Windpower Engineering & Development May 2020

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www.windpowerengineering.com

The technical resource for wind profitability

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REAL SOLUTIONS,

REAL SAVINGS!

Rising repair costs and unpredictable turbine downtime are symptoms of a maintenance program that could be more reactive than proactive. HYDAC can help you determine the true costs of system failure and implement a solution to steady maintenance costs and avoid unplanned outages. Our Wind Field Sales and Service Team is ready to meet any and all challenges, from new designs and solutions to upgrades and retrofits.

HYDAC is your one stop solution!

• NF Filter Kit – Can replace an existing non-HYDAC filter housing in a GE 1.X turbine without disturbing the lubrication pump, motor, or hoses. This kit fits through the nacelle hatch without the need of an external crane.

• GW Sensor – Installed in the filter housing for more precise measurement, it sends a signal if the element is experiencing a sudden influx of contaminant.

• MCS Sensor – A plug-and-play sensor, with multiple vibration measurement unit capabilities, allows for the monitoring of metallic contamination to determine if vibration is due to normal environmental variations or a potential gearbox issue.

• Filter Cart OF5HD-HV – Designed to be lifted through the nacelle hatch, this dual filtration unit can be used to remove both water and particulate contamination or for staged particulate contamination removal.

• Split Housing Uptower Cooler (UTC Series) – Eliminates the need for a costly external crane, saving time and money.

• HYROFLEX Cable Clamps – Part of a system of various mounting supports for securing power cables in wind turbines.

Two styles available, half moon and star.

GW Sensor

MCS Sensor

NF Filter Kit

OF5HD-HV Filter Cart

Clamping Solutions

Split Housing Uptower Cooler

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www.HYDAC-NA.com | www.HYDAC.com

HYD1911-2135

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PUBLISHER Courtney Nagle cseel@wtwhmedia.com 440.523.1685 @wtwh_CSeel EDITORIAL

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SUBSCRIBER SERVICES: To order a subscription or change your address, please email: please visit our web site at www.windpowerengineering.com WINDPOWER ENGINEERING & DEVELOPMENT (ISSN 2163-0593) is published four times per year in February, May, September and a special issue in December by WTWH Media, LLC, 1111 Superior Avenue, Suite 2600, Cleveland, OH 44114. Periodicals postage paid at Cleveland, OH and additional mailing offices.

POSTMASTER: Send address changes to: Windpower Engineering & Development, 1111 Superior Avenue, Suite 2600, Cleveland, OH 44114

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WINDPOWER ENGINEERING & DEVELOPMENT

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MAY 2020

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COVER STORY

Bringing fishing and wind communities together to site U.S. offshore wind projects

WINDPOWER ENGINEERING & D E V E LO P M E N T / / V O L . 1 2 N O. 2

Fishermen’s knowledge of the seas can be invaluable, both for maintaining their livelihoods as offshore wind farms are constructed in fishing grounds, and for helping developers make the best decisions for their wind businesses.

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CONTRIBUTORS

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WINDWATCH

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FEATURES 08

Some interesting product and policy news from our website.

On- and off-shore wind project announcements from across the country.

WINDPOWERENGINEERING.COM

See the latest wind power developments and U.S. project news on our website. Also find expert webinars and more from the leading wind power engineering magazine today.

MAY 2020

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An ounce of prevention: When loose bolts bring down a wind project

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Up to 90% of the cost of offshore wind O&M is due to accessibility and logistical challenges.

Through digitalization and a predictive maintenance regime, these costs can be significantly decreased.

WIND WORK AROUND THE UNITED STATES

FIND US ONLINE

The future of predictive analytics in wind farm reliability

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One loose bolt can bring a whole project to a standstill and cost a company thousands. In other applications, loose bolts can pose a significant safety hazard.

www.windpowerengineering.com

How the renewable energy sector will grow despite waning tax credits In the past, companies could sell megawatts at a cheap rate and still make a decent profit because of the PTC. Now, renewable energy companies are finding secure funding without federal assistance.

Eddy current probes add flexibility to wind turbine nondestructive testing

Eddy current technology has long been used in nondestructive testing for wind turbine tower welds, drivetrains and a wide range of spot inspections in O&M programs.

WINDPOWER ENGINEERING & DEVELOPMENT

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WINDPOWER ENGINEERING & DEVELOPMENT

JULIE DESIMONE

NOAH MYRENT

JULIE PEREYRA

HENRY SCHNEIDER

JIMMIE WILLIAMS

JULIE DESIMONE, CPA, is partner at Moss Adams. She is the leader of the firm’s Power, Utilities and Renewable Energy Practice and has been providing auditing, accounting and consulting services for over 20 years. She serves clients in the energy and utility industry, including renewable energy companies.

Some of her specific areas of focus include: industry analysis, advanced utility accounting, contracting, internal control evaluation, litigation support and relationship management.

NOAH MYRENT is the Head of Global Monitoring for ONYX InSight, where he manages a global team that applies advanced signal processing, condition monitoring data analytics and best practices in predictive maintenance in order to routinely monitor thousands of wind turbines every day. From 2013-2015, Noah led the wind energy research team at Vanderbilt University’s Laboratory for Systems Integrity and Reliability. Noah’s background includes structural dynamics, condition monitoring, sensitivity analysis, and rotor blade fault detection. He received his Bachelor’s in acoustical engineering from Purdue University in 2008 and earned his Master’s in mechanical engineering in 2013, also from Purdue.

JULIE PEREYRA is part of the North America sales team for Nord-Lock Group, a Swedish company and a market leader for products that optimize bolted connections. With over 18 years at the

Group, she has significant expertise working with a range of applications and customers on their bolting challenges.

She holds a Bachelor’s in business administration and marketing from Michigan State University, and resides in Fort Lauderdale, Florida.

HENRY SCHNEIDER is the senior communications associate at Stove Boat Communications, where he advises organizations across the U.S. commercial fishing sector, including the Responsible Offshore Development Alliance (RODA).

