2012
NIPSCO Energy Symposium
October 10, 2012
Renewable Energy
Tracy Hall, LEED AP®,
NABCEP® Certified Solar PV Installer
What is Renewable Energy?
• renewable energy
Any naturally occurring, theoretically inexhaustible
source of energy, such as biomass, solar, wind, tidal,
wave, and hydroelectric power, that is not derived
from fossil or nuclear fuel.
• Biomass
• Wind
• Solar
Source: Dictionary.com
What is renewable energy?
Source: Obscure...
Conversions
•
•
•
•
•
•
•
•
•
•
1,000 watts = 1 kilowatt (kW)
1,000 kW = 1 megawatt (MW)
1,000 watt-hours = 1 kilowatt-hour (kWh)
1,000 kWh = 1 megawatt-hour (MWh)
1,000 MWh = 1 gigawatt-hour (GWh)
1 mile per hour = 0.447 meters per second (mps)
1 mps = 2.24 mph
1 meter = 3.28 feet - 1 foot = 0.305 meter
1 square meter (m2) = 10.76 square feet (ft2)
1 ft2 = 0.093 m2
5
Pros and Cons
•
•
•
•
•
•
•
Good for environment
Good for economy
Security
Clean, Non-Polluting
Free or cheap fuel
Infinite supply of fuel
Incentives and some grants available to help
reduce costs
Pros and Cons (continued)
• Not In My Backyard Yard (it’s ugly, noisy, kills
birds, etc…)
• Expensive initial investment
• Incentives are sporadic, lacking, or
non-existent
•
•
•
•
Resources may be intermittent
May produce an unusable voltage
Energy storage
Finding competent installers/maintenance
The actual costs of traditional energy
fuels may not be accurately reflected
in the price we pay for them…
Source: Fuelfix.com
Source: eia.gov
Biomass
• Plant material, vegetation, or agricultural
waste used as a fuel or energy source.
• includes transportation fuels such as biodiesel
and alcohol fuels like ethanol and methanol,
methane gas from garbage and human or
livestock waste.
C
Biomass – What is it?
• Organic materials, such as . .
- Wood
- Wood chips
- Yard waste
- Paper waste
- Agricultural crops
- Agricultural crop waste
- Animal waste
- Wild grasses
- Other wild plant material
- Municipal wastes
- Human waste?
- Cultivated algae
- etc.
12
• Are converted into fuel by . . .
- Mechanical means
- Fermentation
- Digestion
- Pyrolysis
• To produce fuels such as . .
- Direct combustion feed stock
- Ethanol
- Bio-diesel
- Hydrogen
Source: James T Gill, Wilbur Wright College
C
Biomass – The Current Bio-fuels industry
(a schematic diagram)
Biomass Sources
Processes
Products
Hydrolysis
The Benefits
Sugars and
Lignin
Acids, enzymes
Gasification
Synthesis Gas
High heat, low
oxygen
Feedstock
production,
collection,
Digestion
handling &
preparation
Pyrolysis
Bio-gas
Bacteria
Bio-Oil
Catalysis, heat,
pressure
Carbon-Rich
Chains
Extraction
Mechanical,
chemical
Mechanical Separation
13
Plant
Products
Slide courtesy of Jim Spaeth USDOE
Fuels:
Ethanol
Renewable Diesel
Hydrogen
Power:
Electricity
Heat
Chemicals
Plastics
Solvents
Chemical
Intermediates
Phenolics
Adhesives
Furfural
Fatty acids
Acetic Acid
Carbon black
Paints
Dyes, Pigments, Ink
Detergents
Food Feed Fiber!
Livestock
Human
C
Biomass – The Current Bio-fuels Industry
(a more detailed schematic diagram)
Luckily, Jim Spaeth
at the U.S. Department of Energy office of Energy
Efficiency and Renewable Energy (known as EE/RE)
assembled a Flow Diagram that helps explain the
complexity of the new world of Biomass Energy.
Let’s take a few moments to study it so we might better
understand “Bio-fuels.”
If you gain a complete understanding of this diagram,
chances of employment will be . . . great!
14
Slide courtesy of Jim Spaeth USDOE
C
Biomass – Energy Conversion
Understanding bio-mass may be simpler than it may first seem!
1 • Direct combustion of biomass . . .
• Convenient fuel commodities from biomass
2
- Liquid & gas extraction . . .
