AMERICAN GALVANIZERS ASSOCIATION

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Hot-Dip Galvanized Renewable Energy

Renewable energy provides clean, sustainable power for many different industries and is becoming an increasingly popular alternative to traditional energy. Renewable

energy such as solar, wind, and hydro-electricity are expected continuously to grow because of tax incentives and the nation’s growing interest in maintaining an environmentally

conscious society. As the renewable industry grows, one critical component remains constant – corrosion protection. For more than 75 years, hot-dip galvanized (HDG) steel has played an

integral role in the corrosion protection of structures in the power generation industry.

In order to protect these new, multi-million dollar ventures from the damaging and costly effects of corrosion, a proven method is needed. Hot-dip galvanizing provides a sustainable, cost-effective and

maintenance-free solution that is 100% recyclable, a natural, durable solution to the corrosion epidemic facing the renewable energy sector.

Here are some areas where HDG is commonly used in renewable energy structures:

SUSTAINABLESolar, wind, and hydro-electricity are renewable resources and plentiful energy options that provide sustainable, green energy for current and future generations. Sustainable development is the social, economic, and environmental commitment to growth and development that meets the needs of the present without comprising the ability of future generations to meet their needs. The world needs renewable energy to provide sustainability for the future. Changes in technology have given rise to these renewable energy sources which have a very low environmental impact, are widely available, and are naturally replenished throughout the atmosphere.

The zinc used in the hot-dip galvanized coating is a natural, healthy metal. As the 27th most abundant element in the Earth’s crust, zinc is readily available and r100% recyclable; creating an infinitely renewable resource. The natural, renewable, and durable zinc of the hot-dip galvanized coating will ensure renewable solar, wind, and hydro-electricity power can be generated without interruptions or impact to the environment.

AESTHETICSRenewable energy projects have a wide variety of applications, from individual home installations to large solar power plants, wind farms, and hydro-electric dams; all of which generate clean, renewable energy for human consumption. Keeping these structures corrosion-free and aesthetically in line with the surrounding environment is a desirable characteristic of the finish of hot-dip galvanizing. The silver-gray appearance of the coating compliments many domestic, natural, industrial environments.

As we move towards a renewable energy future, power generation is no longer hidden far away from the population’s daily interaction, but is integrated within our commercial and residential communities. Aesthetics have become an important factor when choosing renewable energy and with the help from the hot-dip galvanized coating; these structures will be able to naturally blend in with their environment and provide a safe, corrosion-resistance energy source for generations to come.

There is an ever increasing drive towards buildings and cities that are designed to be run with renewable energy, and the city planners and designers must find a way for the renewable energy sources to fit in with the pre-planned designs1. Beauty is a subjective idea. What is needed to bridge the gap between the larger desire for a renewable future and a community’s negative reaction is a sustainable and artistic solution.1 The hot-dip galvanized coating provides this aesthetic appeal in a array of environmental settings, and can begin to bridge this gap.

Hydro-Electricity Anchor BoltsElectrical BoxesWind Poles

Solar EnergySolar Control BoxesSolar RackingSolar-Panel Supports

Wind PowerTower LaddersTower SupportsWind Mill Towers

A silver-gray natural finish compliments it’s environment

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MAINTENANCE-FREEOnce installed, solar, wind, and hydro-electric projects continually store energy from the sun, wind, and water. This exposes the project to a constant stream of harsh environmental factors and can require costly maintenance fees. Because hot-dip galvanized steel remains maintenance-free for decades, it ensures no expensive, specially trained personnel will have to be sent out to a rural or offshore area to service the structure. Renewable energy projects can be multi-million dollar investments, and when working at full capacity, will eventually recoup the costs of the investment.

Galvanizing these renewable energy structures ensures they will function properly for decades with no maintenance, repairs, or touch-ups. The Time to First Maintenance chart (Figure 1) shows the thickness of zinc in five environmental conditions and how long the galvanized coating will last until maintenance is necessary. Hot-dip galvanizing ensures renewable energy projects have the longest service life possible by protecting them and eliminating maintenance for at least 75 years or often for the life of the project.

DURABLERenewable energy projects can face some of the harshest environments. Solar projects are constantly exposed to UV rays, extreme temperatures, and weather. Wind projects are developed in high wind areas and are constantly exposed to beating sun, rain, in additional to the winds that batter the structure with abrasive debris. Hydro-electric projects use many hollow pipes and are in an extremely corrosive, moist environment. All of these renewable energy sources must have a way of fighting corrosion in their environments. Hot-dip galvanizing can provide the protection that is needed thanks to its superior barrier protection. Zinc effectively isolates the steel from the environment, therefore allowing the steel to maintain its physical and chemical properties. The zinc-alloy intermetallic layers provide a nearly an impenetrable adhesion with no flaking, cracking, or peeling.