JIMMIE WILLIAMS is partner at Moss Adams. He has over 25 years of experience assisting middle-market companies, private equity groups and lenders with all aspects of transaction services. His experience includes financial and operational due diligence, outsourced corporate development and M&A support, dispute resolution services, lender services, restructuring services and consulting services related to debt and equity transactions. He has deep experience in all sectors of the energy industry.

BILL ZIEGENHAGEN is a nuclear engineer and former U.S. Navy officer who has spent 13 years as an eddy current product manager at Zetec, which produces non-destructive testing instruments, probes and software for power generation, oil and gas, aerospace and other industries. He is based in Snoqualmie, Washington.

BILL ZIEGENHAGEN

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www.windpowerengineering.com

MAY 2020

wind windWatch Watch Report estimates up to 30 GW of U.S. offshore wind by 2030 A report titled “U.S. Offshore Wind Power Economic Impact Assessment� anticipates between 20 and 30 GW of total offshore wind development along the East Coast by 2030. Offshore wind development on this scale could create 83,000 jobs, $57 billion in investments and $25 billion in annual economic output, the report estimates.

States like New Jersey are already calling for offshore wind project proposals in the gigawatt or higher range.

Gov. Phil Murphy requested 1.2 GW of offshore wind project proposals by September 2020 and set a state goal of 7.5 GW by 2035.

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AWEA releases poll reporting major bipartisan support for offshore wind MAY 2020

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According to a poll conducted by Public Opinion Strategies and released by American Wind Energy Association, more than 80% of U.S. voters on both sides of the political aisle favor offshore wind. The survey results state that both Democrat and Republican voters would prefer the development of wind over the increased use of non-renewable energy sources.

WINDPOWER ENGINEERING & DEVELOPMENT

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WIND WATCH

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North American wind tech safety training doubles in 2019

CLEANPOWER 2020 Conference & Exhibition is cancelled The CLEANPOWER 2020 Conference & Exhibition has been canceled due to ongoing COVID-19 “legal impediments,” travel restrictions and physical distancing recommendations. The conference was originally scheduled to take place June 1-4 in Denver. AWEA is offering educational and networking opportunities online throughout the spring. The next CLEANPOWER conference is slated for June 7-10, 2021, in Indianapolis.

25 GW of U.S. wind projects at risk due to coronavirus

The number of Global Wind Organisation’s basic safety and technical skills courses completed in 2019 doubled in North America. Trainer hubs present in key states like Texas, Oklahoma, Iowa and Wisconsin brought the number of courses completed from 3,920 in 2018 to 8,003 in 2019. The GWO’s technical training aims to create a standard of safety among its member companies and their employees.

The American Wind Energy Association estimates that 25 GW of U.S. wind projects could be at risk of not being completed.

The U.S. wind industry currently holds close to 120,000 jobs, and disruptions from COVID-19 could jeopardize 35,000 jobs, $43 billion in investments and payments to rural communities that rely on that tax base.

Wind power is the country’s largest renewable energy provider Developers brought 9.1 GW of new wind power online in 2019, representing 39% of new utilityscale power additions, and making wind the largest renewable energy provider in the United States. Wind provided more than 7% of the nation’s electricity in 2019, with a total operating capacity of 105 GW, according to the newly released “Wind Powers America Annual Report 2019.” The wind industry currently employs 120,000 people.

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MAY 2020

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Southern Power’s 100-MW Wildhorse Mountain Wind Facility, located in Pushmataha County Oklahoma, began operations in February 2020. Wildhorse Mountain’s generated power is being sold under a 20-year PPA as renewable energy credits through Arkansas Electric Cooperative Corporation. Vestas will provide long-term maintenance for the 29-turbine wind facility.

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Ørsted completes final phase of 338-MW Texas wind project

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EDP Renewables finishes 300-MW Los Mirasoles II Wind Farm

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Ørsted finished construction on the 120-MW final portion of Sage Draw Wind, a wind project built in Garza and Lynn Counties in Texas this April. The 338-MW wind farm can power 120,000 homes and brings Ørsted’s total onshore wind capacity 1.3 GW. The company wants to reach 5 GW of onshore by 2025.

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EDP Renewables put the final touches on a 50-MW addition to the already 250-MW Los Mirasoles II Wind Farm in Texas. The 300-MW wind farm is located in Hidalgo and Starr Counties on land leased from local farmers and landowners. To date, EDPR operates 700 MW of wind energy projects in Texas.

MAY 2020

Dominion Energy hires int’l consultants for 2,600-MW offshore project

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RWE’s 151-MW Peyton Creek Wind Farm begins commercial operations

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205-MW Bright Stalk Wind Farm comes online in Illinois

Construction on EDP Renewables’ 205-MW Bright Stalk Wind Farm was completed at the end of 2019 in McLean County, Illinois. The $300 million wind project will contribute $2.6 million in local taxes annually for county schools, roads and other public services. Bright Stalk’s majority energy offtake is going to Walmart (123 MW) and Salesforce (80 MW).

Dominion Energy contracted Ramboll, a Denmark-based global engineering consulting company, to act as owner’s engineer on the proposed 2,600-MW Coastal Virginia Offshore Wind Project.

Ramboll has worked in offshore wind for 15 years and will assist Dominion with wind farm layouts and yield assessments on the project.

RWE completed and turned on Peyton Creek Wind Farm, a 151-MW and 48-turbine wind farm in Matagorda County, Texas.

Project construction managed to continue through 23 in. of rainfall brought on by Tropical Storm Imelda in September 2019. Peyton Creek will serve the ERCOT customer base, and RWE is currently building two more wind farms in the state.

Avangrid Renewables’ 307MW wind farm is powering Nike facilities

Avangrid Renewables completed the 307.06-MW Karankawa Wind Farm in Texas, which will supply electricity to utility Austin Energy and sports apparel brand Nike. Karankawa Wind Farm was constructed across 18,000 acres in San Patricio and Bee Counties in Texas.

image Credit: Ørsted

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Southern Power completes 100-MW Wildhorse Mountain Wind Facility

560-MW interstate wind portfolio completed in New Mexico and Texas

The fourth and final Broadview wind project was completed in early 2020 after a total of five years of construction for the portfolio. With systems in Curry County, New Mexico, and Deaf Smith County, Texas, the 560-MW wind portfolio has individual ownership from BayWa r.e./Goldman Sachs and Pattern Energy.

