... #1 darling of the Prius chat (e.g., yours truly, excepted) ~

Thank you!

I'd heard about solar panel systems that required grid voltage to pace the AC power inverter. Lose the grid and you lost the solar power. I thought it was insane but wasn't ready to commit.

Bob Wilson

 

It appears the technology (no one wants to credit Elon) has gotten better. This is why we went the solar roof style. Three quarters of our roof is tiny little solar tiles that look like roof tiles. This helps us draw energy from the sun no matter what angle its at. Plus we are storing energy all day for use when the sun goes down. I would need 18 solar panels to draw near the same energy that my entire roof is drawing, and, my roof would look ugly. It truly is what Elon was pushing when he first envisioned solar roofing. Yes, the initial cost is more than someone getting panels put on their roof. But people need to do the math.

My roof looks awesome. I still get these solicitors coming to my door asking me if I was interested in solar panels! I then get to tell them that my roof is a solar roof.

When we were shopping for solar technology relief, I asked why doesn't one of these companies build a large detached patio with the roof being entirely made of solar panels? The people thought I was nuts. I told them its all about curb appeal and functionality. And, you could make it as large as needed to draw enough energy. I was scoffed at. Now, I see companies are starting to do this. Its the same principle that you see in government parking lots. The roofs are solar panels. Why not do the same for the consumer?

 

Excellent post.
I hope people pay attention to the important details that you included.

Like a lot of other things these days, scammers are quick to jump in.

 

Unless you are also putting in the hardware to enable back up operation, you didn't want the system producing in the event of an outage anyway. Solar back up sounds nice on paper, but the performance tends to be lacking. Adding a battery can easily double the price.

Maybe because solar shingles have been on the market for longer than SolarCity existed.
https://en.wikipedia.org/wiki/Solar_shingle

 

Grid-tie solar systems were long required to cease function when the grid went down, so not to work in island mode and back-feed energy into the grid. This is a safety function, to protect line workers and anyone else who might approach a downed line. The best way to implement this safety requirement was originally to build solar inverters on an architecture where they inherently could not function without the grid pacing them.

Newer system designs can now take a different approach: (1) act as an automatic transfer switch, to isolate the local production system from the external grid, then (2) use a local battery source to provide a synthetic grid signal for the solar inverters to latch on to, to allow them to function and provide local power, including recharging that battery.

Note that electrical codes have long required on-site emergency generators to use a transfer switch, which prevents the external grid and local generator from ever connecting to each other. The house can receive power from either source, but not from both at the same time. Old solar systems were exempted from the transfer switch requirement by ensuring they inherently couldn't produce when the grid went down. These new solar systems are now certifiable to handle this transfer switch / isolation automatically, thus allowing for local solar power production to legally resume for isolated local-only consumption.

These new systems, operating in automatic island mode with local battery storage, are considerably more expensive than the traditional style. The traditional style is still more cost effective for customers whose primary goal is to reduce or offset their electric utility carbon footprint, not for backup power.

I'd like to add this to my own home and solar system. My solar microinverters are even backwards compatible with such systems, with merely a firmware re-flash. But the costs of equipment (controller and battery) and utility service entrance reconfiguration are substantial. A sufficiently sized fossil fuel generator would be much cheaper, and work in our usually sunless winter conditions when utility power most commonly goes out, and be used infrequently enough to have very little impact on our overall carbon footprint. I can leave the self-standing solar to new construction (avoiding electrical service retrofit) in places with more unreliable power.