Lecture 11Wind Energy Overview

E-101 - Energy and Sustainability Professor Lonnie Gamble

Sustainable Living Department Maharishi University of Management

This presentation was prepared on solar powered computers

Grandpa’s Knob Vt - 1941-451.25 mw @30 mph

1957 - German stgw-34

Germany, 1942

Hutter, Germany, 1958 10kwInstalled on oil rig in gulf of mexico - more reliable and cheaper than diesel

Source Diversity

MUM Student Wind Turbine

Home Built Machines

Open Source Design at Otherpower.comHugh PiggotVideo at www.mum.eduUNI CEEE has video of student wind project

Wind Turbine Components

Northfield Minnesota - St Olaf and Carleton College

Power delivered (watts) = Cp x ½ x d x A x V3

whereCp = the power efficiency of the rotor, explained on next slidesA = swept area of a turbine = pi x r2 (pi = 3.14) ; r = radius of swept area, i.e. blade length, in metersd = density of air = 1.225 kg/cubic meter V = wind speed

These are equal amounts of energy:

1 hour of wind at 20 mph8 hours of wind at 10 mph64 hours of wind at 5 mph

Double the wind speed = 8 times the power

Example

The wind generator for the SL Center is a Bergey XL 10, with a 23 foot (7 meter) rotor with a Cp of .25. What is the power output of the generator in a 20 mph (9 m/s) wind?

P = Cp x .5 x density x A x V3

= .25 x .5 x 1.223 x (pi x 3.52) x 93

= 4228 watts

Typical Cp = .15-.35

Bergey Power Curve

1 meter per second = 2.24 miles per hour

Maximum Efficiency of Wind Turbines:Betz Law (1919)

Maximum power: downstream wind speed = 1/3 of upstream wind speed

Wind Turbine Design Considerations

High wind survival strategychanging blade pitchrotating whole machine away from wind

Type of high wind shut offElectric “brake”Mechanical brakeManually rotate machine out of wind

Type of generatorDC, AC, Permanent Magnet,

How does it automatically face the wind (yaw control)?Upwind vs downwind

System Design Considerations

Grid-tie vs Off-gridIf grid tie:

Batteries vs Grid-tie only If off-grid:

System voltage Battery capacityInverter selectionMonitoring, meteringDistance from wind gen to power useWire sizes

Tower Considerations

Height: Taller is BetterTilt down vs FixedGuyed vs Stand-AloneTubular vs Lattice

Tower Height: minimum 20 feet taller than anything in a 300 foot radius - the taller the better

Obstructions, Turbulence

Distance to where the power will be used, cost for utility connection

Neighbors, NIMBYs

Utility interconnection policies

Wind Turbine Siting Considerations

Skystream 1800

• 12 foot diameter blades• 1800 watts in 20 mph wind• Inverter and controls built in to tower top

nacelle• Blades turn downwind of tower• 400 kwh/ month in

Installation sequence

Turbine spacing in wind farms

How to Calculate Annual Energy Production

DO NOT USE AVERAGE ANNUAL WIND SEED

• Energy related to V3

• 103 = 1000• 133 = 2197• Ex: Vhr 1 Vhr 2 Vhr 3 Vavg E

10 10 10 10 1000 x 3= 3000 kwh

30 0 0 10 27000 + 0+ 0 = 27000 kwh

Calculating Annual OutputUse Iowa Energy Center Web Site

ORCollect Wind Data

Correct for anemometer heightHistogram of wind speeds

Wind speed and hours = or exceededSpreadsheet

Short Cut Capacity Factor method

Costs

How much energy do you need?Typical home uses 800 kwh/moAbundance Ecovillage homes use 100 kwh/mo

Small systemcabin or boat, 10-20 kwh/month4 foot diameter rotor, 300-400 watts $1000-2000Ex. SW Windpower Air X, Air Breeze (100,000 sold)

Costs cont’dMedium systemGrid tie or off-grid: 100-400 kwh 12 - 18 foot blade diameter2-5 kwEx Sw Windpower Skystream12 foot blade dia 1.8 kw (1800 watts)$12,000 - $20,000 Large System:

Large SystemGrid tie mostly: 500-2000 kwh/mo18-30 foot blade diameter5-20 kwEx Bergey Excel 22 foot blade dia, 10 kw$35,000

What about negative impacts of Wind?

• Aesthetics?• Noise?• Land use conflicts?• Bird mortality?

WIND TURBINES KILL BIRDS

• All avian studies at wind farm sites show that bird kills per turbine average two to five per year or less, with the exception of a single 3-turbine plant in Tennessee that has recorded eight per turbine per year. These include sites passed by millions of migrating birds each year. At a few sites, no kills have been found at all.