In addition to barrier protection, the zinc in the galvanized coating also protects the steel cathodically. Zinc will sacrificially corrode to protect the underlying steel. On top of barrier protection, another aspect of hot-dip galvanizing that resists corrosion is the zinc patina. Zinc, like all metals, begins to corrode when exposed to moisture and free-flowing air. The zinc patina forms when corrosion elements build up on the surface of the zinc, slowing the corrosion rate. This is particularly useful for solar, wind, and hydro projects because the zinc patina offers nearly impenetrable protection from the elements. With the harsh, unforgiving climates, weather and constant UV exposure that renewable energy projects are subjected to, the durability of hot-dip galvanizing is unmatched.

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*Time to first maintenance is defined as the time to 5% rusting of the steel surface.

1 mil = 25.4μm = 0.56oz/ft2

Figure 1: Time to First Maintenance Chart

Copyright © 2016 American Galvanizers Association. The material provided herein has been developed to provide accurate and authoritative information about after-fabrication hot-dip galvanized steel. This material provides general information only and is not intended as a substitute for competent professional examination and verification as to suitability and applicability. The information provided herein is not intended as a representation or warranty on the part of the AGA. Anyone making use of this information assumes all liability arising from such use.

American Galvanizers Association6881 South Holly Circle, Suite. 108Centennial, CO 80112720.554.0900www.galvanizeit.org

1Land Art Generator Initiative. “The Aesthetics of Renewable Energy.” Jennifer Schwab. January 30, 2010

LIFE-CYCLE COSTRenewable energy projects are often in service for several decades or more and need to be able to stand the test of time. It is important to consider the initial cost, but also what the cost will be over the life of the project. Galvanized steel is durable and maintenance-free, so the only cost incurred is during the initial construction. The life-cycle cost calculator (lccc.galvanizeit.org) allows you to compare the initial-cost of hot-dip galvanizing to various paint systems. In most instances, the initial cost of galvanizing is comparable with those of paint systems. However, over time, hot-dip galvanizing will deliver substantial savings, through deferred maintenance costs, repairs, and touch-ups. Utilizing hot-dip galvanizing in solar projects will protect the project and save maintenance costs for decades.

SUMMARYRenewable energy will continue to be a popular choice to meet rising energy demands. Utilizing hot-dip galvanized steel in these projects is a sustainable choice for corrosion protection because of its maintenance-free durability, saving millions over the life of the structure without repairs or touch-ups during the life of the project. Galvanized steel protects your investment and contributes to a sustainable future in energy production. Hot-dip galvanizing should be the choice for corrosion protection for the increasingly environmentally conscious population.

Calculate the value of utilizing HDG in your next project. Visit lccc.galvanizeit.org

Case StudiesSTRATA SOLAR - LAWNDALE, NCThe Strata Solar farm represents a modern, clean energy, environmentally friendly, electricity producing facility. This facility generates an estimated 3.5 megawatts of electricity, or enough electricity to power approximately 3,500 homes. By using the natural resources of the sun, this facility is helping to eliminate pollution from coal fired plants, reducing greenhouse gases, toxic sludge, and other harmful contaminants.

The task of building a solar farm is a major undertaking. Everything from site selection to geotechnical surveys have to be considered and evaluated. However, one factor is almost always standard practice, no matter where the site is located: the posts will be hot-dip galvanized. This particular facility required 2,300 posts to support the solar array. Knowing that hot-dip galvanizing provides many years of useful, maintenance free life, and cathodic protection makes the decision to use galvanizing easy.

Zinc prevents rust from forming in two ways. First, although the surface of zinc metal does oxidize in a similar manner to iron, it does so much more slowly. As it ages, the zinc surface attains a layer of zinc carbonate from reactions with atmospheric carbon dioxide, which is inert to interactions with oxygen. This is witnessed in galvanized products as a patina. This patina serves as a buffer, greatly slowing further interactions with oxygen and other corrosive elements. The second way zinc protects steel is by serving as a sacrificial anode to the iron in steel. Zinc preferentially loses electrons to iron, if iron should ever need them, but only so long as there’s good contact between the metal surfaces. This means that even in cases where the zinc layer may become scratched, the underlying steel can still be protected. Learn more about Strata Solar at galvanizeit.org/strata-solar.