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The

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change: The future of predictive analytics in wind farm reliability

BY NOAH MYRENT GLOBAL HEAD OF MONITORING ONYX INSIGHT

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WINDPOWER ENGINEERING & DEVELOPMENT

www.windpowerengineering.com

MAY 2020

Renewable

energy is on the rise, now more than ever. Thanks to advances in digitization and data analytics, wind turbines can be relied on as a robust source of energy. While in the past, wind turbines were largely unintelligent monoliths monitored periodically via on-site technician checks, wind farms are now creating vast oceans of data filled with potential.

The two traditional operations and maintenance (O&M) models for wind farms have been reactive and preventative maintenance. Reactive maintenance involves a “run to failure” model, replacing components when they are degraded to the point of causing problems with the day-today operations of the wind turbines affected.

Preventative maintenance relies on regularly scheduled replacements and repairs. It can be hard to deliver significant savings with this model because of the recurring, scheduled component costs in addition to the resources used for conducting the routine up-tower work. Laboratory results from oil analysis conducted in this manner, for example, can take a significant amount of time from the initial sample collection to having results in-hand, negating many potential benefits of monitoring in the first place. This cumbersome process means that O&M teams do not have the opportunity to proactively manage the performance of their wind turbines and thus minimize potential damage to each turbine’s components.

Up to 90% of the cost of offshore wind O&M is due to accessibility, reflecting the logistical challenges of transporting engineers and technicians to offshore sites. Through digitalization and a predictive maintenance regime, these costs

MAY 2020

can be significantly decreased by making turbine health information available remotely and ensuring that visits by engineers and technicians can be utilized more effectively to replace or repair multiple components at the same time — and reduce the frequency of these visits accordingly.

As it grows, the wind industry must collectively ensure that the levelized cost of energy (LCOE) stays competitive with alternative means of energy generation. This is especially important in light of the move to a merchant market in recent years, shifting financial risk from governments to energy producers.

Despite the subsidies enjoyed by conventional energy around the world, well-executed digitalization of wind energy assets can bring the LCOE below subsidized levels.

O&M teams have an opportunity to lead offshore wind forward and adopt the latest technologies to help maximize efficiencies across the assets they manage. O&M costs make up 60% of all operational expenditure (OPEX) on wind farms — and nearly two-thirds of this expenditure is unplanned. By combining real world engineering expertise with the latest advancements in artificial intelligence (AI) and machine learning (ML), firms can move to a predictive maintenance model and reduce O&M costs by up to 30%.

Shifting trends in software adoption for wind energy O&M The wind energy industry has often been reluctant to adopt digital technology advances. But in a post-subsidy market, the need to improve efficiencies is far greater than it was previously. It has become increasingly common and affordable for wind turbines to be fitted with digital sensors which log invaluable

data regarding the performance of the turbines. At this stage, wind farm owner-operators are failing to unlock the full potential of this data.

However, this is changing. Using the vast quantities of data generated by pre-installed sensors for detecting and measuring health indicators such as drive train vibration, O&M experts can work with data analysis specialists to train algorithms to detect issues in wind turbines before they emerge.

When combined with the specialist knowledge of O&M professionals, these algorithms can be trained to diagnose problems with accuracy rates close to 99%. It is then possible to have an entire site of digitalized wind turbines, connected to the Internet of Things (IoT) and to each other, delivering performance and health data to remotely situated O&M teams.

Using AI means that the data analysis can be automated, so that large data sets, beyond the capacity of an engineering team to analyze in a timely fashion, can be scrutinized for trends that indicate health changes. Engineering expertise is vital to the process, as it ensures that the algorithms are trained properly to distinguish which trends were important, and what a particular trend signature means for a wind turbine’s performance and reliability.

Cloud computing reduces the cost barriers to this cutting-edge analysis even further, by enabling wind farm owner-operators to process large amounts of data and access it easily, providing a scale of computing resource that was previously unattainable within the wind industry.

This allows in-house teams to run predictive maintenance at a lower cost, but still use the support of engineering expertise as needed.

Across the 9 GW of wind capacity that

WINDPOWER ENGINEERING & DEVELOPMENT

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THE WINDS OF CHANGE

ONYX InSight monitors, 20% of those assets have already adopted this do-it-yourself approach. The universal accessibility of the cloud means that the physical location of wind farms, O&M teams and expert engineers is a non-issue in relation to the monitoring and analysis of wind turbine performance.

The trend toward digitalization is certainly gaining momentum. In September 2019, ONYX hosted its annual North American Technical Symposium, gathering together leading experts in the wind O&M field, as well as owner operators in the industry. Among the attendees, 51% confirmed that their organization was aligned to adopt AI and ML to monitor their wind turbines in the near term, while 22% have already employed the technology in their O&M practices.

The risks of adopting AI and ML without the right digital tools Wind farm operators will need a fully thought-out strategy for adopting new and advanced technology. Without one, they risk costly delays during implementation. As with all major process changes, there is the potential risk for problems to arise if there is a lack of careful management at all stages.

It is of paramount importance that all relevant personnel receive the training they need well ahead of time, and that workers within the O&M team are clear on their roles and responsibilities.

To add to the challenge, the technical element requires extra care. There is a tendency among some to jump on the AI bandwagon because AI and ML are exciting new technologies. This is made more difficult by views of AI and ML as cure-alls, capable of solving every problem and optimizing for every situation. The reality is that AI and ML are most effective when directed at specific, targeted problems, and the technologies need to be "trained" on data sets from experienced, expert wind industry O&M engineers before they can unleash their full power. Wind farm owneroperators must ensure that they can leverage this real-world expertise — and combine it with the right technology — before they make significant forays into the digital world.

