Bob Bruninga has written and researched this a great deal. He's pretty well known and respected. He feels grid tie is the way to go for homes (no batteries). Lots of great info here:

http://www.aprs.org/off-grid-maybe.html

http://www.aprs.org/solar-now.html

The main reason I would consider a battery is for disaster recovery purposes. Being from the suburban NYC metro area, we've had multiple, multi-week power outages in the past decade.

We have a moderate sized portable generator, but running off that for weeks becomes a very unpleasant experience. Certainly far better than not having power, but unpleasant.

Driving 2 hours away to the nearest place we knew had unlimited fuel, turning my car into a rolling bomb on the trip back with dozens of gallons of fuel in gas cans, etc. And the endless droning of the thing running.

If those sorts of disasters are not a major concern for you, I don't think a battery makes much sense.

Do you have natural gas available?

You can also store quite a lot of propane in a small footprint without some of the issues that come with gas or diesel.

> we've had multiple, multi-week power outages in the past decade

That's a crass state, what causes these outages? Is it a investment backlog of the power grid?

Hurricanes and early in the year snow storms (trees fall down on power lines), cause these things to happen.

Might have something to do with being in a very dense area with some very old infrastructure.

It depends on how much your electric company will pay you for excess energy production. Currently you may get a good rate, but as more people install solar panels that rate is going to get worse, as it gets more expensive to deal with all the homes with solar. So figure out what the deal is in your location, don't get a battery until you need it. I Don't know, but I realize in the future if Austin Energy doesn't pay well for excess production I will.

You can also size your panels such that you never produce excess energy but you will be leaving a lot of roof space that could be making energy to waste. A sunny winter day still makes a ton of energy.

The sun goes down at night

And? I'm still connected to the grid.

I think you are talking about off-grid vs. grid, but the others are not. The cost of solar applies also to utility companies, and I think that’s what GP was alluding to.

The grid will switch to solar + battery if it becomes cheaper than alternatives (gas, coal, nuclear, etc.)

Unless battery/storage tech gets wildly better, you're still going to have to have the natural gas turbine plants that we're currently using for peak demand power to smooth out the inevitable spikes and troughs in supply from solar/wind renewables.

It's such a damned shame that so many decades of potential progress in nuclear power were stymied by misguided FUD.

You're replying to a comment about the true cost of solar being the battery + the panels, asking why anyone would think of buying a battery.

That's why.

That still doesn't answer their question. Why does the sun going down at night matter for people who are still tied to the grid?

If I move into a house with a grid connection only, I budget on power costs = cost of grid connection + grid power price.

If I move to a house with solar panels, I budget on power costs = cost of grid connection + X * grid power price + (1-X) * solar price (which is the capital cost of the panels smoothed out over their useful life).

The issue here is that I can't maneuver into a situation where my power price = solar price without sacrificing my ability to do anything after sundown without candles. Clearly, the true cost of power in a solar-enabled house is going to be higher than the cost of the solar panels.

Because you are also a taxpayer.

Huh? Are you talking about subsidies?

Not just that, also infrastructure investments.