Batteries included 2

Before I get to reader comments and questions, though, in last week’s column I mentioned that we likely wouldn’t be getting a home battery system due to the initially quoted $18,000 cost. As it turns out, further talks with the company brought the cost down substantially to $13,500, installed, for the two batteries we’d need. That lower price, along with the tax savings we should receive next April, brought the system into a price range we were comfortable with, so we signed the contract. It’ll be a couple of months before everything is installed but, once it has been working for a while, expect to hear more from me on the subject.

Responding to last week’s column, one reader asked for more specific cost data, and wondered what the expected payback for a system like ours would be. Over the years, we paid $36,000 for the 18 panels we have today. However, the price per panel has come down while the amount of power generated by each panel has risen. I calculate that an equivalent system to what we currently have would cost closer to $27,300 today. As for payback, using current per-kilowatt-hour pricing from our latest bill and the amount of electricity we would have had to purchase over the past 12 months if we didn’t have solar, I calculate that our system will have paid for itself after eight years (and, according to my math, an all-new system today would pay itself back in just six years). And that is based on the full cash price of the system, before taking into account the substantial tax deduction we received.

We paid the full cost of our system up front, but soon we received 30% of the cost of the system in the form of a tax deduction. Further help is often available from local governments and even from Pacific Gas and Electric. For instance, Bay Area SunShares is currently making discounts available (through Nov. 15) for those wanting to add both solar and battery storage to their homes. Bay Area Sunshares negotiates discounts with “prevetted installers” and passes the savings on to program participants. They get a cheaper system from an installer that has already been checked out — and still get the tax savings come April. Learn more and get a “zero commitment proposal” at bayareasunshares.org.

At one time, our home’s solar panels generated nearly as much electricity as we used in a year. However, buying an electric car and switching from a gas-fired heater to a heat pump has increased our electrical use to the point where, today, we only generate about 70% of our annual electricity usage. Batteries won’t help with that — they don’t generate power, of course, and in fact need to be charged to be useful — so we are also purchasing a couple of additional panels that should bring our total annual electricity generation to just over what we currently use. What the batteries will do is allow us to save some of the excess electricity we generate during the day — electricity that we sell back to the power company at a relatively low rate — and then draw upon that battery power at times when our system isn’t generating enough (or any) power. This will allow us to power our lights, the oven, our TV and even our heat pump at night using power we captured during the day. Ideally, we will no longer be purchasing any electricity during the peak hours of 4-9 p.m., when demand and rates are both high.

One reader noted something that I would have mentioned last week if only I’d had the room: Before spending money on any of these things, homeowners should first do what they can to reduce home energy usage. Ensure that your home is properly insulated, install blinds on windows that receive a lot of sunlight in the summer, switch all light bulbs to LEDs, and so forth (we even added a clothesline to our backyard, and we use it in place of our electric dryer as much as we can). Reducing your usage just may enable you to install a somewhat smaller solar system, and thereby save you real money.

Greg Wilson is the creator of Walking Redwood City, a blog inspired by his walks throughout Redwood City and adjacent communities. He can be reached at greg@walkingRedwoodCity.com. Follow Greg on Twitter @walkingRWC.