energy capture at different hub heights 2) Data collected: -Wind resource data 3) Summary statistics and discussion of results: -140m tower can capture 30-50% more energy 4) Key outcomes or other accomplishments realized -Energy capture statistics will serve as key input for economic analysis Permitting and Logistics 1) Major activities completed / experiments conducted: -Permitting review of several states including Ohio, Maine, Texas and Tennesse 2) Data collected: -VOC limits for US states -Permitting department contacts 3) Summary statistics and discussion of results: N/A 4) Key outcomes or other accomplishments realized -VOC limits for coating operation do not pose a critical limitation Foundation predesign 1) Major activities completed / experiments conducted -Cost analysis for foundation design of tower with varying base diameter 2) Data collected -Cost curve of base diameter vs. foundation construction cost -Cost curve of soil water content vs. foundation construction cost -Cost estimate for door-in-foundation concept 3) Summary statistics and discussion of results: N/A 4) Key outcomes or other accomplishments realized -Current foundation designs and costs are feasible. A more detailed design effort is needed to validate construction cost Coating selection Nothing to report Facility development Nothing to report Production study Nothing to report Assessing impact Nothing to report

Publications

Progress 06/01/14 to 01/31/15

Outputs
Target Audience: For the Phase I project, the target audience includes Keystone's industry partners and other wind industry stakeholders, who will learn about Keystone's system and how it can be incorporated into industry products and processes. For the overall development of on-site spiral welded tower production, the target audiences include: local communities who will benefit from the on-site facility (e.g., employment at the facility, sourcing of materials from nearby providers, etc.) ; and all communities that will benefit from replacing fossil fuel-generated electricity with renewable wind generation. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? The results are being shared directly with key wind turbine manufacturers and wind farm developers as we work to design our towers into their turbines and projects. In addition, we have shared the results at the annual American Institute of Steel Constructionconference, and have been invited to share the results at the annual American Wind Energy Assocciation conference. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Site Selection 1) Major activities completed / experiments conducted: -Selected 2 potential example wind farms, one in Ohio and one in Maine -Worked with the developers of these sites (Iberdrola Renewables and First Wind) to assess the integration into these sites -K2M conducted wind resource analysis for each site to compare energy capture at different hub heights 2) Data collected: -Annual average wind resource and energy data 3) Summary statistics and discussion of results: A 140m tower can capture around 30% more energy than the standard, transportable 80m towers. (the specific reference sites yielded 36.4% and 25.2% higher energy capture) 4) Key outcomes or other accomplishments realized The wind energy capture statistics will serve as key input for economic analysis. Permitting and Logistics 1) Major activities completed / experiments conducted: Permitting review of several states including Ohio, Maine, Texas and Tennessee 2) Data collected: -VOC limits for US states -Permitting department contacts 3) Summary statistics and discussion of results: N/A 4) Key outcomes or other accomplishments realized It was found that VOC limits for the tower coating operation do not pose a critical limitation Foundation predesign 1) Major activities completed / experiments conducted Cost analysis for foundation design of tower with varying base diameter 2) Data collected -Cost curve of base diameter vs. foundation construction cost -Cost curve of soil water content vs. foundation construction cost -Cost estimate for door-in-foundation concept 3) Summary statistics and discussion of results: N/A 4) Key outcomes or other accomplishments realized It was found that current foundation designs and costs are feasible. A more detailed design effort is needed to validate construction cost Coating selection 1) Major activities completed / experiments conducted Keystone worked with paint manufacturers to verify that in-field application of this coating would be compliant with VOC emissions regulations, and is working with a paint booth manufacturer to develop a system to ensure proper containment of overspray and prevent ground contamination. 2) Data collected VOC content for various coatings, coating application rates for manual and automated applicators, cure times for various 2 and 3 part coating systems, costs for equipment and consumables 3) Summary statistics and discussion of results: The corrosion protection system identified by Keystone consists of an exterior application of a zinc-rich epoxy primer with a polyaspartic topcoat, a similar system to what is used for in-field painting of steel bridges. The tower interior would receive a direct-to-metal polyaspartic one-coat system due to the reduced corrosion risk in C2-C3 environments. 4) Key outcomes or other accomplishments realized The identified coating system enables faster cure times over a broader range of temperatures and humidity than the three-coat epoxy system typically used on towers. This coating system selection was validated by coating suppliers as appropriate for in-field application for wind turbine towers. Facility development 1) Major activities completed / experiments conducted A detailed accounting was performed for all manufacturing operations required for commercial tower production following the initial spiral welding process. These operations were refined into an work-flow order and segmented into 6 distinct work stations; Spiral Welding, Flange Installation, Door Installation, Blasting and Surface Preparation, Painting, and Internals Installation. 2) Data collected For each work station, a detailed bill of resources and bill of materials was compiled, composed of the required equipment, area, materials and labor skill to complete the work operations. This also included equipment setup and breakdown time and labor to account for the factory deployment. 3) Summary statistics and discussion of results: The entire mobile operation requires two acres of land, a relatively small area compared with the overall wind farm, sets up in 3 weeks and costs approximately $1.1M to deploy at the project. The factory capital expense is approximately $15M and requires2 alternating crews of 48 workers to operate. 4) Key outcomes or other accomplishments realized The savings that can be achieved through in-field tower fabrication can save well over $100k per tower, so in-field tower fabrication is justified for projects with more than 10 towers. In the US 98% of wind turbines are installed on projects that are larger than this size. Production study 1) Major activities completed / experiments conducted - A reference 137m tower design was drafted for a Vestas V126 3.3 MW turbine in colaboration with Vestas' tower engineering team -The manufacaturing operations, equipment, and materials needed to produce this tower were identified 2) Data collected Compiled set of equipmentand consumablesfor each operation 3) Summary statistics and discussion of results: The reference tower can be manufactured with less than 48 hour cycle time 4) Key outcomes or other accomplishments realized Keystone can accomplish the current industry standard of delivering and installing a tower every 1-2 days during wind farm construction Assessing impact 1) Major activities completed / experiments conducted Constructed energy production and economic models to perform wind farm cost of energy analysis for Blue Creek wind farm in Ohio 2) Data collected - Original wind farm development and construction plans for Blue Creek -Industry average wind plant component and balance of plant construction costs 3) Summary statistics and discussion of results: The Blue Creek project would produce 16% more energy annually at 15% lower cost if it were built using a 137m on-site Keystone tower instead of a 100m transportable tower with the V126 3.3MW turbine. The difference is even greater if the industry standard 80m towers are assumed. 4) Key outcomes or other accomplishments realized On-site manufacturing of towers would increase the amount of full-time jobs from wind plant construction by 44%. By enabling tall towers, on-site manufacturing increases energy capture and increases cash flow to the local communities by 27%. Across the US, tall towers can double the amount of land area available for economic wind development.

Publications