Wind Power

Chester Ag Technology

Soon to be a common sight?

Wind power has been used for many years in Europe

This windmill was built in 1855, and has been used since then

Early wind power• Early wind power

was used by Europeans to turn grinding stones or to pump water

• They were quite complex in the control they had over the wind mills

Wind power• What is a wind turbine and how does

it work?

• A wind energy system – made up of wind turbines – transforms the kinetic energy of the wind into electrical energy that can be harnessed for practical use.

• There are two basic designs of wind turbines: vertical axis (or “egg beater” style) and horizontal axis (propeller style) machines.

Turbine systems include: • A rotor – or blades

– which convert the wind’s energy into rotational energy

Turbine systems include• A nacelle

(enclosure) containing a drive train, a generator, and usually a gearbox

This happens to be one of the Howard system’s nacelles

Turbine systems include• A tower to support

the rotor and drive train

Turbine systems include• Electronic

equipment such as controls, electric cables, ground support equipment, and interconnection equipment

Wind turbines• Wind turbine

towers are mostly tubular and made of steel; the blades are made of fiberglass-reinforced polyester or wood-epoxy.

• Wind turbines vary in size.

Wind turbine• The output of a

wind turbine depends on the turbine's size and the wind's speed through the rotor. Wind turbines being manufactured now have power ratings ranging from 250 watts to 3 megawatts (MW).

• What may seem like a small difference in wind speed can mean a large difference in available energy and in electricity produced, leading to a large difference in the cost of the electricity generated.

How does wind energy contribute to our electricity needs? • U.S. wind power

plants already serve more than 4.5 million average households with 12 million people. Wind power is capable of providing 20 percent of the country’s energy by 2030.

What are America’s current sources of electricity? • Coal, the largest

source of the leading greenhouse gas, carbon dioxide, is currently used to generate more than half of all the electricity generated in the United States.

• Other sources of electricity include natural gas, oil, nuclear, and hydropower.

Does wind power offer real environmental benefits? • Absolutely.• Wind requires no

mining, drilling, or transportation of fuel, and does not generate radioactive or other hazardous or polluting waste.

Does wind power offer real environmental benefits?

• Wind power offsets other, more polluting sources of energy. This is important because electricity generation is the largest industrial source of air pollution in the U.S. This is the largest turbine available

How does wind power benefit the economy?

• Wind power supplies affordable, inexhaustible energy to the economy. It also provides jobs and other sources of income.

• Best of all, wind powers the economy without causing pollution, generating hazardous waste, or depleting natural resources. Wind has no “hidden costs.”

• Wind energy depends on a free fuel source

Can wind energy help with rising natural gas prices?

• When a wind farm generates electricity in the U.S., the fuel it is most likely to displace is natural gas.

 Wind energy can provide a significant amount of the nation’s electricity.• The U.S.

Department of Energy estimates America’s wind energy potential to be much larger than total U.S. electricity consumption today.

• Tapping only a fraction of that potential would provide a significant part of America’s electricity supply.

Electric Transmission Lines

South Dakota Potential and Power Line

Wind turbines are extremely efficient.• Wind turbines are

actually very efficient.

• The energy payback time for wind is, in fact, similar to or better than that of conventional power plants.

Wind turbines are reliable and do not need back-up generation. • Because of the

electric grid’s inherent design, there is no need to back up every megawatt of wind energy with the equivalent amount of fossil fuel or dispatchable power.

Wind energy is affordable.• Wind power costs

are competitive with energy generated by conventional power plants, but the up-front costs of wind energy are often more expensive than that of some traditional power technologies.

• Wind receives tax credits and other economic benefits, though, that make it a viable choice for renewable energy generation.

Wind turbines do not generate much noise.• Wind turbines are

quiet. An operating modern wind farm at a distance of 750 to 1,000 feet is no louder than a kitchen refrigerator.

• The sound turbines produce is similar to a light whooshing or swishing sound

The wind industry makes protecting wildlife a priority.• Despite the

minimal impact wind development has on birds and bats in most areas, the industry takes potential impacts seriously.

• Avian studies are routinely conducted at wind sites before projects are proposed.

Dakota Wind Energy• Dakota Wind

Energy, LLC was formed to develop a series of wind energy projects based upon the concept of local, shared ownership.

• Dakota Wind Energy is located in rural northeast South Dakota.

Building a wind farm

One of the first steps in theconstruction process is siteclearing and building thegravel access roads. Accessroads are constructed fromexisting public roadways toeach turbine site to provideaccess for equipmentnecessary for construction,and to facilitate access to theturbine for ongoing operationand maintenance. Temporaryaccess roads are constructedwithin a corridor approximately40 feet wide.

Before gravel is installed topsoil isstockpiled, subsoil is compacted,and a geotextile matting is placed.Upon completion of construction,temporary access roads are convertedto smaller, permanent roadsapproximately 16 feet wide. Theportion being removed is clearedof gravel and fabric, decompacted,and topsoil restored.

A culvert can range inlength from 150 – 175 feet.This is necessary for thelarge component deliveries.

The width of the gravel road isapproximately 16 feet for theprimary travel path, but may beup to 40 feet wide during theconstruction phase to allow for thelarge cranes needed for turbineerection. All access roads arerestored to the 16 foot width afterconstruction is completed.