When handled correctly, the wind energy industry stands to gain enormous savings from using AI and ML for predictive maintenance. At the same time, renewable energy is set to become a significantly larger component of the

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global energy mix, and, in regions such as the UK and Northern Europe, wind energy will become the largest energy source.

Consequently, wind energy infrastructure is becoming a critical part of the national energy grid. There have long been concerns about cyberattacks on nuclear power plants in particular, but as wind energy becomes more prominent, it will present a more attractive target to rogue states, terror organizations and even cyber criminals.

Increasing the connectivity of wind farms is a necessary step toward cementing wind power’s eventual status as one of the primary forms of energy generation in the 21st century, but it also makes wind infrastructure more vulnerable.

It is necessary to learn and grow from past outages such as the 2016 incident in Ukraine, caused by hackers targeting the national power grid. Cybercrime is no new concept, as hackers have been able to hold energy firms to ransom with viruses. If the wind farm has its servers infected with malicious data and is shut down, it could cost wind farm owners millions in lost revenue costs until the problem is resolved.

Cyber security may seem daunting, but fortunately, there are simple and relatively cost-effective steps that can be taken to reduce the risk of incursions. These include installing in-line firewalls between turbines, investing in operations technology (OT) security software, and ensuring data is encrypted to a high standard. These measures can have the added benefit of lowering insurance premiums as well.

It is clear that wind farm owners can’t afford to neglect AI and ML in their O&M models.

By staying ahead of emerging trends in wind O&M technology, companies can gain a strong competitive edge, cut their operational costs and reduce the LCOE of their assets. Forwardthinking wind owners can protect themselves better against the risks of a post-subsidy market, extend the life of their assets and properly protect against emerging asset risks — if they are prepared to intricately adopt advanced computing technology across their portfolios. WPE

www.windpowerengineering.com

MAY 2020

A Radical Change in Bolting is Coming Your Way Norbar Torque Tools Introduces a New Generation in AC Powered Torque Multipliers

EvoTorque 2 ®

It’s Time to Change the Way You Think About AC Powered Torque Multipliers • • • • • • • • •

Operating ranges from 100 lb-ft to 4500 lb-ft Measures in Torque, Torque and Angle, and Torque Audit mode for pre-tightened bolts Versions for 110 VAC or 230 VAC Lightweight at only 23lbs.

Factory calibrated and certified to ± 3% accuracy regardless of fluctuating voltages USB and Bluetooth® 4.0 data transfer (also called Bluetooth® Smart) 3,000 readings in internal memory, time and date stamped Includes PC software ‘EvoLog’ for data management and tool configuration From factory to field; for fabrication, installation, verification and maintenance

Norbar Torque Tools, Inc.

Let’s Talk Torque

440.953.1175 PH 440.953.9336 FX inquiry@norbar.us norbar.com

WHY DO BOLTS LOOSEN?

BY JULIE PEREYRA • SALES ENGINEER • NORD-LOCK GROUP

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epending on the application, bolt loosening can have profound consequences. One loose bolt can bring a whole production plant to a standstill and cost a company thousands. In other applications, loose bolts can pose a significant safety hazard. So, why do bolts loosen?

Broadly speaking, there are two main causes: 1.

2.

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Spontaneous loosening – shock, vibration, dynamic load Slackening – settlement, creep, relaxation

WINDPOWER ENGINEERING & DEVELOPMENT

“The main causes and the consequences of failure depend on the purpose of the bolted joints, on the environment and usually on the industry,” said Georg Dinger, Siegenia-Aubi KG, who has studied the causes and effects of bolts self-loosening extensively.

“For example, the petrochemical industry is primarily concerned with corrosion problems, while fatigue and vibration loosening are usually of minor concern. On the other hand, the automotive industry would probably name self-loosening and corrosion as the two main problems. The primary

www.windpowerengineering.com

concerns for the structural steel industry are joint slip and corrosion, but selfloosening and leakage are less common.

The aerospace industry would probably list fatigue first.”

Repeated relative displacements between the contact surfaces, which are under the influence of the shank torque and result from the thread pitch torque, can lead to a gradual rotation of the bolt or the nut.

“This causes a bolt preload loss and consequently a loss of function in the bolt connection. The effect is well known, but prevention is usually performed

MAY 2020

experimentally only after the occurrence of self-loosening events,� Dinger said.

An ounce of prevention To prevent spontaneous bolt loosening, the slip between the joined parts needs to be eliminated or at least reduced to below critical levels. This can be achieved by increasing the axial tension or the friction between the clamped parts or decreasing the cyclic loading (for example, shock, vibration or cyclic thermal loading).

Another common method is to increase the friction between the bolt

MAY 2020

threads. Although there are several effective ways to do this, some have disadvantages worth considering.

For example, glue or adhesives can be an effective friction-based method, but dried glue can be problematic when dissembling and removing the bolt.

Furthermore, increasing the friction between threads would decrease the achievable preload at a specific torque level. Locking wire is a common method in the aviation industry.

Fatigue is permanent damage or deformation in the bolt and clamped parts. It’s caused by loss of preload

resulting in an opening in the joint. Spontaneous loosening and slackening are the two basic mechanisms for loss of preload.

Essentially, spontaneous loosening or rotational self-loosening occurs when a bolt rotates loose because of shock, vibration or dynamic loads. Even a slight rotation can be enough for a bolted joint to lose all of its preload. This is the most typical cause of bolt loosening.

Slackening is caused by three mechanisms: settlement, creep or relaxation.

WINDPOWER ENGINEERING & DEVELOPMENT

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“Settlement is critical when it happens due to dynamic loads. It is the permanent deformation of the clamped material when the joint is subjected to the increase of stress from dynamic working loads,” explained Harlen Seow, technical manager with the Nord-Lock Group. “Most parts of a bolted joint will revert to shape after being released if the stress in the parts has not gone beyond their yield strengths.”

This means some materials in the contact surface, such as paint, will most likely deform permanently.

Creep is a permanent deformation that occurs due to long-term exposure to high levels of stress below the yield strength of the materials in the joint. It’s more severe in high-temperature applications.

