Finally Walking My Solar Talk

Intermediate

Inside this Article

Author drilling a hole to attach the PV array
Dave Strenski prepares to attach the rooftop PV array.
The home and PV array
Even with some reduction in efficiency, “non-optimal” array orientations, like on this west-facing roof, can pencil out financially.
Array visible from the street
Even though the PV system on the west-facing roof is visible from the street, the system was approved by the Historic District Commission.
Installing the PV modules
Homeowner and volunteer labor helped reduce installation costs. After rebates and projected production incentives, the calculated cost was about $1.16 per installed watt.
Photo of PV array
This west-facing array provides about 75% of the production of a similarly sized array that would be oriented to true south.
Microinverters
Enphase M250 inverters were installed on SolarWorld rails attached to Quick Mount PV flashed feet.
The load center
The Enphase Envoy production meter, which lives near the service panel, communicates to the Enlighten Web interface.
Screen shot of PV system web interface
The Enphase Enlighten Web interface allows real-time and cumulative tracking of individual module and whole-array performance.
Strenski family photo
The author and his family in front of the PV production meter.
Author drilling a hole to attach the PV array
The home and PV array
Array visible from the street
Installing the PV modules
Photo of PV array
Microinverters
The load center
Screen shot of PV system web interface
Strenski family photo

As a nine-year volunteer for SolarYpsi, a grassroots solar advocacy organization, I’ve helped design and install about a dozen grid-tied solar-electric systems in Ypsilanti, Michigan. Ironically, until recently, my own home’s rooftop had remained without photovoltaic (PV) modules.

I often dreamed of solar power for our family’s home, but the high initial system cost, the  home’s orientation, and its location in the historic district seemed like high hurdles. The front of our 122-year-old Victorian home’s gable end faces south with three large maple trees shading it, and its roofs face east and west. The backyard is filled with trees and a garden, so a ground- or pole-mounted system was not an option.

Then there was the cost of the system itself. In SolarYpsi’s early years, PV systems cost $7 to $11 per installed watt—and that was with using an all-volunteer labor force. My interest was renewed after I calculated the installation cost for our latest PV project at the Ypsilanti Food Cooperative. Using volunteer labor and $0.78-per-watt Evergreen PV modules from a bankruptcy sale, SolarYpsi was able to install the system for $3 per watt. This was the first time PV power seemed it might be affordable for non-ideal orientations or locations. More surprising was that the $0.78 per watt was not an anomaly. Later that summer, closeout UniSolar modules were available for $0.50 per watt after the company’s bankruptcy. That motivated me to start searching the Internet regularly, and I soon discovered that $1-per-watt PV modules were becoming common.

Three occurrences inspired me to revisit the idea of putting a PV system on our house. Our retired neighbor, Larry, was installing a PV system at his house, and he was able to self-install his system for less than $2 per watt (before incentives). He took a creative approach to the mount, purchasing aluminum channel for the rails at a scrapyard for a fraction of the cost of new rails. He also saved some money by fabricating his own top clamps and roof mounts. Note that creating custom racks can save some money upfront, but the responsibility of making sure all of the appropriate engineering calculations have been considered and  implemented  falls on the system owner (see Web Extras for an article on racking options for roof-mounted PV systems).

Then, a new PV installation company, Sade Power, established itself in southeast Michigan and was advertising batteryless grid-tied PV installations for $2.50 per watt. Another local solar contractor—AJ Leo—was also installing systems for about $3 per watt using Michigan-made PV modules and inverters.

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Comments (3)

Dave Strenski's picture

If anyone is interested in the "talk" part of the article, here is a video that Google made about SolarYpsi.

Dave Strenski New Energy for Detroit
http://www.youtube.com/watch?v=b6Vt...

And here is a TEDx talk about solar power I gave about a year ago.

Understanding Solar Power in Ypsilanti: Dave Strenski at TEDxEMU
http://www.youtube.com/watch?v=Mx0p...

Marc Fontana's picture

Thanks for sharing details about your DYI PV installation project. I love the hand powered drill !

I am curious about your selection of the Enphase M250 micro-inverter - The micro-inverters make sense for your shaded location, but I wonder why you did not select the less costly Enphase M215 model ? The M215 can produce up to 225 Watts and would still maximize your energy production with the Sonali SS-250 modules which have a PTC rating of 213.4 Watts. There's not a huge difference in price (the M215 is ~ $20-30 less) but it adds up. The newer M215's have same integrated ground and monitoring capability as the M250.

Dave Strenski's picture

I went with the M250 because of the integrated ground. I didn't know the newer M215 have the same integrated ground. Another pit fall of a DIY project.

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