•cats (1 BILLION per year) •buildings (100 million to 1 BILLION per year)•hunters (100 million per year)• vehicles (60 million to 80 million per year)• communications towers (10 million to 40 million per year)• pesticides (67 million per year)• power lines (10,000 to 174 million per year)

However……

Causes of Bird Mortality

Controlling Bird Loss?

Although measures should be taken to reduce bird mortality, in siting and operating wind farms, the National Audubon Society strongly supports wind power development as a means to mitigate GHG emissions and climate change, a far greater threat to the world’s bird populations.

Wind turbine scams

EX Find Average Wind Speed and Ave power in the wind (w/sq meter)

V avg = SUM(V x Fraction of hours at V)= 7

V3 avg = SUM(V3 x Fraction of hours at V)= 653.24

P = ½ x (density) x (V3)avg

= .5 x 1.225 x 653.24 = 400 w/sq m

Ex: How much energy is there between 4 and 8 mph compared to between 15 and 19 mph?

Bergey XL 10 with wind distribution on previous page

Wind Speed Bin (m/s)

Power (kW) at sea level

1 0.002 0.003 0.144 0.435 0.886 1.517 2.358 3.439 4.8010 6.4211 8.2112 10.0213 11.3714 11.7615 12.0616 12.1417 12.1518 12.1019 11.9220 11.44

Wind Velocity m/s Hours Power (kw) Energy (kwh)

4 1.8 500 0 0

5 2.2 600 0.05 30

6 2.7 650 0.13 84.5

7 3.1 750 0.2 150

8 3.6 800 0.3 240

Sum 504.5

15 6.7 900 2 1800

16 7.1 870 2.6 2262

17 7.6 850 2.9 2465

18 8.0 805 3.43 2761.15

19 8.5 750 4.1 3075

Sum 12363.15

24 times the energy at 15-19 mph compared to 4-8 mph

Proven = 11.48 ft (104 sq ft), 2.5 kwBergey XL 1 = 8.2 ft (53 sq ft), 1.0 kwWhisper H40 = 7 ft (38 sq ft), .9 kw

Wind speed frequency chart

(k/c)*(v/c)k-1 exp[-(v/c)k]

K=shape parameter, c = scale parameter

Weibull Probability Distribution FunctionRayleigh = Weibull w/ k=2

Rayleigh distribution is a special kind of Weibull graph with k=2

If the wind probability density function has a Raleigh distribution, then:

PAVERAGE = 1.91 x ½ x density x V3 AVERAGE = watts/ sq meter

Ex: 7 m/s (15.7 mph,) average wind speed at 125 feet, what is the average power in the wind, assuming a Raleigh pdf?

1.91 x .5 x 1.223 x 73 = 401 watts/ sq meter

1 m/s = 2.24 mphWind odometers

Raleigh Statistics, Average Wind Speed and Average Power

Capacity Factor 25-30%40% would be very good

Energy Cost From New, Large TurbineNew 1500 kW turbine, 77-m diameter blade, 7-7.5 m/s annual winds

Energy produced per year: = 4.68-5.24 x 106 kWh/yr

Cost of turbine+installation+land+financing+roads+consultancy = $1000/kW

Amortize over 20 years @6-8% = $131,000-153,000/yrAnnual O&M @ 1.5-2.5% of turbine = $18,000-$30,000/yrTotal direct cost = $149,000-$183,000/yr

Direct cost per unit energy produced = 2.9-3.9 ¢/kWhLong-distance transmission cost = 0-0.8 ¢/kWhTotal cost: = 2.9-4.7 ¢/kWh

Direct and Externality Costs of Three Energy Sources

Sources:DOE Office of Fossil Energy (2001) Science 293, 1438 (2001) Derived From UNEP (2001) European Commission (1995) Atmos. Environ. 35, 4763 (2001)

Direct Global Particle Other Totalcost warming health environ. cost(¢/kWh) cost cost cost (¢/kWh)

(¢/kWh) (¢/kWh) (¢/kWh)

New coal 3.5-4 0.4-1 3-8 1.6-3.3 8.5-16New nat gas 3.3-3.6 0.7-1.1 0.4-2 0.5-1.1 4.9-7.8New wind 2.9-4.7 <0.1 <0.1 <0.1 2.9-5.0

Impacts of Wind vs. Fossil-/BiofuelsU.S. bird deaths from 7000 turbines 10,000-40,000/yr (!)U.S. bird deaths from transmission towers: 50 million/yr (!)Worldwide bird deaths from avian flu: 200 million/yr (%)

Extrapolated bird deaths with 860,000 turbines: 1.2 million/yrExtrapolated bird deaths with 5,000,000 turbines: 7.1 million/yr

Premature U.S. deaths fossil-/biofuel pollution: 80,000-137,000/yr (*)U.S. respiratory illness fossil-/biofuels: 63-105 million/yr (*)U.S. asthma fossil-/biofuels: 6-14 million/yr (*)

The effect of wind turbines on birds will always be trivial relative to the benefit of reducing fossil-biofuels on human and animal illness.