Relaxation is when the microstructure in the materials of a joint restructure, converting existing elastic deformation to plastic deformation over a period of time. Unlike settlement or creep, the clamp length does not change, which makes it more difficult to detect.

“One way to measure preload loss is to measure bolt length after a period in operation and compare to the bolt length immediately after tightening,” Seow said. “However, this will not detect relaxation, which makes it more problematic.”

The key to avoiding fatigue is good design, which has grown in importance in recent years because of the increased demands on many bolted joints and increased use of lightweight materials. It’s important to avoid solely focusing on the tensile capacity of bolts while overlooking other parameters — such as elasticity and

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WINDPOWER ENGINEERING & DEVELOPMENT

W H Y D O B O LT S L O O S E N ?

stiffness, which can also be important.

“Correct joint design is the key to achieving a high strength friction grip connection with a high preload level, and thus a high slip resistance over the entire lifetime,” Dinger said. “Up until now the focus for design engineers has been on the failure with bolts breaking. Other failure mechanisms have become more and more important as performance is increased and the weight of joints is decreased. The mechanisms of preload relaxation and self-loosening are more and more common in lightweight designs.”

Depending on the bolt, the application and the cause of preload loss, there are generally multiple options for designing more optimal bolted joints.

“In cases where there’s thermal loading, the joint can be optimized by choosing materials with equal thermal expansion coefficient for the clamped parts,” Dinger said. “To help minimize settlement and maintain a high preload during operation, you can reduce the roughness between contact surfaces. Measures such as fine hole diameters or toothed surfaces can help minimize relative displacement.”

Overall, achieving the optimal bolted joint involves factoring in multiple variables and design options.

“In general, a good bolted joint is made up of very elastic bolts and very stiff clamp parts, and there are different ways of achieving this," Seow said. "One way of improving bolt elastically is to have long clamp length. But if you have a flange, where the clamp length can’t be too long, you can change the design by using more but smaller bolts. So instead of using five bolts, you can use ten smaller bolts, which will create a more elastic joint.” WPE

WINDPOWER ENGINEERING & DEVELOPMENT

15

SETTLEMENT IS CRITICAL WHEN IT HAPPENS DUE TO DYNAMIC LOADS. IT IS THE PERMANENT DEFORMATION OF THE CLAMPED MATERIAL WHEN THE JOINT IS SUBJECTED TO THE INCREASE OF STRESS FROM DYNAMIC WORKING LOADS.

RawFilm | Unsplash

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WINDPOWER ENGINEERING & DEVELOPMENT

www.windpowerengineering.com

MAY 2020

How the

RENEWABLE

ENERGY SECTOR

WILL GROW despite waning tax credits Julie Desimone & Jimmie Williams • Moss Adams

Federal

tax credits for renewable energy are waning. The federal renewable electricity production tax credit (PTC) was supposed to end in 2019.

However, Congress passed extensions of the PTC in December 2019 for projects beginning construction before December 31, 2021. Specific sectors, like the solar industry, saw the investment tax credit (ITC) drop from 30% to 26% in 2020.

The Coronavirus Aid, Relief, and Economic Security (CARES) Act — a $2 trillion stimulus plan signed into law on March 27, 2020 — won’t extend tax credits or offer direct pay provisions for solar and wind projects.

This trend is set to continue and it’s impacted the way renewable energy companies do business.

Impact of corporate influx The renewable energy industry has been forced to pivot its business model

MAY 2020

away from federal tax benefits. In the past, companies could sell megawatts at a cheap rate and still make a decent profit because of the federal production and incentive tax credits. Now, renewable energy companies are finding secure funding for the lifespan of their assets without the federal government’s assistance or a heavily reduced level of assistance.

While the need for renewable energy remains high, primarily due to state mandates and social responsibility, corporate trends include shorter and more competitive power purchase agreements (PPAs) or renewable energy companies selling directly into the market. This creates pressure to make projects more cost and production efficient. There are new corporate players in the renewable energy market due to a variety of reasons, including social responsibility, high energy demands (data centers) and securing of more economic electric rates.

The need for renewable energy is increasing, and as costs continue to decline, corporations will see renewable energy as an attractive sector, even without tax credits.

Google is a great example of a corporation that took it upon itself to push renewable energy. It started buying longterm wind energy in 2010 and declared the company 100% reliable on renewable energy sources for global operations in 2017. Google also signed a wind and solar investment deal worth up to $2 billion in 2019 to continue to provide its campuses with electricity from renewable resources.

The deal grew its green energy portfolio by 40%.

The concept of corporate sustainability is not driven entirely from a pricing standpoint; in many cases, companies continue to pay a higher price for renewable energy. They must have the desire to do their part and reduce their fossil fuel use.

WINDPOWER ENGINEERING & DEVELOPMENT

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The 225-MW Great Western Wind Project serves Google’s data center in Oklahoma. EDF

It’s more of a socioeconomic decision driven from an investor standpoint. Like Google, corporations want to be viewed as leaders that drive environmental awareness. (See Top 5 Renewable Energy Trends for 2020.)

Decreasing generation costs Corporations have been motivated to enter the renewable energy space because it’s seen as a new profit area. Since the reduction of renewable costs, markets are equalizing, and renewable energy has become more competitive with fossil fuels primarily due to the decreasing costs of utility-grade renewable energy generation. Price decreases come from a combination of scale in production and improvements in technology.

Wind and solar have lower or comparable total cost of generation than the majority of conventional generation sources.

Certain technologies — such as onshore wind and utility-scale solar — became cost-competitive with conventional generation several years ago on a new-build basis, and they continue to maintain

MAY 2020

competitiveness with the marginal cost of existing conventional generation technologies.

Remaining challenges Though the renewable energy industry is stabilizing in many ways, generation demands, cost of manufacturing and state requirements are a complex, ever-moving target, and new changes to the industry arrive each day. While opportunities evolve in this sector, the industry will continue to struggle with some significant challenges.

Storage Major questions remain about the direction of renewable energy when we look at the United States as a whole. The sector is still working to tackle the issue of cost-efficient energy storage.

