Click on the link in the story to be taken to the magazine.

One of our SolarYpsi supporters, Matt Grocoff from Greenovation.TV in Ann Arbor alerted me to a close out sale of Evergreen panels from Sun Electric for $0.78/watt! I could not pass up a price like that.

A quick phone call to Corinne the Ypsi Food Coop manager and a survey of the roof, we ordered eighteen 220-watt Evergreen panels for another 4 KW to add to the roof. Here is the datasheet if you want more details about the panels.

The panels were shipped by R+L Carriers and I was able to pick them up at there warehouse just off Ecorse. Here they are being unloaded behind the Ypsi Food Coop.

These panels are bigger then the Sanyo panels we have been using.

Robert helped moved the panels into the back of the Ypsi Food Coop where they will sit until we have some warmer weather.

I’ve started working on a rack design and got a quote for the inverter and racking material. My first rough estimate is that the ROI on this installation will be about 8 years. Maybe shorter depending on how quickly electrical rates rise.

Speaking of videos, The Google search ad video about SolarYpsi is creeping up on a 1/4 million hits. Pretty amazing for our little solar project.

One of the most exciting things with this addition to SolarYpsi is the relative ease with which new installations can be added to SolarYpsi. Anybody who is using Enphase products can be included on our website with only a few minutes worth of work and without the need for one of our old laptops. There are already a couple of other locations that may be coming online soon!

Finally I took it home and took it apart. I found that the heat sink fan was not spinning and filled with a lot of lint. I need to remember to clean the old laptops before I use them as data collectors. I have ordered a new/used heat sink fan.

In the mean time, I had another old laptop available and was able to swap the hard drives and get it running at the bakery data collector.

Hopefully this laptop will last longer.

So what is the current ROI for solar in Michigan, one of the cloudiest places in the nation. Solarbuzz ran an article a couple of weeks ago about global solar panel prices, and shows that today there are many panels for under $3.00/watt and you can buy some panels for as low as $2.50/watt.

Solarbuzz Retail Module Price Index

Michigan gets about 4 hours of peak sun per day. A theoretical 1-watt panel would generate 4 watt-hours per day, or 0.004 KWH per day. If I could sell or offset buying traditional power at $0.12 per KWH, that 1-watt panels would make (0.004*0.12) $0.0005 per day. A solar panel that cost $3.00/watt would take (3.00/0.0005/365) ~17 years to break even. For $2.50/watt the payback period is ~14 years.

These numbers get even better if you add inflation to the cost of traditional power for the 30 year life time of the typical solar installation. You can also add in the current 30% federal tax credit which is still in effect. This gets the payback period to about 10 years or better. While still longer then most people want, it is a positive ROI and if it pays for itself in 10 years, that’s 20 years of free power. Sounds like a good deal to me.

Solar Comparison Graph for Oct 23, 2011

In the graph you can see that the Bakery generates more than twice as much power as the other sites. This is because it’s a 6KW systems where as the others are all around 2.4KW. You can see that it was cloudy in the morning and sunny in the afternoon. The Bakery’s power drops off faster than normal because it starts to get shaded from some tress. You can see that with the Ypsi Food Coop panels too at around 4:30pm in the afternoon. You can also see that Adams School’s power get’s clipped a little in the very late afternoon. City Hall is very high and has no shading issue, so the parabolic curve is smooth all the way to sun set.

Note that this clipping is worse in the winter, since the sun is lower in the sky. It will be interesting to look at this comparison graph again next summer.

Click on the link and play around with the graphs for different days or weeks. If you click on the names in the legend you can turn individual curves on and off.

Yes, we need to get over to the Bakery and Ypsi Food Coop and trim some trees.

Thanks again for your continued support. Again, please let us know if you find something on the website that doesn’t seem right.