There seems to be one constant when it comes to solar panels: people have a lot of questions about them. About a year ago, Alex Moundalexis decided to install solar photovoltaic panels on his roof. When he started researching solar panels, he too had lots of questions, so he started taking notes; those notes have become a reference for ongoing reflection and conversation with friends and family. From making the initial decision to generating electricity for the first time took about three months, but since then, his small array has provided more than 90% of his home’s electrical need. Alex shares his experiences evaluating solar PV systems for his home, the resulting financial and energy impacts, and a few surprising things that popped up in the process. As presented at OSCON 2016 in Austin, Texas. https://youtu.be/FCeNer9F2wU

1. POWERED BY THE SUN
Alex Moundalexis
@technmsg
Slides: github.com/technmsg/sun-powered
CC BY 4.0

2. WHY ME?
18 months w/ solar panels
practical knowledge
computery guy by training and trade

3. WHY PEOPLE CHOOSE SOLAR?
reduce dependency on non-renewables
reduce utility bills
insulate against future energy costs
increase home resale value
cool factor

4. SOLAR PV 101

5. RESIDENTIAL PV SYSTEM

6. 0. SUNLIGHT

7. the sun delivers more energy to Earth in one hour than
humanity consumes over the course of a year
-- MIT Technology Review

8. 1. SOLAR PV MODULES

9. Photovoltaics is the direct conversion of light into
electricity at the atomic level.
-- NASA

10. remember solar calculators?
ever notice that old ones get flaky?

11. Photons strike and ionize semiconductor material on the
solar panel, causing outer electrons to break free of their
atomic bonds.
-- Solar Energy Industries Association

12. solar panel output degrade over time
most manufacturers warrant ~80% of rated power a er 25 years

13. 2. INVERTER

14. converts direct current (DC) into alternating current (AC)
(apologies to Nikola Tesla)

15. 2A. PRODUCTION METER

16. measures what the system produces

17. 3. FUSEBOX

18. backfeeding
bus bars don't care about the source of power

19. 4. BATTERY (OPTIONAL)

20. expensive
heavy
maintenance

21. 5. METER

22. by default, meters measure absolute usage
net metering

23. 6. GRID

24. ACQUISITION

25. PURCHASE
you own it
all the incentives
cash up front / special loans

26. LEASE / PPA
vendor-owned
buy power per-kWh
typically zero down
no incentives

27. COMMUNITY SOLAR
shared roo ops & spaces
shared costs
shared incentives
co-op style

28. PICKING A VENDOR
shop around
savings calculations (kWh)
3rd party contractors
reputation
local presence

29. PAPERWORK

30. INSPECTION
roof: dimensions, orientation, gotchas
attic: truss spacing
electrical: panel

31. SYSTEM DESIGN
CAD drawing
power output report: accounts for dimensions, orientation, roof pitch, shade,
time of year

32. INTERCONNECT
notifies utility of intent to generate power
proper billing
safety for utility workers

33. INCENTIVES
federal / state / local
grants
tax credits
www.dsireusa.org

34. HOA APPROVALS
solar easements and rights laws
(tedious)

35. SREC REGISTRATION
Solar Renewable Energy Credit
1 MW = 1 credit
commodity market
typically sold via aggregator to utilities

36. EXAMPLE SYSTEM #1
16 SunPower panels
SunPower inverter
3.92 kW
purchase
17,000 USD

37. EXAMPLE SYSTEM #2
24 Yingli panels
SolarEdge inverter
6.63 kW
20 year PPA @ 11.3¢/kWh
zero down

38. EXAMPLE SYSTEM #3
20 unknown panels
unknown inverter
6.25 kW
20 year PPA @ 6.1¢/kWh
7300 USD pre-paid in full

39. INSTALLATION DAY

40. BEFORE

43. DURING

50. AFTER

54. ACTIVATION

55. waiting...
for a County inspector to check structure & electrical
for the power company to install the net meter

57. (anticlimactic)

58. BREAK?

60. IMPACT

61. DAILY
with net metering, usage unchanged
most days production > usage
w/o net metering, migrate demanding tasks to daytime

62. Energy Produced on 2 May 2016

63. MONTHLY
production varies by season
no maintenance required

64. Energy Products in 2015

65. LONG TERM
12 months in...
85% of my electrical needs
50% expenses recouped
payoff expected in 5-6 years

66. MONITORING

67. Dashboard

68. GAMIFICATION
inevitable, given data
measure everything
minimize usage

69. DAILY USAGE

70. BIG USES
2 kWh - fridge
2 kWh - always-only Internet**
** fiber ONT, router, UPS, two wireless routers, Chromecast, VOiP bridge, VOiP handsets, core switch

71. LIGHTING
largely overlooked
inefficient incandescent
3-way bulb > entertainment center

72. ELECTRONICS
most modern electronics are wildly efficient
1 kWh - 8 hrs WFH: laptop, monitor, speakers
¼ kWh - stream a movie on home theater

73. STANDBY CONSUMPTION

74. INKJET PRINTER
1.4W standby
0.1W powered off

75. DELL FLAT-PANEL
35-45W in operation
3.7W standby
3.6W powered off

76. DOWNSIZING

77. HOME SERVER
Dell PowerEdge SC 440
100W = 72 kWh/month = $9.36
vs
Raspberry Pi B+
1.6W = 1.5 kWh/month = 20¢

78. (ENERGY) PRODUCTION DATA
REST API
web scraping
to automate browser activitySelenium

79. ENPHASE
The allows mobile apps, building
management tools and other so ware applications to
access and use system performance data.
--
Enlighten API
Enphase Support

80. SOLARCITY
The PowerGuide API is a RESTful service that can be
invoked from any HTTP client, and allows you to query
PowerGuide Data.
-- PowerGuide API documentation

81. SUNPOWER
The API was developed for our flex applications and there
are no plans to make it available to 3rd party developers.
-- @sunpower

82. CSV
Interval Start Date,Energy (kWh)
2016-05-14T05:00:00,0
2016-05-14T06:00:00,0.040
2016-05-14T07:00:00,0.160
2016-05-14T08:00:00,0.270
2016-05-14T09:00:00,0.390
2016-05-14T10:00:00,0.930
2016-05-14T11:00:00,1.440
2016-05-14T12:00:00,1.530
2016-05-14T13:00:00,2.780
2016-05-14T14:00:00,0.810

83. SPECIAL THANKS
Freedom Solar Power
SunPower
(show and tell goodies)

84. MORE WORDS
Blog: Going Solar
bit.ly/v2-solar
Get solar (via SunPower)
bit.ly/get-solar
Slides
github.com/technmsg/sun-powered

85. THANKS
Alex Moundalexis
@technmsg