(!) Bird Conservancy (April 2006); (%) San Jose Mercury News (April 2006)(*) McCubbin and Delucchi (1999)

Dakotas to Chicago Hydrogen

4000 mw wind on 350 sq miles in North Dakota(2% of potential in N Dakota)

Hydrogen Pipeline or HVDC

Electrolyzer

- Water purification - Regulators- Gas dryer- Shutdown Switch- etc.

HydrogenStorage

Grid

H2 Gas

+

-

V

Water Supply

H2 Trucking H2 Pipeline

O2 Gas

Peak ShavingICE/Fuel Cell

Power Conditioner-Grid Interconnector-Max Power Tracker-AC/DC converter-Power Supply Switch -etc.

Control

Systems

Local H2 Use

Wind-Hydrogen System ConceptWind-Hydrogen System Concept

Wind-Hydrogen Forms a Green Energy Cycle and is Technically Wind-Hydrogen Forms a Green Energy Cycle and is Technically FeasibleFeasible

HydrogenBuffer Storage

O2 Gas

200 MW

4500 kg/hr, 25 bar

350 bar

10” Diameter, 25 bar$1MM /mile ~85% (1000 miles)

200 MW$1000/kW ~75%

4500 kg (150 MWh)$100/kWh

HH22 Production with Pipeline Delivery (ND-Chicago) Production with Pipeline Delivery (ND-Chicago)

North Dakota - Chicago1000 miles

500 MW$1000/kWutil. 40%

Water ConsumptionWater Consumption324,000 gal/day324,000 gal/day

HH22 production: production:91,809 kg/day91,809 kg/day

@ $8.9/kg@ $8.9/kg

100 miles1 MW 1 MW

6 MW$1000/kW ~80%

North Dakota-Chicago: 1000 milesHydrogen pipeline

3 gal/kg H2

NOTE: Assuming pumps along pipeline are powered by H2

Wind power boosting employment worldwide. 35,000 jobs created in GermanyContributed by Ferhat on Monday, April 15 @ 08:06:50 PDT Topic: Old News Osnabrück/Hanover. The rapid development of wind power is increasingly stimulating the jobs market, particularly in economically weak regions. By the end of last year, the sector employed more than 35,000 people in Germany – at manufacturing companies, component suppliers, project developing businesses or operators. "This year we expect at least 3,000 new jobs in the wind industry," said Andreas Eichler, spokesman for the company advisory board of the German Wind Energy Association (BWE) at the opening of the Hanover Trade Fair 2002 today. Many turbine manufacturers and component suppliers expanded existing production capacities and built new factories last year. For instance, German market leader Enercon GmbH inaugurated a new rotor blade factory in Magdeburg-Rothensee, Nordex AG also launched a new blade factory in Rostock and Pfleiderer Wind Energy GmbH started up a new wind turbine assembly plant in Coswig near Dresden (Saxony). More production facilities are under construction in Germany and abroadVestas Deutschland GmbH, for example, is building a rotor blade plant in Lauchhammer in southern Brandenburg. The new factory will result in 450 new jobs – reason enough for German chancellor Gerhard Schröder to visit at the end of May. The Vestas parent company, Vestas Wind Systems A/S of Denmark, will build a new wind turbine works in Portland, Oregon (USA), this year, creating 1,000 new jobs for the region. "It goes without saying that the companies are making these investments because worldwide prospects for wind power growth are so bright,” says Eichler. Last year saw a wind energy growth record in Germany, with 2,659 megawatts (MW) being newly installed, for a turnover of €3.5 billion. Experts forecast similarly dynamic growth for this year, estimating an additional 2,500 – 3,000 MW, which will see Germany continuing to lead the world pack in terms of wind power development.

More than 10 major European banks and more than 20 European utilities have invested in wind energy as have individuals and companies.  In Denmark over 100,000 individuals have made their own investments in wind.

The wind industry is also a major employer.  A recent study by the Danish Wind Turbine Manufacturers Association concludes that the Danish wind industry alone employs 8,500 Danes and has created a further 4,000 jobs outside Denmark.  The Danish wind industry is now a larger employer than the Danish fishing industry.  Total employment within the wind industry in Europe as a whole is estimated to exceed 20,000 jobs.

An analysis by the National Wind Technology Center indicates that conditions suitable for supplying

wind energy exist over 6 percent of the contiguous United States. Wind, if fully exploited, could provide

annually more than one and one half times the amount of electricity used in the United States today.

