Solar: My, what big batteries you have

That 50-hour power outage in January that sent me off to buy a generator also motivated me to finish the solar installation I started two years ago.  I did the panels first as it was a big job ("might as well do the roof first") and decided with local Mr. Solar Steve Pariani's input to wait on the batteries.  Two sleepless nights in January drove me to finish the project and Steve has just completed it--again on time and on budget.

Readers asked how much it cost and what is the warranty on the batteries.  The two Enphase batteries and some more associated interconnection devices came to a shade under $30K including the plans, the permit, installation and sign-off.  They also qualify for the federal tax credit ("ITC") of 30%.  The good news is that two years ago Enphase was only offering ten-year warranties, but now I have a 15-year warranty.  Here are the batteries as installed and the new Enphase app screen that comes with the batteries (as opposed to the simpler one for just having panels.)

Comments

[Joe]

By the way, each battery is about 4 feet wide, 30 inched high and 7.5 inches deep.

[Paloma Ave]

Joe - What were you paid or credit for the 22.9 kwh that were exported?

[Joanne]

What are the batteries for to run the solar or in case the power goes out? Sorry know nothing about this stuff.

[Joe]

The solar panels feed the batteries during the day. At night when electricity is more expensive the house draws from the batteries. When they are full and it is light out the excess solar power flows back to the grid. The real motivation was the two-day outage which the batteries will now back-up.

Paloma, I wish it was a simple as saying they credit X per kwh, but I think it's more complicated. They only "true up" once per year and the rates also vary by time of day, etc. It seems like I sort of broke even last year without the batteries-- there was lots of grid usage with all the rain and the need to run pumps for months. I think the cost/credit will be clearer next year, but I can also ask Steve Pariani.

[Joe]

Here's a snippet from the WSJ:

Battery storage has emerged as a tiny but important slice of the electrical-power mix during summer heat waves, helping bridge the gap at sundown when solar generation fades but everyone continues to crank air conditioners.

Before 2020, large-scale batteries barely existed. Now U.S. developers are planning record amounts of large installations across 29 states, according to the American Clean Power Association and energy consultant Wood Mackenzie. The sector has seen a sharp increase in additions even as the pace of delivering other clean-energy projects has slowed.

Companies connected nearly 1,500 megawatts of battery storage to the grid in the second quarter, enough to power about 300,000 homes during peak demand, up 60% from the same period last year, according to S&P Global.

The U.S. battery market is dominated by states such as California, Nevada, Arizona and Texas. Batteries earn money through providing services that stabilize the grid or by arbitrage, often charging up on cheap or excess renewable generation, then discharging later when energy prices and demand soar. Battery installations in the West might provide power for 3 to 8 hours, while those in the Midwest and Texas often discharge for an hour or two.

[Joe]

I just learned about a feature of my solar system that automatically checks for National Weather Service alerts like the heat advisory we just had for two days. When it sees one it reacts with this:

With Storm Guard, your Enphase Energy System can monitor severe weather notifications issued by the National Weather Service in the USA or the Bureau of Meteorology in Australia.

When Storm Guard is enabled, your battery profile is automatically set to Full Backup if a severe weather notification is issued for your area. This allows your full battery capacity to be reserved before a potential grid outage event.

While the severe weather notification is active, your battery gets charged from solar power or the grid, in that order of priority, depending on which is available. The battery discharges only when there is no grid power. Your battery profile returns to its prior setting once the severe weather notification ends.
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Cool!!