3
- Capture from microbial decomposition . .
4
- Capture by pyrolytic decomposition . . .
Image sources: http://grassroutesjourneys.blogspot.com/2008/07/camping.html,
Source: James T Gill, Wilbur Wright College
15
C1
Biomass (1) – Direct Combustion
• Human use of fire is pre-historic
• FIRE! requires the right mix of 3 things; fuel
(biomass), heat (heat), and air (oxygen).
NOTE - The fire “triangle”
• Used when & where heat (or light) is needed
immediately.
–
–
–
–
Space heating
Food preparation/cooking
Other “process” heating
Lighting (Leading 3rd world light source!)
Image Sources: rabenseiten.de, spitjack.com,
goodtimestove.com, uncyclopedia.wikia.com/
16
C2
Biomass (2) – Seed Oils
•
Seed Oil is the oil that can be squeezed
out of seeds.
– Many of these oils may be used “as is” for
fuel or converted into what is known as
“bio-diesel.”
– Viscosity is an issue: Most oils can be
“thinned” or heated to be made less
viscous.
– Ideal viscosity is equal to that of #2 Diesel
oil for use in ICE (internal combustion
engines).
•
Ideas to learn:
-
SVO/WVO = un-used Straight Vegetable Oil / filtered Waste Vegetable Oil.
“Un-thinned” oil requires being “atomized” as in mist-injection and/or specially
designed fuel injection engines
To learn more about Bio–fuels and Bio-diesel Seed Oils, visit:
http://journeytoforever.org/biodiesel_yield.html
17
C4
Biomass (3) – Anaerobic Microbial Decomposition
• Methane = 98% of Natural Gas
•
•
Methane = CH4
Methane = a common anaerobic
• Methane from such sources is
known as Bio-gas!
digestion bio-material generated from
a 2-step process:
– Acid-forming bacteria break down
organic matter creating simple
acids:
•
•
•
•
acetic (vinegar),
butyric,
formic, and
propionic.
– Methane-forming bacteria make
“bio-gas” which is:
•
•
•
•
•
methane,
hydrogen sulfide,
ammonia,
CO2 , and
water vapor.
18
C4
Biomass (3) – Anaerobic Microbial Decomposition
There is long and deep tradition in many
places and times in
Ethanol Fermentation and Distillation!
•
C2H5OH = Ethanol = Ethyl Alcohol!
An old and tested recipe and a long
standing Chicago tradition –
making Moonshine! It involves:
• Milling – expose starch, increase
surface area
• Cooking – amylase conversion of
starch to sugar
• Fermentation – yeasts consume sugar
and excrete CO2 and C2H5OH as
metabolic wastes – BEER!
• Distillation – boiling the beer, and recondensing the C2H5OH at its precise
boiling point…makes an
azeotrope…95% C2H5OH = 190 >>
Proof Everclear!
• Azeotropic Distillation – A special,
involved process – not easy at
home!
• Waste Disposal – “every moonshiner” must deal with the left overs! 19
C4
Biomass (3) – Anaerobic Microbial Decomposition
An old and tested recipe and a long
standing Chicago tradition –
20
C3
Biomass (4) – Pyrolitic Decomposition
•
Pyrolysis is heating organic material in the absence
of oxygen.
– Heat drives off volatile gasses, and this leaves behind
“char” material.
– The volatile gases being driven off are combusted
immediately and used as fuel.
•
The solid char is stable so can
be stored and used later as a
solid fuel.
21
Biomass Evaluation – by Energy Content
Which of these appear to be the most promising?
Biofuel
Source
Percentage of
Water Fertilizer Pesticides land required
Energy
Content
Corn
Medium
HIGH
HIGH
200%
HIGH
Sugarcane
HIGH
HIGH
Medium
50%
Medium
Switch
grass
LOW
LOW
LOW
80%
LOW
LOW
LOW
200%
LOW
LOW
LOW
2%
HIGH
Wood
residue
Medium
Algae
Medium
Percentage of U.S. crop land required to meet half of U.S. fuel demand.
Table from Groom, Gray & Townsend in Conservation Biology
22
D2
Algae Bioreactor
Source: energy.ca.gov
E
Biomass: Using it for Combined Heat & Power
Conventional Fuel
Power Plant
Fuel
(Coal, oil, nuclear, gas, etc.)