To erect the turbine, two differentcranes are needed. A smaller craneis used to install the turbine’s controlsystem and base and lower midtowersections. It is also used toassemble the rotor. A larger crane isused to install the upper mid-towerand top-tower sections, nacelleand rotor. Due to the size, weightand slow speed of this large crane,it cannot drive along public roads;therefore, it is necessary to createcross-country paths. The path usedis determined by several factorsincluding looking for the shortestdistance between turbines, use ofland already participating in theproject, significant changes in grade,and avoiding woodlands, wetlandsand waterways.

Topsoil is cleared andstockpiled, and the subsoilsare compacted. The cranepath area is restored oncethe turbines are standing.Landowners are compensatedfor lost crop opportunities in thearea used for the crane path.

The collector system is a series ofunderground electric cables that runfrom each turbine to the electricalsubstation. Typically, a series ofturbines will be interconnected tocreate a “circuit” – rather than havinga direct cable from each turbineto the substation. This is a drawing of a circuitthat connects 11 turbines andsends the electrical output to thesubstation via one undergroundcable system.

In this photo, there is a singlecircuit being installed in a twofoot-wide trench. When multiplecircuits are installed in adjacenttrenches, there must be a fivefoot-wide separation betweeneach circuit. The minimumburied depth is four feet.

The first steps in constructingthe foundation is to remove andstockpile topsoil and subsoils.These soils are stockpiledseparately. Upon completion offoundation construction, the soilsare replaced in the proper strata.

Foundations are constructedby excavating a hole,placing reinforcing steeland pouring approximately325 yards of concrete into theexcavation. Each foundationis approximately 55 feet wideand 8 feet deep in the center.

Topsoil and subsoilfrom the excavation isstockpiled in a semicirclearound the foundation.The next step is to replacethe subsoil and then thetopsoil over the concretefoundation. Only the verycenter of the foundationremains above the soilsurface when grading iscomplete.

A backfilled foundation priorto topsoil replacement andcrane pad installation.

After the foundation construction iscomplete and the area backfilled, a cranepad is constructed to allow for turbineerection. The area is approximately 55 x 80feet and will remain after construction forroutine maintenance activities.

crane pad area

• There are four main parts of a wind turbine:

• The foundation(base),the tower, the nacelle, and the rotor (hub and blades assembly).

• The rotor converts the energy of the wind into rotational motion.

• The foundation acts as an anchor that supports the entire assembly.

• The nacelle contains the electric generator and other components that convert the mechanical rotation of the rotor into electricity.

• The tower supports the nacelle and rotor.

For the Blue Sky Green Fieldsite, the tower sections wereoff-loaded at the Port of Green Bayand transported by truck to thesite. Each truck transported onetower section - approximately74 feet long.

The first componentsdelivered and erected arethe base and mid-section ofthe tower. When completed,each turbine consists of fourtower sections.

PowerModule

It takes approximatelyseven hours to set thefirst two tower sections.

The base and mid-section, asseen here, stand approximately105 feet. The total height of theturbines at Blue Sky Green Fieldfrom the base to the tip of theblade is 397 feet.

The nacelle is theenclosure at the top ofthe tower that containsthe drive shaft, gearbox,generator, electroniccontrols and associatedequipment. The nacelle isreached by a ladder thatruns inside the tower sotechnicians can accessthe turbine components formaintenance and repair.

The yaw deck allowsthe rotor and nacelle toalign with the wind.

The yaw deck is ableto turn three completerevolutions beforelocking to ensure thecables are not twisted. Itwill then reset itself.

The blades are connectedto a central cone called thehub, which is connected toa shaft that passes into thenacelle.

Turbine blades haveaerodynamic wings thatcreate lift and rotation ofthe rotor as the wind blowsacross them. Each turbineblade at Blue Sky GreenField measures 134 feet.The rotor assembly weighsapproximately 47 tons.

Restored site after activation

The area around the turbine isreturned to the landowner forplanting. We ask that a distanceof 15 feet be maintained from thefoundation of the towers to protectthe equipment. Directly under thisarea, only 18-24 inches belowthe surface, are the concretefoundations and grounding cablesfor the turbines. For safety, gravel isplaced in this area as a reminder ofthe underground infrastructure.

Homeowner Wind Power• There is a lot of

interest in small, homeowner wind turbines

• There has been experimenting with this for a long time

An example is the brand new Swift Wind Turbine

• Swift is a rooftop mounted wind turbine that is quiet.

• The outer ring on Swift acts as a diffuser as the wind travels down the blades and is dispersed along the outer ring, therefore eliminating the noise and keeping the turbine quiet.

• What is the average cost to install a Swift Wind Turbine?

•Swift has an estimated installed cost of about $10,000 – $12,000. Depending on the installed price, cost of electricity, average wind speed, and rebates available the Swift Wind Turbine can pay for itself in as little as 3 years.

Swift Wind Turbines

• How much electricity can I expect from my Swift Wind Turbine?

•Swift will generate about 2000 kWh in a good wind location. This is about 20% of an average homes use. Multiple units can be used at one location to supplement commercial and industrial use.

Other wind power ideas• Offshore wind power

– Strongest winds are here– Can build much taller

• Vertical axis turbines– May be more efficient

• Road turbines– Use the power of traffic to turn turbine

Offshore

Vertical Axis

Highway traffic turbines

Infrastructure is slowing us down

Large transformers 175 tons

Power lines

The End