What would it take cut my utility bill and go green by adding some solar panels to my house? And can I afford to do it?
It turns out that understanding the move to solar power requires:
- An internet connection for research
- A bunch of previous utility bills for comparison
- At least a few phone calls
- A couple of building permits and inspections
- Some black magic, and
- Money and help from the outside.
After seeing a recent post from a local solar energy company in my area I decided to check it out. Motivation: cut the utility bills for my house and office, and have a little less reliance on The Man aka “Big Oil” and his fossil fuel buddies. Being an Architect I knew going in that a) this isn’t a DIY job, b) being in Dallas means there are probably some rebates out there to offset the cost, and c) I’d still have to fork over something to get those shiny blue silicon panels up on my roof. More on that later.
First, what does a solar panel system entail? I quizzed the “solar estimator/engineer” I spoke with about what gets added to the home’s wiring and electrical system. Note that there are really two kinds of “solar panels”. There are solar panels that heat water being pumped through them, and there are photo-voltaic panels that generate electricity. For this post I’m writing on the photo-voltaic kind of panel. The main parts are:
- The solar panel array on the roof. They should be oriented for maximum sun exposure.
- An inverter unit installed next to my utility meter (to convert DC power to AC to run household appliances, lights, etc.
- A free breaker in the existing electric panel, to power the inverter unit
I gave the solar engineer a bunch of data so they could design the size of the solar system. Given my electricity usage patterns, the orientation of my roof, and how much average sun Dallas receives daily, they came up with a 24-panel system that (annually) should pump out 8,615 kilowatt hours (kWh). Each of the 24 panels measures 3 by 5 feet, so this array fills up 360 square feet of my roof. Don’t forget that the installers have to anchor the panels into frames that are secured to the roof – that means bolts or screws that penetrate the roofing and down the way probably need maintenance to avoid leaks.
Simple enough. I came to understand that once I say “go” there will be a site visit to review the parameters at my house, 3-4 weeks for a building permit to allow construction to start, then just about 2 days to install the system. One caveat – once the installers and electricians do their thing the public utility company has to sign-off on it (you a green tag) before you can start harvesting solar energy for free. The green tag process probably takes another 2 weeks. So in total it is estimated to be about a 7-week process.
But can I afford the system, even with potential public utility rebates? The solar estimator took the data I gave him and provided me with a simple breakdown of the installed cost, the public utility incentives (which in the Dallas area can range into the thousands of dollars if you manage to snag them), an estimate of my federal tax credit for going green, and data pertaining to the break-even time and how much money the system saves me over its 25-year lifespan. Oh yeah, these things don’t last forever. They do have a warranty, however, and I learned it covers damage from high winds and small 1-inch hail impacts.
I took the system output (8,500 kWh per year) and divided it up by month. In the past we have averaged about 11,000 kWh used per year. I allotted slightly more solar output in the sunny summer months in case you’re wondering why each month isn’t perfectly even. Local weather conditions vary across the US, but the engineers can average 15 years of weather data to nail down a usage chart for your home.
I specifically had the solar company oversize the system a bit to see how much I could get off the grid. But doing so costs a bit more. The charts above break out my grid vs. solar power by month and year. You can see that almost 80% of my future electricity would be solar and thus free – and in April I’d stand to have an electricity surplus I can sell back to the PUC.
It would take a larger system to go 100% off-grid, and this size system is already expensive to me. The break-even point for my home comes after 9 years on the solar system – and I don’t think we’ll be living in this house for 9 more years thus making this deal not a deal….for now. Thinking forward to the next modern house for us means running this exercise all over to see if building on solar panels from the outset works. I imagine it would.
Hope this post my have answered a few of your questions or at least started you thinking about alternative energy. I have specifically not mentioned system cost or how much incentives and rebates are worth as these are variable in nature. If you have more questions I recommend you contact a solar installer in your area to learn more. My calls and estimate were free of charge, and very informative.
Now go turn off that light you left on in the kitchen and save a few watts!