Steam Turbine
Generator
Electricity
to Grid
Boiler
High
Pressure
Water
High Pressure
Steam
Low Pressure
Water
Low Pressure
Steam
Heat lost to
atmosphere
Cooling Tower
Pump
Content source: TurboSteam.com Sean Casten
25
E
Biomass: Using it for Combined Heat & Power
Conventional
Lumber Mill Plant
Pressure
Reduction Valve
Mill waste
Boiler
High
Pressure
Water
High Pressure
Steam
Low Pressure
Steam
Heat to
more
lumber
Low
Pressure
Water
Dry Kiln
Boiler Pump
Content source: TurboSteam.com Sean Casten
26
E
Biomass: Using it for Combined Heat & Power
Specialized Lumber
Mill Plant
Steam Turbine
Generator
Electricity
to Plant
Mill waste
The opportunity:
Boiler
Convert
conventional
wood kiln drying
plants into CHP
plants!
Isolation
Valve
Isolation
Valve
Heat used for
more lumber
Dry Kiln
Boiler Pump
Content source: TurboSteam.com Sean Casten
27
B
Biomass – Fuel versus Food
“Fuel versus Food” is one of at least three issues
developing at the intersection of Agriculture and
Global Warming. Perhaps the biggest of these
three issues is how climate change is changing so
many aspects of agriculture, with areas facing
unprecedented rainfall and drought.
“PRICE SPIKES: Have increased the
number of hungry people
worldwide in recent years, and led
to food riots in several countries.”
(Sunday New York Times, June 5,
2011)
International Food Policy
Research Institute:
Biofuel production will push
global corn prices up 41%,
oilseed costs up by 76%, and
wheat prices by 30% by 2020.
28
What about the Carbon?
• Biofuels are considered carbon neutral
– What goes into the atmosphere is recaptured by
the next generation of biofuels
• Fossil fuels not so…
– Billions of years of carbon pressurized and buried
in the earth are reintroduced into the atmosphere
– How long will it take to recapture it?
Biomass – The Carbon Cycle
•
“Fossil” carbon is carbon from
Earth’s ancient atmosphere,
currently “sequestered” in the crust
of the earth.
•
When we use fossilized carbon as
a fuel source, we are helping
restore the ancient atmosphere,
which was very, very hot.
•
Solution: Use “short-cycle carbon”
fuel resources.
•
These return to the atmosphere
carbon that was only recently taken
out of the atmosphere by biological
organisms.
•
“Short-cycle carbon” is referred to
in this case as “biomass.”
Image source; Wikipedia Commons
Image source; princeton.edu
30
Source: James T Gill, Wilbur Wright College
A
Regional examples of Biomass
•
•
•
•
Munster landfill
Fair Oaks Dairy Farm
Gary Sanitary District
Culver Duck Farm
WIND Energy
• form of energy conversion in which machines
convert the kinetic energy of wind into
mechanical (windmills) or electrical (wind
turbines) energy
What will wind power do for you?
• The “Big” Picture – Big Wind
• Average homeowner electric consumption
7,600 kWh/yr = 7.6 MWh/yr
• Big wind – 1 MW turbine in a 30%
capacity location – 1 MW * 8,760 hrs/yr
*0.30 = 2,628,000 kWh/yr or 2,628
MWh/yr
• 2,628/7.6 ~ 345 houses’ of electricity/year
2/27/2008
Wind 101 Workshop
©Illinois Solar Energy Assn.2008
www.illinoissolar.org
33
What will wind power do for you?
