Towers

Why worry too much about the tower? Would you put a solar collector in the shade? Wind is the fuel! Remember, 30’ above anything w/in 500’ Measure from the bottom of the swept area

Costs Turbine grabs our attention in a wind system, but... –The Balance of System (BOS) can easily cost more than the turbine and –The tower can be 2-10 times as much as the turbine

Consider the work of a workshop Most expect to mess with turbine most of the time, There is much more to do than turbine such as... –Tower work Rope work, winch work, assembly, anchors, transit work, tightening cable clamps (1-4 days) –Electrical work Pulling wire laying conduit diggin ditches ((1-3) –Actual turbine work Assemble, mount to tower (few hours – 1 day)

3 Basic Tower Types Tilt-up –Easy maintenance, no climbing Fixed, guyed –Very common, climbable Freestanding –Costly but attractive and climbable

Small Wind Turbine Towers Fixed Guyed Tower Tilt-Up Tower Self-Supporting Tower

Fixed Guyed Tower Build on ground Tilt-Up with crane (3) guy wire anchors, climbing, crane

Fixed Guy Towers Lifted once and does not tilt down –Can have 3 guy wires Maintenance is done by climbing Come in different configurations Lifted in one of two ways –With gin pole, but in a different manner –With a crane

Fixed Guy Towers Do not require open area of a tilt-up but still need open lanes for the guy wires Guy radius is 50% to 80% of tower height Costs are similar to tilt-up You have ore options for guyed towers because do not need as much open area

Tilt-Up Guyed Tower Build on ground Tilt-Up with winch or grip- hoist (4) guys wire anchors, maintenance on ground, economical

Careful with heavy turbines and tilt up towers… Here is the 250lb AWP freakin out the tower crew at Beech

Tilt-up towers All maintenance from ground Come in heights up to 130 feet and different sizes (to accommodate turbine size and thrust) All tilt-up have 4 guy wires 3 concrete pads with the winch attached to gin pole and 4 th pad

Tilt-up Gin Pole Gin-pole attaches at 90° angle –Gin pole is typically 75% to 100% of the guy radius Gin-pole is a lever that allows you to lift tower which pivots at bottom Can raise or lower with truck, tractor, winch, come-along or grip hoist –Remote location requires winch or grip hoist

Tilt-up Blues Big diamond shaped footprint –Clear of trees for up 150’x150’ They can be dropped, tow vehicles can slip For those who do not mind climbing, a tilt-up tower can be less convenient Skill must be acquired for tilting towers Miss the beautiful vistas!

Self Supporting Towers Build on ground Raise with tractor or crane No guy wires, requires climbing or crane

Free Standing Towers No guy wires No tilting Modest space requirement Involves lots of steel and concrete so more expensive Higher cost of materials, labor, excavation, concrete forms, and rebar

Free Standing Towers 2 Basic Forms –Three-legged Eiffel style –Monopole, slender (often very expensive and out of budget for small scale wind owners) Free standing tower will cost at least 1/3 to 1/5 more

Anchors Screw-in AugerArrowheadRock anchors

Details Follow manufacturer’s recommendations for anchors Never saddle a dead horse Saddle, live wire U-bolt, dead wire Avoid sharp guy wire bends

Homebrew Towers Be careful. Engineer it properly Build it plenty strong In the end you may need an engineer’s stamp for permits so just buy a professionally designed tower.

Choosing a Tower Turbine manufacturer will tell you what tower size is necessary to hold your turbine Remember that trees grow so plan for mature tree size Is there space for a tilt-up? Is someone going to climb the tower that you know? Ask neighbors about aesthetic concerns

Choosing a Tower Take time to go look at tower installations to know for yourself what you are getting into Don’t make your tower too short Most common mistake in wind system design If you lack experience seek professional advice