While a continued decline of fossil fuels is expected, without efficient storage solutions, it’s unlikely that the use of fossil fuels will discontinue. If a cost-efficient energy storage solution is found and manufactured, it will be a significant game changer for the renewable energy industry.

WINDPOWER ENGINEERING & DEVELOPMENT

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Insufficient infrastructure As plans for coal and less efficient generation sources term out or are retired, there’s a need for additional power generation. This raises the questions — where is it going to be generated, and is there sufficient transmission infrastructure in place to deliver the energy to the markets where it’s needed?

With the combination of renewable energy mandates and trends toward corporate sustainability, utilities are looking to fill the gap with renewable energy sources — if the utility already has a strong base load component.

However, renewable energy tends to be generated further away from where it’s needed, especially when the production is large scale. For instance, wind power is often generated out in desert areas like Palm Springs or West Texas where there’s lots of space but a low population.

You need a reliable transmission system that has capacity to get the power where it needs to go. This continues to be a challenge across the United States.

The system also needs to be designed to sustain peak periods. Wind and solar are intermittent power sources. The greatest amount of wind generation isn’t necessarily generated during times of peak demand, so until reliant and efficient energy storage is created, we need more of it.

Smart grid solutions have been introduced to the market with technology that has the capacity to help manage existing electricity in your grid. Technology like this will continue to become more important when intermittent sources like renewables become more incorporated into power grids; it will be needed to manage the energy load to ensure there’s not frequent brown or black outs.

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Liquidated damages Renewable energy companies enter into PPAs with power and utility companies to finance their projects.

Utilities and corporations buy the power generation coming off the facility, but if they don’t perform on that contract, liquidation and other types of damages could go into effect.

For example, a renewable energy company might sell a certain amount of wind power to a utility company for $75/MWh for an agreed upon number of years. If the utility company fails to manage its facilities correctly and isn’t able to use the full amount

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GROWTH DESPITE WANING TAX CREDITS

of wind power in the contract, the renewable energy company could turn to the open market to sell the power. If it’s sold at $15/MWh on the open market, the utility company could be responsible for the remaining $60 of the original cost in the contract.

The city of Georgetown, Texas, experienced this issue in 2018 when it purchased 100,000 MWh, but its customers used less than 77,000.

Also, if a renewable facility doesn’t meet its minimum megawatt-hour requirements, it could be required to make the counterparty financially whole.

Looking ahead Moving forward, the renewable energy industry will continue to increase production and the renewable energy business models will be less dependent on federal incentives.

Corporations are focused on reliability and keeping costs contained. Renewable energy companies will need to understand what’s driving other corporations to seek out renewables. The renewable energy market is unique, and the needs of a car company are very different than those of a technology company.

Are they looking to achieve a balanced portfolio? Do they want more diversification of risk? Below are some steps renewable energy companies can take as they look to the future: • Watch contract language carefully to protect against industry changes that could have a detrimental impact on their business.

• Model scenarios that don’t involve federal tax credits.

• Gain a greater understanding of energy markets and the volatility in those markets.

• Seek better means of energy storage to increase industry demand. WPE

120 MW of the 154-MW Rock Falls Wind Project in Oklahoma is purchased by Kimberly-Clark to power a portion of its North American manufacturing operations.

EDF

MAY 2020

WINDPOWER ENGINEERING & DEVELOPMENT

21

Bringing

FISHING &

WIND COMMUNITIES t o g e t h e r t o s i t e U. S . offshore wind projects

In

April 2019, the Embassy of the United Kingdom and the state of New York brought two veteran British fishermen across the Atlantic Ocean to speak about their experiences working with offshore wind developers. While offshore wind is relatively new to the United States, with just one wind farm and 30 MW of capacity, the industry has exploded in Europe, with over 100 wind farms and more than 22,000 MW of capacity.

The British fishermen described an early disagreement: an offshore wind developer had done its surveys

22

WINDPOWER ENGINEERING & DEVELOPMENT

and determined the placement of a transmission cable, even though this meant laying the cable over a hard rock cliff where it would be exposed to damage and interfere with longstanding fishing activity. The fishermen recognized that this placement would be bad for both industries, hurting the cable’s longevity and creating a potential snag for fishing activity. The two industries hit the drawing board and found an alternative plan: the fishermen knew of nearby soft bottom ocean habitat where the cable could be buried, reducing the developer’s risk and preserving fishing in the area.

www.windpowerengineering.com

Issues like these are ones where fishermen’s knowledge of the seas they have worked on their whole lives – and previous generations worked on before them – can be invaluable, both for maintaining their livelihoods as offshore wind farms are constructed in or around fishing grounds, and for helping developers make the best decisions for their wind businesses.

MAY 2020

By

HENRY SCHNEIDER

SENIOR COMMUNICATIONS ASSOCIATE STOVE BOAT COMMUNICATIONS

It was in this spirit that in 2018, the Responsible Offshore Development Alliance (RODA) was formed. Comprised of fishing industry members from every Atlantic coastal state from North Carolina to Maine, as well as Pacific coast members in California, Oregon and Washington, RODA works directly with developers, regulators, scientists and other experts to promote coexistence

MAY 2020

between the offshore wind industry and fishing communities. To minimize conflicts with commercial fishing, RODA is committed to applying scientific and evidenced approaches to the expanding U.S. offshore wind industry.

Although there is only one U.S. offshore wind farm currently in operation and located in state waters, 16 sites have

been leased throughout New England and the Mid-Atlantic, with additional sites proposed in both the Atlantic and Pacific. Offshore wind development is also complicated by the sheer number of developers, fishery sectors and regulators in play. On the regulatory side alone,

WINDPOWER ENGINEERING & DEVELOPMENT

23

BRINGING FISHING & WIND COMMUNITIES TOGETHER

the National Marine Fisheries Service (NMFS), the Bureau of Ocean Energy Management (BOEM), the U.S. Coast Guard, regional fishery management councils and state agencies all have some jurisdiction over offshore wind and fishery interactions. With so many different groups involved, RODA’s ability to speak with a unified voice on behalf of the fishing industry is critical to the process.

