Household Battery Backup

When we added the first eleven solar panels to our roof three years ago, we also added a Tesla Powerwall 2 (lithium- ion) backup battery (rated at 14 kWh) to the mix.

The greatest advantage to me, is the ability of our house to ‘keep the lights on’ during a grid outage, provided: a) the battery has a charge on it, and/or b) the solar panels are producing energy. In a recent blog, Solar Energy in the Rain, I wrote about our solar panels produced energy, even in the rain. So yes, solar works in Pittsburgh, even more so on a sunny day!

It has been said that Tesla is a computer software company first, while being an automobile and renewable energy company second. Sure enough, the Powerwall 2 has an awesome smart phone app to control various features, while also reporting on home energy production and usage (with present moment, day, month or year). One of the software features is a “Backup History” which records the date and duration of every power interruption where the Powerwall has kicked- in (with a minimum of 5 minutes each) during a power interruption.

Over a 3-day period at the end of May and into June, I noticed scores of interruptions which were evidenced by quick blinks in our lights (without us having to reset any clocks) and documented in the Tesla software app. The number of outages increased from May 31st to June 1st, so I called West Penn Power. My retired electrician neighbor told me it was likely a bad connection from the utility pole to our house, or the pole transformer itself. A supervisor arrived on the scene shortly after my phone call, and she determined the transformer on the utility pole across the street was overloaded, and needed replaced with a larger one that could handle twice the capacity. Everything is back to normal now with the transformer seen in this photo:

When I talk to someone about getting solar energy, the first question out of their mouths typically regards R.O.I. or Return on Investment. In other words, how long before the system pays for itself. Since we enjoy cheap electricity rates here, compared to most parts of the US, solar energy is considered less advantageous, since our “compare to rate” is currently 5.60 cents per kWh (plus tax and other fees).

Of course, electricity rates go up over time, and there are many other factors in play, but the addition of the Powerwall likely extended our R.O.I. from 10 years to over- 20 years. The hard numbers ignore the other benefits of course, and the core reason we added solar in the first place was more about addressing climate change and our grandkids’ future, than it was about saving money. That being said, our net 2021 electricity cost, for powering our home and 8,000 miles of Chevy Bolt charging, may only be $10, with everything factored in. We paid it ahead!

Exciting new developments!

Even more so than that weird-looking Tesla Cybertruck, it’s the new, more traditional, all-electric Ford F-150 that has caught my full attention, even though they both share similar specs. It’s the home battery backup feature that interests me the most. The F-150 is a harbinger, at least in the best-selling pickup truck category, of what’s to come, with bi-directional charging. I can see the ‘pronouns’ coming now!

Details are still somewhat sketchy, even for those who have put down a refundable $100 deposit to get in line for Fall 2021 ordering, and early-2022 delivery, but I saw reference in a story yesterday to the truck’s battery size being 155 kWh, which is the equivalent storage capacity of 11 Tesla Powerwalls!  Granted, that battery option is likely $10,000 more than the one that comes standard in the $39,900 base price F-150, but it would likely cost someone about $60,000 or $10,000 more, for an equivalent amount of home battery storage from 11 Powerwalls, without getting the truck. The Cybertruck may offer a similar scenario.

I’ve seen other reports indicating that most, if not all future Electric Vehicles (EVs) will have bi-directional capability. Volkswagen for one. I made a curiosity stop at our local VW dealer yesterday, and sure enough, they had 3 of the new ID.4 models in stock, with one window sticker indicating the EV had an 82 kWh battery with a 260-mile range for about a $50,000 list price, not considering incentives, rebates and income tax credits.

This is where the rub comes in.

Last I heard, if you buy a new EV from a manufacturer who has sold less than 200,000 EV’s, you are eligible for a $7,500 federal ITC (Investment Tax Credit) and potential $1,000 rebate from Pennsylvania. So what does that all mean? If you buy a new Tesla or General Motors EV, the federal tax credit has already expired. If you buy a new F-150 before Ford sells 200,000 EV’s, that $7,500 tax credit could bring that $39,900 sticker price closer to $32,400 (not including tax and fees). Big difference!

Whether you get that $7,500 I.T.C. from a new EV, or a 26% I.T.C. from installing solar panels (and/or home battery backup charged 100% by solar), keep in mind that it’s a tax credit that has to be offset by tax liability. In other words, you have to “owe to receive” the benefit, and last I read, the EV credit is only good for that particular year, while the solar tax credit carries forward. Retirees can create tax liability, to offset an I.T.C. by converting traditional IRA’s to Roth IRA’s, while the working man or woman will find the tax credit easier to use. You may also have additional financial benefits if you live in one of these ten states:

  • Arizona
  • Hawaii
  • Idaho
  • Iowa
  • Massachusetts
  • Montana
  • New Mexico
  • New York
  • South Carolina
  • Utah

Please keep in mind, that I’m not an attorney or a tax professional, so you need to double-check all these details for their accuracy.