Solar

So I went solar. And as the process of learning everything I needed to know was somewhat involved, I thought I'd share some of my experience. By the way, my friend Rebecca says it is bad form to start a sentence with "So" and it is also bad form (in fact, aggressively looking for affirmation) to end a statement or diatribe with "Right?". But I do it anyway.

So solar. Basically there are a few choices - buy vs lease (I don't see a rational argument for leasing other than being green and not being able to afford solar). Then there is the panel choice. Then there is the installer choice. Then there is the consideration whether you will need a new roof any time soon (if so, do that at the same time). Finally, there is how much capacity to get.

There is a fantastic site that helps with all this, if you really want to geek out and know everything a lay person needs to know - SRoeCo Solar

The selection process:

  • The most important choice (and the one that will guide all the following steps) is your installer. This is like picking a contractor for a remodel. Get a bad one, you end up being unhappy with your project and you get crappy recommendations for capacity, panels, inverters, getting city permits, etc. The trick is that some installers prefer some panels (or are not authorized for them) so if you have a preference (e.g. wanting Sunpower) then that guides you towards an installer. Angie's List is worth looking at for recommendations, or yelp, but definitely talk to a few before you pick one (and get multiple bids).

    • If you live in the South Bay, I highly recommend Cobalt Power as the installer.

  • As homework/prep, start by figuring out your electric usage -- take a few years of bills, think whether you will be growing (AC, hot tub, electric car, etc), and based on that come up with an estimate. You have to take into account that your usage will probably go up when you get solar because you will be less incented to save on AC, you may leave the lights on more, because it is "free". A typical household is in the 10s of kwh per day (my usage is around 30-40 kwh/day but that's a pretty small house in a temperate climate).

  • Then figure out what you want your solar to cover. For me, it was simple: I NEVER want to pay for electricity again (even if I end up getting an electric car) and I like the idea of generating more than I use. Some people just want to shave off their top-tier usage (the portion of your bill where they charge you like 35c/kwh) but again I don't see the point of going through all the trouble for that.

  • Also look at how much surface area you have -- south/west facing, unobstructed by trees, etc. -- that's a real constraint for some people, not for me. If you are constrained, you may not be able to cover all your usage, even with the most efficient panels. Where you live makes a difference (number of sunny days and sunlight hours).

Given all that, you end up with how big a system you want to build - e.g. "I want a 9 kW system" -- any solar installer can help you with that calculation. My recommendation is treat it like buying a hard drive - go higher than the number you compute. I have an 8.1 kW system (not sure how they compute that but the installer will tell you) and it generates more than 60 kWh/day on sunny days in June, about 40 on sunny days in October, but only about 10-20 on rainy winter days. But PGE computes your net usage over the whole year.

  • Now the panels. There is a lot of choice there, but in the end, for all the marketing hype, the difference between "cheap" and "expensive" is not a huge part of the cost - what you are partially buying is reputation and long-term warranty (if you go with the cheap-o panels, and one of them fails five years from now and the company no longer exists, where do you go?). The efficiency may seem like it does not really matter anymore (and people will try to tell you that), but where it comes into play is how much of your roof will be covered by panels. Especially if the panels are on the front of your house, looks matter.

    • Based on that, plus quality/ratings/efficiency/etc, I decided on Sunpower - still by far the most popular panel here in the Bay Area even though they are not the cheapest. Still the most efficient panel, and they have a great warranty.

  • Your installer will also recommend an inverter. This is what turns the current that gets generated on your roof into the stuff that your house (and the grid) uses.

    • I ended up with SolarEdge inverters - very happy so far. Some are more efficient than others, etc.

  • There are some smaller choices as well - e.g., do you want the power line to go under the roof (prettier) or over the roof (cheaper).

  • And don't forget about the federal tax incentive (the California rebate has run out -- part of the fun of being a late adopter). Your installer will tell you all about it. It's real money - it ends up saving you about a third of the cost of the project.

Anyway, you can tell it's a pretty big project if you do it right, but when all is said and done, my PG&E bill went from $350/month to zero -- so even with top-of-the-line capacity, panels, installer, inverters, etc, that is a payback period of about 6 years and sooner if you get an exact match between your usage and your capacity (e.g. if you get an electric car). Seems like a good deal. Right?