One of RODA’s most important projects – conceived during a meeting between RODA and Ørsted leadership in 2019 – is its Joint Industry Task Force with wind developers, a first-ofits-kind initiative created to improve direct communications between the two industries. In addition to RODA’s fishing members, the task force consists of wind developers Ørsted, Equinor, Vineyard Wind, Mayflower, Atlantic Shores Offshore Wind, Avangrid and EnBW, comprising almost every offshore wind leaseholder on the Atlantic coast. The driving concept behind the task force is to take the best lessons learned from all regions — like the British cable example — apply them early and often, and continually improve upon them to reduce risk for both industries.

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WINDPOWER ENGINEERING & DEVELOPMENT

“The Joint Industry Task Force is bringing the offshore wind and fishing industries together to pool their knowledge in a way that’s never been attempted before,” said Peter Hughes, RODA’s Chairman and Director of Sustainability at Atlantic Capes Fisheries. “It’s groundbreaking work.”

The task force first convened in June 2019 to determine how the industries could best work together and finalize a charter, with principles including promoting coexistence, identifying areas of conflict and cooperating to identify solutions and ensuring fishing representation in the offshore wind process. Last October, the task force co-convened a Joint Industry Educational Forum in Warwick, Rhode Island — a twoday informational exchange in which fishermen, developers, state leaders and regulators presented on everything from U.S. fisheries law to the physical components of a wind project to fish stock assessment surveys. More recently, the task force prepared a joint letter to BOEM on draft navigation guidelines and created a survey for mariner input on what kinds of navigational aids would benefit them most, from lighting and markings on turbines to AIS (automatic identification systems) to sound signals.

“From our experience in other regions around the world, we believed that creating a forum made up of a broad fishing

www.windpowerengineering.com

MAY 2020

BRINGING FISHING & WIND COMMUNITIES TOGETHER

geographic and gear type representation, alongside offshore wind developers, only leads to better communication and outcomes for both industries,” said John O’Keeffe, head of marine affairs for Ørsted. “We must still maintain strong direct ties with other regional fishing organizations and state and federal agencies, but having a national body can be extremely helpful.

We won’t agree on everything, but solid outcomes and practical solutions can be achieved.”

In many ways just as important as the concrete developments that have emerged from the task force is the collaborative space that has resulted for both industries to work together. Through the task force, wind developers have an on-going and regular means to inquire about commercial fishing ideas and concerns, and vice versa. Some task force members have even engaged RODA in site-specific, detailed layout meetings on their wind projects – something that almost certainly wouldn’t have happened before the task force brought the two industries into closer collaboration.

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BRINGING FISHING & WIND COMMUNITIES TOGETHER

“One thing the fishing industry has learned from the task force is that not all offshore wind developers relate to the U.S. commercial fishing industry the same way,” said Annie Hawkins, RODA’s Executive Director. “And I think the dialogue of the task force has provided offshore wind developers with a much deeper appreciation of the significant differences of needs across our different fisheries.”

Plenty of issues to be resolved remain as offshore wind moves forward in the United States. As relationships continue to grow and trust evolves, task force participants hope that early identification of potential conflicts and adaptive learning once projects begin operations will minimize conflict in the future. Structured communications can assist in identifying and de-risking potential issues long before they become entrenched sources of conflict.

For example, some fisheries are managed on a “days at sea” basis whereby fishermen are allotted a certain number of days to make their catch – without fishing input, wind developers wouldn’t have known that spending extra time transiting offshore wind areas can directly impact how much fishermen are able to catch.

Other fisheries use low-altitude spotter planes that radio down to fishing boats where to go to catch schools of fish. These planes wouldn’t be able to fly through large wind energy areas. In others, such as tuna fisheries in several regions, fishermen who have traditionally pursued their catch by following birds are concerned about potential disturbances.

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WINDPOWER ENGINEERING & DEVELOPMENT

Through initiatives like the Joint Industry Task Force, RODA is able to bring the fishing industry’s knowledge and concerns directly to wind developers early in the process. And because of the open channels of communication created by the task force, the industries have the ability to collaborate on solutions early to avoid confrontation later on. As offshore wind becomes a major player in the U.S. energy system, this is the type of winwin work that must occur to ensure the industry is successful and historic U.S. commercial fishing communities are able to continue their way of life. WPE

THE JOINT INDUSTRY TASK FORCE IS BRINGING THE OFFSHORE WIND AND FISHING INDUSTRIES TOGETHER TO POOL THEIR KNOWLEDGE IN A WAY THAT’S NEVER BEEN ATTEMPTED BEFORE.

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When a strike occurs, current flows to ground through the lightning protection system. The system’s resistance to ground should be measured regularly to ensure that the protection will work when needed. For these measurements a low resistance ohmmeter, like the DLRO10HD and DLRO10HDX, should be used.

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EDDY CURRENT

PROBES ADD FLEXIBILITY TO

WIND TURBINE NONDESTRUCTIVE TESTING

BY B I LL ZIE G E N H A G E N • PR OD UCT MA N A GER • ZET EC

28

WINDPOWER ENGINEERING & DEVELOPMENT

www.windpowerengineering.com

MAY 2020

EDDY

current technology has long been used in nondestructive testing (NDT) for wind turbine tower welds, drivetrains and a wide range of spot inspections in O&M programs. It’s a fast, accurate, chemical-free method for detecting surface and sub-surface indications that are too small to see with the naked eye, including cracks, pits, corrosion and damage due to impact or fatigue.

Eddy current testing has the added benefit of producing an electronic inspection record for advanced analysis and reporting, a big advantage over dye penetrant testing (PT) and magnetic particle testing (MT).

Unlike PT or MT, eddy current results are digital and can be analyzed, saved, shared, stored and compared at any time.

Eddy current can also “see” through nonconductive coatings like paint without technicians having to pretreat the surface — a time-consuming and messy process.

Eddy current testing involves using a portable instrument and a probe with a coil that fires electronic currents into the material. Eddy current array (ECA) probes have multiple coils that fire at coordinated times and can capture more information in a single pass, transforming the eddy current inspection from a process that might last several minutes per joint to one that takes seconds.