• The “Little” Picture – Small Wind
• Average homeowner electric consumption
7,600 kWh/yr = 7.6 MWh/yr
• Small wind – 5 kW turbine in a 20%
capacity location – 5 kW * 8,760 hrs/yr
*0.20 = 8,760 kWh/yr or 8.8 MWh/yr
• 8.8/7.6 ~ 15% excess generation of
electricity for the year
2/27/2008
Wind 101 Workshop
©Illinois Solar Energy Assn.2008
www.illinoissolar.org
34
Drag and Lift Devices
• Drag devices: typical VAWTs (not all VAWTS)
– 15% of wind power can be captured
– Windmill (Windmills and wind turbines are NOT
the same thing)
• Lift devices: typical HAWTs (not all HAWTs)
–
–
–
–
Use aerodynamic foil like airplane wings
Operate at several times wind speed that propels them
Very high lift-to-drag ratio
59% of wind power can be captured
(Betz’s Law)
Comparison of Different Axis Systems
2/27/2008
Wind 101 Workshop
©Illinois Solar Energy Assn.2008
www.illinoissolar.org
36
VAWT’s
Vertical Axis Wind Turbines
Source: Google.com
HAWT’s
Horizontal Axis Wind Turbines
Not windmills…
Source: Google.com
Don’t be fooled by ridiculous claims…
Source: http://worldenergyintel.com
Wind Energy
• Wind turbines typically rated by size of
generator
• A 100kW generator with 4’ rotor blades is still
considered a 100kW wind turbine
• Power is a square function of diameter of
windswept area
– Double the rotor blade length= 4X power
• Moral: Use longer rotor blades, but not
necessarily more rotor blades…
Wind swept area for horizontal axis
• The wind swept area of a
horizontal axis turbine is what
the blades cover, or more
simply, r2
• A 40 foot diameter blade
system covers four times the
area as a 20 foot diameter
one.
2/27/2008
Wind 101 Workshop
©Illinois Solar Energy Assn.2008
www.illinoissolar.org
41
Wind swept area for vertical axis
• The wind swept area of a
vertical axis turbine is what
the blades cover.
• In the case of this Darrieus
Rotor, it would be the radius *
½ the height.
http://www.energy.iastate.edu/renewable/wind/wem/images/wem-08_fig03.gif
2/27/2008
Wind 101 Workshop
©Illinois Solar Energy Assn.2008
www.illinoissolar.org
42
Wind energy
• Power is a cubic function of wind speed
– Double the wind speed= 8X power
– P2/P1 = (V2/V1 )3
P2 = (12/10) 3 P1
P2 = 1.73P1
• Moral: Get the turbine in the higher wind;
use a taller tower!
• Air density is directly proportional to power
Height does matter
2/27/2008
Wind 101 Workshop
©Illinois Solar Energy Assn.2008
www.illinoissolar.org
www.omafra.gov.on.ca
44
Wind Turbine Design factors
• Stay away from building mounted designs
– Stress factors, noise, turbulence
• Use taller towers
• Use turbines with longer rotor blades
• Lower RPM turbines tend to last longer/have less
maintenance
• Watt hours/$ is bottom line
• VAWTs typically more $/Wh; more materials used
in manufacturing…
Site Analysis
• 12-24 months on-site data monitoring best
• Consider using a small wind turbine instead of
anemometer…
• Wind ordinance maps online (Purdue)
• National Renewable Energy Laboratory-NREL
(http://www.nrel.gov)
• American Wind Energy Association-AWEA
(http://www.awea.org/)
• 3 Tier (http://www.3tier.com/en/)
• AWS Truepower (http://www.awstruepower.com/)
Siting Factors
Rules of Thumb
• Average wind speed and wind speed
distribution (wind rose)
Siting Factors
• Stay away from building mounted designs!!!
• Municipal ordinances on tower height
• Rotor assembly should be minimum 30’ above
tallest obstruction within 300’; I.e. 60’ trees, 90’
tower (minimum!), the higher the better
• Top of hill if possible
• Consider conduit/cable lengths
• FAA
• Small Wind Toolbox : Mick Sagrillo
http://www.renewwisconsin.org/wind/windtoolbo
x.htm
Siting Factors
STAY AWAY FROM BUILDING
MOUNTED DESIGNS!!!
Do Your Research!