At present, wind only provides a tiny fraction of apercent of US electrical energy

In Denmark, where the government strongly supports such research, 5 percent of the country's

electricity comes from wind power, with some areas generating as much as 25 percent of their electricity from wind. Uneven support for research is one

reason the United States has been slow to increase the use of wind energy.

To provide 20% of the nation's electricity, only about 0.6% of the land of the lower 48 states would have to be

developed with wind turbines. Furthermore, less than 5% of this land would be occupied by wind turbines,

electrical equipment, and access roads. Most existing land use, such as farming and ranching, could remain as it is now.

Moreover, the estimates show that a group of 12 states in the midsection of the country have enough wind energy potential to produce nearly four times the amount of electricity consumed by

the nation in 1990.

.  In our state of South Dakota, the AWEA estimates that 117 GW (yes, gigawatts) of

windpower potential exists, and yet we currently have an installed wind generation

capacity of zero.

North Dakota alone has enough potential energy from windy areas of

class 4 and higher to supply 36% of the total 1990 electricity consumption of

the 48 contiguous states.

Darriues Patent

Solar and Wind Resources

Annual Solar kwh per kw: 1534Wind kwh/sq ft swept area: 59

Monthly Wind Vs Solar

0

1000

2000

3000

4000

Month

kWH Output

Solar (19 kW peak) 2060 2060 2949 2646 2873 2892 2967 2476 2741 2665 1455 1361

Wind (18 kW, 25 ft

rotor)

3049 2708 3321 3389 2638 1917 1504 1313 1614 2075 2675 2961

Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec

Sustainable Design Reading Recommendations

• Ecocities - Richard Register• Natural Capitalism- Hawken, Lovins, Lovins• Cradle To Cradle - William Mcdonough

– Film: The next industrial revolution• The Nature of Design - David Orr• Permaculture: A Designers Manual - Mollison • Deep Economy - The wealth of Communities and a Durable Future - Mckibben• Short Circuit - Richard Douthwaite • Ecological Economics - Herman Daley• Community Energy - Greg Pahl• Reinventing Money - GrecoExcerpts and interviews available at www.biggreensummer.com (look for Iowa

Mayors Reader)

Resources and Contact Info

www.professorlonniegamble.comwww.biggreensummer.com

www.abundance-ecovillage.comwww.renewfairfield.com

www.mum.edu

lonniegamble@yahoo.com

Solar and Wind Resources

Annual Solar kwh per kw: 1534Wind kwh/sq ft swept area: 59

Monthly Wind Vs Solar

0

1000

2000

3000

4000

Month

kWH Output

Solar (19 kW peak) 2060 2060 2949 2646 2873 2892 2967 2476 2741 2665 1455 1361

Wind (18 kW, 25 ft

rotor)

3049 2708 3321 3389 2638 1917 1504 1313 1614 2075 2675 2961

Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec

Berwynn, Illinois Laundry Solar saves $2000/Month

Rotor Tip Speed

Example: 300 foot diameter, 20 rpmDistance traveled by tip in one rotation:Pi*D = 300*3.14 = 942 feetDistance traveled per minute:942*20 = 18840 feetMiles per minute:18840/60 = 3.6 miles per minuteMiles per hour:3.6*60 = 216 miles per hour

Tip Speed Ratio

• Tip Speed Ratio (TSR) = Rotor Tip Speed/ Wind Speed

• Example: 200 mph tip speed, 20 mph wind speed

• TSR = 200/20 = 10

The components for fixed speed generation are cheaper than for variable speed, so this method was, and still is, used, despite the loss of approximately 20% of energy production by not having variable speed with constant .

Supplementing Grid Power

• Connected to utility grid through house/farm wiring• 3 kW, 15-ft rotor, 23-ft tower*• Produces ~ 5,000 kWh/yr• Offsets ~ 3.8 tons CO2/yr• Costs ~ $10,000

* due to zoning restrictions (not recommended)

Small-scale Applications Farms, Homes, Businesses

Off-Grid Water Pumping with Wind

• Produces ~ 2,000 kWh/yr• Offsets ~ 1.5 tons CO2/yr• Costs ~ $4,000 installed

• Supplies water for 120 head of cattle • 1 kW, 9-ft rotor, 30-ft tower

Small-scale Applications Farms, Homes, Businesses Offsetting

All Utility Power

•“Net metering” utility power• 10 kW, 23-ft rotor diameter, 100-ft tower• Produces ~ 15,000 kWh/yr• Offsets ~ 14 tons CO2/yr• Costs ~ $35,000

Selling Power Back to Utility

• Produces ~120,000 kWh/yr• Offsets ~ 91 tons CO2/yr• Costs ~ $150,000

• Excess power sold to utility • 50 kW, 49-ft rotor, 90-ft tower