One practical limitation of eddy current technology is that the coils in the probe need to be close to the material for accurate flaw detection and signal quality. It’s a challenge because of the various component geometries, weld shapes, rough surfaces and hard-to-reach areas on a wind turbine.

Consider the inspection of butt welds on a steel tower. Fabricating towers capable of resisting severe stresses and variable loads requires thick, high-strength steel plates and multi-pass complete-penetration butt welds.

The technician has to keep the probe closely aligned with the positive curvature of the tower exterior, the positive curvature of the circumferential weld crown bead and the non-uniform surface of the weld itself.

MAY 2020

The job is made more complex by how difficult these welds and components are to reach.

Thus, there is a need for a probe design that can keep the excitation coils and sensing devices closely and properly aligned with the surface of the material as the technician applies the probe to the surface. Over the years, probe suppliers have come up with a variety of methods to accomplish this.

Customized probes One strategy is to design a surface array probe that’s shaped for one specific application or component, like gear teeth, rivets, bolt holes or something that has to be subjected to repeated NDT. Using CAD drawings and 3D printing technology, it’s possible to manufacture an eddy current probe that’s precisely formed to fit an exact shape or surface. Though it’s designed to do only one job, a custom-made probe can be extremely effective at producing consistent data acquisition conditions over and over again.

Flexible probes Another approach is to use an ECA probe with a flexible, durable wear surface that allows the coils to bend and remain nominally perpendicular to the surface when that surface is rough, irregular or complex. In the case of a weld, for example, a flexible surface array probe with just 2 in. of coverage can encapsulate the weld bead, transition zone and heat-affected zones in a single pass.

This type of flexible probe can conform and adapt to different surfaces and contours, and it can handle a range of ECA inspections on the same job ticket: for example, a technician can inspect welds on a curved tower and weld joints on turbine rotors with the same flexible surface array probe.

For very high weld crowns, some surface array probes have “+point” coils at the tip of the probe. These types of coils can be especially effective when examining the top of the weld.

One important consideration is the material on the wear surface. The thickness of the wear surface will affect the proximity of the coils

WINDPOWER ENGINEERING & DEVELOPMENT

29

EDDY CURRENT PROBES

to the material as well as the probe’s overall flexibility and eddy current signal quality.

In some cases, the flex circuit may not be durable enough to withstand repeated abrasion against rough metal surfaces. Probe manufacturers offer a variety of materials as a wear surface, including plastic films and abrasion-resistant fabrics like SuperFabric.

Modular approach Customized and flexible surface array probes can quickly and accurately test a wide range of materials and geometries but the entire assembly must be replaced if one element of the probe wears out or fails.

One new approach to improving the versatility and service life of ECA probes is a modular one. Last year, Zetec introduced Surf-X, a flexible ECA probe with swappable

30

WINDPOWER ENGINEERING & DEVELOPMENT

coil sets for specific applications. Each probe is comprised of an electronics module and detachable encoder that can be used interchangeably with different array probe coil sets. Users in the field can switch out a coil set in less than one minute.

Currently, Zetec offers five coil sets, including one set for welds that uses a mix of 32 array coils and two +point coils for complete inspection coverage of butt and t-welds; two versions of very flexible tape probes for inspecting small surface flaws on complex geometries such as turbine dovetails; and another set for a range of surface array testing applications where PT or pencil probes might be used today. The encoder can connect in multiple locations on both the handle and electronics module. The module, encoder, and cables can be re-used, saving time and money.

www.windpowerengineering.com

During a weld inspection, a flexible surface array probe with just 2 in. of coverage can encapsulate the weld bead, transition zone and heat-affected zones in a single pass.

Zetec

MAY 2020

EDDY CURRENT PROBES

COMMON NDT TECHNOLOGIES FOR WIND TURBINE INSPECTIONS

The effectiveness of an eddy current probe depends on getting the excitation coils and sensing devices aligned with the surface of the material, even when the surface is rough, irregular or complex in shape.

Zetec

The coil sets have four wear-surface options: no wear surface on the tape probes for inspecting small indications on smooth materials; a thin UHMW plastic wear surface to protect coils and reduce lift-off; a cloth wear surface for protecting the array coils on smooth or polished surfaces, like gear teeth; and SuperFabric for protecting array coils on rough surfaces like butt and t-welds.

More coverage and versatility Regardless of whether you use a custom probe shape, a flexible surface array probe or a modular approach, today’s ECA probes provide greater inspection coverage in a fraction of the time compared to PT, MT or pencil probes.

The key is to focus on a probe’s flexibility — literally — in terms of the surfaces and geometries it can handle, and in its ability to help technicians be more productive in their inspections while maximizing the value, versatility, signal quality and service life of the probe. WPE

MAY 2020

Penetrant Testing (PT): A simple method for identifying surface-breaking defects and discontinuities in metal and other nonporous materials. PT involves applying a colored liquid to the surface and allowing it to be drawn into minute openings by capillary action. Defects become visible under ultraviolet light or by the contrasting color of the dye being used.

Magnetic Particle Testing (MT): Very fine ferromagnetic particles are applied to the metal and are drawn into discontinuities on the surface.

Effective only on ferromagnetic materials.

Eddy Current Testing (ECT): In simple terms, ECT involves placing a probe or coil to a metal surface.

The probe generates a changing electromagnetic field that induces electrons to flow in the material.

Any cracks or changes in metallurgical structure will distort the flow; these distortions are captured and analyzed by an instrument and displayed for the technician to review. The results are precise, and the digital record allows technicians to share, store, and review inspection data.

Ultrasonic Testing (UT): Ultrasonic testing uses pulses of high-frequency sound energy to detect surface and subsurface cracks and other defects.

These pulses come from a probe which the technician moves over the surface under inspection.

The probe emits ultrasonic waves into the material at precise intervals and a set angle; when a sound wave encounters a defect, some of that energy is reflected back like an echo and is captured on a display for the technician to interpret.

WINDPOWER ENGINEERING & DEVELOPMENT

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