• Don’t believe manufacturers’ claims
• Until recently, no certifying body; apples to oranges
comparisons for manufacturer’s ratings
• AWEA.ORG
• Anything written by Paul Gipe (wind-works.org)
• Home Power Magazine
• Midwest Renewable Energy Association
• Renewwisconsin.org/(small wind toolbox)
• Purdue University website
• http://extension.purdue.edu/renewable-energy/windenergy.shtml (7 hours of video)
Cost/payback
• The next several slides are included as
examples of cost vs. payback analysis
• They are not meant to be exact figures, but
rather approximate estimates to give you an
idea of the return on investment of a small
wind machine
• Costs do not include annual (or more…)
maintenance expenses
Example of output by wind speed
1 kilowatt nominal turbine
Wind power Speed
class
mph
Average
power
(watts) per
hour
KWh per year
(Whr * 8,760
hrs/yr)/1,000
Whr/kWh
1
9.8
100
876
2
11.5
150
1,314
3
12.5
200
1,752
4
13.4
250
2,628
2/27/2008
Wind 101 Workshop
©Illinois Solar Energy Assn.2008
www.illinoissolar.org
52
Example of output by wind speed
1 kilowatt nominal turbine
Wind power Speed
class
mph
Average
power
(watts) per
hour
KWh per year
(Whr * 8,760
hrs/yr)/1,000
Whr/kWh
1
9.8
100
876
2
11.5
150
1,314
3
12.5
200
1,752
4
13.4
250
2,628
2/27/2008
Wind 101 Workshop
©Illinois Solar Energy Assn.2008
www.illinoissolar.org
53
Return on Investment
1.8 kilowatt nominal turbine
Wind power Speed
class
mph
KWh per year
(Whr * 8,760
hrs/yr)/1,000
wh/kWh
Return on
investment at
$0.12/kWh
per year
1
9.8
1,576 $189.12
2
11.5
2,365 $283.80
3
12.5
3,152 $378.24
4
13.4
4,730 $517.60
2/27/2008
Wind 101 Workshop
©Illinois Solar Energy Assn.2008
www.illinoissolar.org
54
“Payback” of
1.8 kilowatt nominal turbine
Wind power Speed
class
mph
Return on
investment at
$0.12/kWh
per year
“Payback” on
post-incentive
installation
cost of $6,000
1
9.8
$189.12
32 years
2
11.5
$283.80
21 years
3
12.5
$378.24
16 years
4
13.4
$517.60
12 years
2/27/2008
Wind 101 Workshop
©Illinois Solar Energy Assn.2008
www.illinoissolar.org
55
Cost of electricity generated by
1.8 kilowatt nominal turbine
Wind
power
class
Speed KWh per Cost of electricity/kWh over
mph
year
the following years @ $6,000
post-incentive installation
-$6,000/(KWh-yr * yrs)-
10 years 20 years 30 years
1
9.8
1,576 $0.381
$0.190
$0.127
2
11.5
2,365 $0.254
$0.127
$0.085
3
12.5
3,152 $0.190
$0.095
$0.063
4
13.4
4,730 $0.127
$0.063
$0.043
2/27/2008
Wind 101 Workshop
©Illinois Solar Energy Assn.2008
www.illinoissolar.org
56
Other ways to think about costs
• Cost per kilowatt-hour
• System cost/number of kilowatt hrs generated-year * number
of years of expected life of system
• 10kW system costing $30,000 after incentives, generates
17,000 kWh-year
• 10 year cycle - $30,000/170,000 kWh = $0.176/kWh
• 20 year cycle - $30,000/340,000 kWh = $0.088/kWh
• 30 year cycle - $30,000/510,000 kWh = $0.059/kWh
2/27/2008
Wind 101 Workshop
©Illinois Solar Energy Assn.2008
www.illinoissolar.org
57
Wind turbines are noisy?
http://www.omafra.gov.on.ca/english/engineer/facts/03-047f12.gif
2/27/2008
Wind 101 Workshop
©Illinois Solar Energy Assn.2008
www.illinoissolar.org
58
Wind turbines kill birds?
Midwest Avian Impact Studies
•
•
•
•
Five studies
Impacting 254 MW
Average 2.2 fatalities/turbine-yr
Average 3.5 fatalities/MW-yr
http://www.eere.energy.gov/windandhydro/windpoweringamerica/
pdfs/workshops/2006_summit/kerns.pdf
2/27/2008
Wind 101 Workshop
©Illinois Solar Energy Assn.2008
www.illinoissolar.org
59
Keeping things in perspective
www.thegreenpowergroup.org
2/27/2008
Wind 101 Workshop
©Illinois Solar Energy Assn.2008
www.illinoissolar.org
60
Energy Storage
•
•
•
•
•
•
Batteries
Compressed Air
Water Pumping
Hydrogen/Electrolysis
Super Capacitors
Flywheels
• Energy derived from the sun in the form of
solar radiation
• Solar thermal
– Conversion of sunlight into heat
– Usually heating a fluid such as water or air
• Solar photovoltaics
– Direct conversion of solar energy to electricity
using the photovoltaic effect
Solar Thermal
Sun heats a fluid which is circulated through a
heat exchanger where it
preheats water, typically
for domestic hot water
or space heating.
