Birding Despite Disability

Obsessions Don't Care About Limitations

Harvesting Sunlight

I only wish I would have done this years ago.

Top of house, showing almost entire roof slope covered with large black rectangular solar panels.
Main south-facing section

We pulled the trigger last fall to install solar panels on our house. We have a roof that stands well above most of our trees, with a big south-facing expanse as well as good east and west exposures. We put a total of 49 panels up, each capable of 320 kW, making it a 15.7 kW system.

Roof of a house with gray shingles, six large black rectangluar solar panels mounted on it.
East-facing panels

During much of the day, the system delivers more power than we need. And thanks to the policies of Xcel Energy here in Minnesota, any excess we produce goes back into the grid, and we get paid for it.

Our electric bills, which could be several hundred dollars in past summer months, have turned negative – they are now deposits. Plus, Xcel will pay a yearly incentive for the next ten years, of about $1,200 per year. And the federal goverment is still giving a 26% tax credit for the cost of the system and installation.

What this all means is that we expect to break even in no more than seven years. After that, it is a pure money maker. In twenty years, which is when we might want to replace the panels with more efficient ones (almost certainly far more efficient and cheaper ones, by then), we expect to have pocketed over $50k in savings / earnings from solar. It is an incredible return on investment, with the bonus of seeing all that incident radiative power from the sun doing more than warming our shingles. Taking a concrete step towards a more renewable energy future feels good too.

Each panel has its own micro-inverter on the back, which converts the raw DC current into 60Hz AC. I can monitor, on my phone, each inverter via wifi, so I always know how the system is performing, and if a panel were to malfunction, it will be easily identified. Unlike a string of Christmas tree lights in series, if some panels were covered, say by snow, it won’t take the whole system down. They run in parallel.

Bar graph showing energy collected by panels versus time for a day. Energy increases from zero before sunrise and peaks int he afternoon. Energy usage also shown, which is less than that generated.
Enphase app screenshot for 24 hours of solar. The blue shows energy versus time as produced, the orange shows usage. The two excursions were from running the air conditioning. Overall, we net exported 29.1 kWh of energy that day.

If you have the means and have ever thought about going solar, this is the time to do it. Panel technology, efficiency, and robustness have only improved, and the 26% tax credit still holds through 2022. Depending on your state, you may see other benefits – Minnesota charges no state tax on a home solar project.

2 responses to “Harvesting Sunlight”

  1. Sounds good. I don’t know if we have the same programs in Canada but it would be worth checking up on.

  2. This is brilliant ! Cost cutting and eco friendly ! I recently bought a farm land to build house, planning to do it fully solar 😬 and rain water harvest + humidity harvest.

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