ASU TEMPE CAMPUS BLOCK 12 - TEMPE, AZWith the ever growing need for educational space and Arizona State University’s (ASU) commitment to Sustainable Design, ASU teamed up with the City of Tempe, AZ, when deciding the direction for their new building designated as Block 12. Block 12 will house the Del E. Webb School of Construction, 200-seat auditorium, bookstore, eateries and a Grab-and-Go Market. The 130,000-square-foot, mixed-use project expands the Tempe campus beyond University Drive and includes enhancements to the surrounding areas.

ASU also chose the Duplex System when selecting the finish on their exoskeleton steel trusses (exposed). This project includes: a ventilated façade for reducing exterior surface temperatures, integrated photo-voltaic/solar-thermal technologies, natural ventilation of atrium areas, solar hot water heating, LED lighting, and water harvesting for storage and reuse. The duplex process of galvanizing the steel and then painting it provides added protection known as the synergistic effect, this dramatically increases the time to first maintenance. Both paint and galvanizing, when used independently, provide different degrees of corrosion protection. When used together, they have increased the corrosion protection for 1.5 to 2.3 times the sum of the expected life of each system on their own. With everyone working together, they were able to provide an aesthetically pleasing high-quality learning facility as well as doing their part in minimizing the impact on the environment, for present and future generations. Lean more about ASU Tempe Campus Block 12 at galvanizeit.org/ASUTempe.

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Copyright © 2016 American Galvanizers Association. The material provided herein has been developed to provide accurate and authoritative information about after-fabrication hot-dip galvanized steel. This material provides general information only and is not intended as a substitute for competent professional examination and verification as to suitability and applicability. The information provided herein is not intended as a representation or warranty on the part of the AGA. Anyone making use of this information assumes all liability arising from such use.

American Galvanizers Association6881 South Holly Circle, Suite. 108Centennial, CO 80112720.554.0900www.galvanizeit.org

KEUKA ENERGY WIND TOWERS - AINSWORTH & FAIRFIELD, IAWhen it comes to alternative energy sources, Keuka Energy has dedicated over 20 years to research and development. After starting in hydroelectric energy, they moved into research of wind energy in 2006. Keuka owns all of the patents on the design of the wind tower, which was the first of its kind. One important feature of these towers is they allow the production of energy at lower wind speeds. Because of this, they can be used in areas not typically considered for wind power.

Since the original design had been for a painted product, Keuka worked with the galvanizer to redesign some facets of the machine in order to allow for quality hot-dip galvanizing. Hole locations and sizes had to be accounted for in baffles and motor mounts inside the towers. Consideration was given to keeping the camber of the rim assemblies. After successfully hot-dip galvanizing these wind tower sections, they were shipped to Iowa, assembled and installed.

With sustainability on the minds of so many, it is important to show alternative energy sources are a viable option. With its unique design, this wind tower can be used in areas where general wind energy is not usually considered. It produces energy at lower wind speeds and does not have a gear box requiring a great amount of draw, so a single tower can be used in many instances. Hot-dip galvanizing also plays an important role in the sustainability of these wind towers. Learn more about Keuka Energy Wind Towers at galvanizeit.org/keuka.

NORRIS DAM STEEL SUBSTATION- KNOXVILLE, TNInstalled in 1936, this galvanized steel substation handles over 100,800 kilowatts of electricity. The Norris Dam and Power Plant was the first substation built in the Tennessee Valley Authority system. Hot-dip galvanized steel encompasses the bolted lattice structures with angle posts and all structural members and bolts were hot-dip galvanized before assembly.

The dual generating units and substation handles more than 100,000 net megawatts of electricity. Galvanized steel was chosen as the preferred material for the substation. TVA’s choice of hot-dip galvanized steel has proven to be the right decision.

The substation sits at the base of the dam. It is subjected to the harsh Tennessee mountains winters, Smokey Mountain fog and mist and to the constant moisture from the dam’s overflow and spillway. It is also just below, and in full view, of the Norris Dam Visitors Center where tens of thousands of visitors view the area every year.

Upon inspection in 2014, it was determined that the steel still had an average of 2.1 mils of zinc remaining on the surface. The steel was completely free of rust or alloy layer staining. Given those facts, no maintenance was recommended. In 2015, in anticipation of the 80th anniversary of construction, it was again inspected. Close observation does show that there is still no rust or staining even after 80 years of service. This substation is the true test for hot-dip galvanized steel. It has been in working condition for almost 80 years and continues to perform as it was intended to with little to no maintenance.

Learn more about the Norris Dam at galvanizeit.org/norris-dam.