Source: Google images
More solar thermal
Air heating
Solar Electric: Photovoltaics (PV)
• Direct conversion of sunlight into electrical
energy
• Creates Direct Current (DC) electricity; like a
battery
Source: Tim Wilhelm, PE
Solar Cell Model
• Notice the split between two
different types of silicon. N-type
silicon on the top, and P-type
silicon on the bottom.
• A solar cell is a type of diode –
this is the p-n junction.
Source: Tim Wilhelm, PE
Let’s Talk Sunlight
• Light is composed of tiny packets of energy called
photons. Photons may have different masses and
carry varying amounts of energy.
• When a photon strikes an atom, it can interact with
the electrons, and the photon’s energy can be
absorbed (heat).
• The additional energy can drive an atom’s outer
electrons off. An electron freed in this manner is
called a conduction electron because it is free to
move about.
• This is how sunlight stimulates an abundance of
electrons to be present on the N-type side of the
silicon.
Source: Tim Wilhelm, PE
What solar looks like in NW Indiana
Typical Grid-tied PV System
without battery storage
Source: Tim Wilhelm, PE
PV has many uses
•
•
•
•
Grid tied
Back-up power
Water pumping
Remote power for anything w/ enough
batteries
• Some experiments with solar power to
produce hydrogen through electrolysis to be
used in a fuel cell. Unlimited potential, but
extreme costs…
Maybe no uses are as
dramatic and
important as the
portable PV panels
and small
refrigerators carried
around Africa on the
backs of camels.
Source: Tim Wilhelm PE
72
Refrigerators like this,
carried on the backs of
camels and powered by
PV panels, allow vaccines
to be kept in good
condition and
transported to remote
villages where medicines
are needed.
Source: Tim Wilhelm PE
73
PV Works Well in Illinois
175
159
148
150
kilowatt-hrs/month
163 167
131
139
169
161
160
147
131
143
146 147
132
131
125
100
138
117
131
125
100
87
76
75
64
50
25
0
J
F
M
A
Illinois
M
J
J
A
S
O
N
D
Miami, FL
PVWATTS simulation – Natl Renewable Energy Lab, 1 kW AC, 30 degrees fixed angle due south
A solar electric system will work about as well in Illinois as one in Miami, Florida, around
90%. A PV system in Illinois can out-produce a Miami system in the summer.
Sources:1.Illinois Solar Energy Association http://www.illinoissolar.org/ 2.NREL
Sizing a PV system
• About 85-100 ft2 per kW of PV
• 12 months energy bills to estimate actual
energy usage
• Divide 12 months kWh by 365 to find average
daily use
• Divide by 4.4 average sun hours per day
• Divide by 0.8 for efficiency losses in DC-AC
conversion, and other factors
Sizing (cont.)
For example, you use 12,000 kWh/year:
12,000/365=33
33/4.4=7.5
7.5/0.8=9.375
You would need a 9.5 kw PV system to produce
all of your electrical needs for the year. You
would approximately 800-950 ft2 of south facing
roof top or other space for the array.
Costs
• Currently grid tied system about $5-$6 per
watt installed
9.375 kW * $5 = $46.875
Ooops!!!
That “k” means 1000!
$46,875.00 (pre incentive)
Advantages over wind
•
•
•
•
•
•
•
•
•
•
•
Little to NO maintenance
Greater longevity
Generally easier overall installation
No towers
Can be mounted on roof using otherwise more or less useless square
footage
No noise at all
No bird kills
No urban restrictions/set backs
Smaller residential size system cheaper per installed watt than wind
Easier to site (is there any shade?) and estimate annual output and
perhaps the most important….
Your children and grandchildren will think you are cool!*
*disclaimer-you have to be cool already for this to work properly.
Disadvantages…
•
•
•
•
•
The fuel source goes away every day
Shade is extremely detrimental to output
Expensive up front investment
Low density power per sq ft
Improperly installed systems can create
potential severe hazards (fire, roof leaks)
• Can alter building appearance negatively
BIPV
source: Google Images
Resources
• Photovoltaic Systems by Jim Dunlop
• Photovoltaic Design and installation Manual
by Solar Energy International
• MREA https://www.midwestrenew.org/
• SEI http://www.solarenergy.org/
• Indiana Renewable Energy Association
http://www.indianarenew.org/
• NABCEP.org
Questions?
Feel free to contact me