Innovative Monopole Tower System

Paul Migliore, AnemErgonics, LLC, [email protected] New Technology for Small Wind Turbine Monopole Tower Systems – Opportunities and Obstacles Small Wind Conference 2013: Stevens Point, Wisconsin 18-19 June 2013

Slide 1

New Technology for Small Wind Turbine Monopole Tower Systems — Opportunities and Obstacles —

Paul Migliore

AnemErgonics, LLC www.anemergonics.com


Slide 2

Development premise

Small wind turbines are a tough sell. Depressed economy discourages discretionary spending. Solar PV is a low cost renewable energy leader. Reliability and maintainability are customer concerns.

So we must seek cost reductions wherever they are available. Tower systems are a large part of the installed cost. Therefore, they are

a target of opportunity. AnemErgonics focuses on monopole towers.

SMarT Tower Systems for Small Wind Turbines Simple Modular Technology [U.S. Patent 8,161,698 and others pending]

U.S. DOE support in the form of a Small Business Innovation Grant and ongoing collaborations with NREL.


Slide 3

Concepts for tower system innovation

Innovations were aimed at the Skystream 3.7 but apply to small turbines in the ≤ 5 kW range. Monopole towers only

Not interested in guyed or lattice towers Others already doing this well

Technology components Fiberglass tower shafts Ductile cast iron components

No welds, better properties, lower cost Laser-cut and formed accessories.

No welds, simplicity, multiple vendors

Greatly simplified foundation logistics UPS-delivered Foundation Kit


Slide 4

Which would you rather construct?

AnemErgonics Foundation Fiber Reinforcement Only

(Pre-packaged Kits)

Mat + Pier Traditional Steel Reinforcement

(More than 200 Wire Ties)


Slide 5

Extensive testing enables innovation

Flexural Strength Tests Pullout Strength Tests

Credit: TEC Services Lawrenceville, GA


Slide 6

Payoff for foundation innovation

0%10%20%30%40%50%60%70%80%90%

100%

Relative Cost of SMarT Foundations

Traditional

SMarT

Rapid deployment Kits ship via FedEx, UPS, etc. Install multiple units in short time 1500 installed worldwide

Speedy completion after excavation 2-4 hours duration

Risk reduction Ensure parts alignment, placement

Time and cost savings But … scaling up is challenging

due to lack of experience with these innovations.


Slide 7

Which would you rather do?

Crane, High-Lift or Expensive Equipment

Simple Gin Pole for Tilt-Up/Down

Credit: West Wind Solar Electric


Slide 8

Extensive testing builds confidence

Tests at DOE / NREL National Wind Technology Center

20-year-life cycle structural tests Residual strength test to safety factor of 5 More than 50,000 hours of field tests 97 mph and -20o F


Slide 9

Payoff for tower innovation

« Half the weight of steel towers Tilt-up towers to 75’ height

» Twice the strength of steel towers Thick walls resist dents and buckling.

Any color Made in the USA Inexpensive tool kit

Gin pole and hinge plates

Potential cost savings But ….

Limited potential for scaling up Towers require electrical grounding Greater deflections require “education” of

user community


Slide 10

Obstacles to deployment (in order of difficulty)

Technical uncertainty What material properties to use for fiberglass towers? What deflections are acceptable? Extensive and expensive testing may be required.

Standards lag technology Fiber reinforced concrete is widely used in other applications, but guidelines are lacking for new purposes? There are no “recognized” standards for fiberglass towers. Test results may or may not be accepted by P.E.s. P.E.s are risk averse and not prone to “think outside the box.”

If it’s not invented here, it can’t be any good. Entrenchment

Vendor loyalty / familiarity Change is risky and potentially painful. Better the devil that I know than the devil that I don’t …


Slide 11

Obstacle – tower drag reduction

Tower drag can be more than half of the total tower and foundation load. Fiberglass exhibits significantly less drag than galvanized steel towers. Can we exploit this technical advantage? Not yet …..

Wind Tunnel Tests

TIA-222G Standard

NACA (Polhamus)


Slide 12

FAST predictions of tower top deflection match field experience fairly well.

At 60 mph a 60’ SMarT Tower deflects approximately 1.7% of its height.

At 120 mph, what is the point of establishing a deflection limit. Head for the tornado shelter!

Valid tower top deflection criteria Avoid blade strikes Avoid amplified loads Avoid controls interference

Challenges to setting a standard Uncertainty about requirements Inadequate analysis or testing Lack of experience

Inappropriate standard (TIA-222) 1% of tower height at 60 mph Total deflection or from mean? Why 60 mph? Why not cutout? Conforming towers have failed, so

what is the point of 1%?

Obstacle – tower deflection perceptions


Slide 13

What do these have in common?

AnemErgonics SMarT Towers National Wind Technology Center

Boeing 787 Dreamliner Credit: Long B. Nguyen www.pbase.com/longbachnguyen

• Both use composite materials that exhibit considerably more flexibility than traditional alternatives.

• Both systems improve cost effectiveness by 15-20%.

• Both have room for improvement.

http://www.pbase.com/longbachnguyen


Slide 14

Future possibilities

New materials Goal is 20% increase in fiberglass stiffness without sacrificing strength

or increasing cost.

More convenient, less expensive joining compounds Obtain exceptions to standards through testing

Fiber reinforced concrete for larger towers Lower drag coefficient for tower wind loads

Value engineering Always fruitful

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Innovative Monopole Tower System