Wind energy tech 2015

Lecture 11
Wind 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 - 1941-45
1.25 mw @30 mph

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

Home Built Machines
Open Source Design at Otherpower.com
Hugh Piggot
Video at www.mum.edu
UNI CEEE has video of student wind project

Northfield Minnesota - St Olaf and Carleton College

Power delivered (watts) = Cp x ½ x d x A x V3
where
Cp = the power efficiency of the rotor, explained on
next slides
A = swept area of a turbine
= pi x r2
(pi = 3.14) ; r = radius of swept area, i.e.
blade length, in meters
d = density of air = 1.225 kg/cubic meter
V = wind speed

These are equal amounts of energy:
1 hour of wind at 20 mph
8 hours of wind at 10 mph
64 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

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 strategy
changing blade pitch
rotating whole machine away from wind
Type of high wind shut off
Electric “brake”
Mechanical brake
Manually rotate machine out of wind
Type of generator
DC, AC, Permanent Magnet,
How does it automatically face the wind (yaw control)?
Upwind vs downwind

System Design Considerations
Grid-tie vs Off-grid
If grid tie:
Batteries vs Grid-tie only
If off-grid:
System voltage
Battery capacity
Inverter selection
Monitoring, metering
Distance from wind gen to power use
Wire sizes

Tower Considerations
Height: Taller is Better
Tilt down vs Fixed
Guyed vs Stand-Alone
Tubular 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

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

Calculating Annual Output
Use Iowa Energy Center Web Site
OR
Collect Wind Data
Correct for anemometer height
Histogram of wind speeds
Wind speed and hours = or exceeded
Spreadsheet
Short Cut Capacity Factor method

Costs
How much energy do you need?
Typical home uses 800 kwh/mo
Abundance Ecovillage homes use 100 kwh/mo
Small system
cabin or boat, 10-20 kwh/month
4 foot diameter rotor, 300-400 watts $1000-2000
Ex. SW Windpower Air X, Air Breeze (100,000 sold)

Costs cont’d
Medium system
Grid tie or off-grid: 100-400 kwh
12 - 18 foot blade diameter
2-5 kw
Ex Sw Windpower Skystream
12 foot blade dia 1.8 kw (1800 watts)
$12,000 - $20,000 Large System:
Large System
Grid tie mostly: 500-2000 kwh/mo
18-30 foot blade diameter
5-20 kw
Ex 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……

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.

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 0.00
2 0.00
3 0.14
4 0.43
5 0.88
6 1.51
7 2.35
8 3.43
9 4.80
10 6.42
11 8.21
12 10.02
13 11.37
14 11.76
15 12.06
16 12.14
17 12.15
18 12.10
19 11.92
20 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 kw
Bergey XL 1 = 8.2 ft (53 sq ft), 1.0 kw
Whisper H40 = 7 ft (38 sq ft), .9 kw

(k/c)*(v/c)k-1
exp[-(v/c)k]
K=shape parameter, c = scale parameter
Weibull Probability Distribution Function
Rayleigh = 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 mph
Wind odometers
Raleigh Statistics, Average Wind Speed and Average Power

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

Energy Cost From New, Large Turbine
New 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/yr
Annual O&M @ 1.5-2.5% of turbine = $18,000-$30,000/yr
Total direct cost = $149,000-$183,000/yr
Direct cost per unit energy produced = 2.9-3.9 ¢/kWh
Long-distance transmission cost = 0-0.8 ¢/kWh
Total 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 Total
cost 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 8.5-16
New nat gas 3.3-3.6 0.7-1.1 0.4-2 0.5-1.1 4.9-7.8
New wind 2.9-4.7 <0.1 <0.1 <0.1 2.9-5.0

Impacts of Wind vs. Fossil-/Biofuels
U.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/yr
Extrapolated 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.
Hydrogen
Storage
Grid
H2 Gas
+
-
V
Water
Supply
H2 Trucking H2 Pipeline
O2 Gas
Peak Shaving
ICE/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 TechnicallyWind-Hydrogen Forms a Green Energy Cycle and is Technically
FeasibleFeasible

Hydrogen
Buffer Storage
O2 Gas
200MW
4500 kg/hr, 25 bar
350bar
10” Diameter, 25 bar
$1MM /mile
η ~85% (1000 miles)
200 MW
$1000/kW
η ~75%
4500 kg (150 MWh)
$100/kWh
HH22 Production with Pipeline Delivery (ND-Chicago)Production with Pipeline Delivery (ND-Chicago)
North Dakota - Chicago
1000 miles
500 MW
$1000/kW
util. 40%
Water ConsumptionWater Consumption
324,000 gal/day324,000 gal/day
HH22 production:production:
91,809 kg/day91,809 kg/day
@ $8.9/kg@ $8.9/kg
100 miles
1 MW 1 MW
6 MW
$1000/kW
η ~80%
North Dakota-Chicago: 1000 miles
Hydrogen pipeline
3gal/kgH2
NOTE: Assuming pumps along pipeline are powered by H2

Wind power boosting employment worldwide. 35,000 jobs created in Germany
Contributed 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 abroad
Vestas 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.

Solar and Wind
Resources
Annual Solar kwh per kw: 1534
Wind 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 - Greco
Excerpts and interviews available at www.biggreensummer.com (look for Iowa
Mayors Reader)

Resources and Contact Info
www.professorlonniegamble.com
www.biggreensummer.com
www.abundance-ecovillage.com
www.renewfairfield.com
www.mum.edu
lonniegamble@yahoo.com

Berwynn, Illinois Laundry
Solar saves $2000/Month

Rotor Tip Speed
Example: 300 foot diameter, 20 rpm
Distance traveled by tip in one rotation:
Pi*D = 300*3.14 = 942 feet
Distance traveled per minute:
942*20 = 18840 feet
Miles per minute:
18840/60 = 3.6 miles per minute
Miles 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
Small-scale Applications
Farms, Homes, Businesses
Off-Grid Water
Pumping with Wind
• Produces ~ 2,000
kWh/yr
• Offsets ~ 1.5 tons
•
Supplies
water
for
120
head
of
cattle
• 1 kW,
9-ft
rotor,

Small-scale Applications
Farms, Homes, Businesses
Offsetting
All Utility Power
•“Net metering” utility
power
• 10 kW, 23-ft rotor
diameter, 100-ft
Selling Power
Back to Utility
• Produces ~120,000
kWh/yr
• Offsets ~ 91 tons
• Excess
power
sold to
utility
• 50 kW,
49-ft
rotor,
90-ft
tower

Wind energy tech 2015

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