I have solar. So far, it feels like more of a "feel good" thing than a major economic benefit. Getting a 10kw solar array installed cost ~25k in our territory. Dealing with the local electric company was a huge pain, and the array doesn't actually feed the house (we sell power back to the grid). To really maximize the benefit, you need a powerwall, so you can store surplus energy, continue service during outages, and avoid taking a hit if the net metering agreement changes in the future. We're actually exploring this by way of the Ford F-150 lightning acting as a battery backup, but that also requires upgrading the house to a 400 amp service, so you really start feeling like you're getting in to sunk cost territory.

This was one of my major disappointments when I looked into solar the first time. I don't want to stick panels on top of my house that are basically just feeding back into the grid. I want to have panels that first feed my house, and maybe if there's extra feed it into the grid, but if the grid goes down I still have a more-or-less functional house. A big part of solar's value to me is the renewable, off-grid backup power. Solar has the interesting and useful characteristic that it keeps working even if things have really gone to pot and you've even lost gas and water for some reason. Having lots of houses like this scattered all over the place greatly increases civilizational resilience. (That is, I'm not so much trying to plan for "The End Of The World" just for me personally with my own solar install, but want the resilience at the societal level, and might be willing to pay to help it along.)

If solar's just going to feed back into the grid, I might as well just let the utility companies manage it themselves. It's more efficient than anything I can do myself.

Unfortunately, it seems like the way solar works helps that goal much less than I'd like. I hardly need multiple kilowatts of power backing a single functional outlet that almost seems begrudgingly provided.

I'd be interested in anyone who has experience in perhaps managing to set their house up the way I describe, what magic words to Google or say to installers to talk about this, and how much more money it may have been.

I used to manage solar installations, couple of things:

1. Electrically, solar does feed your house first. It interconnects before the meter and into your main electric panel. The reason it doesn't work during an outage is because of regulations requiring solar to turn off during power outages so that electricians fixing downed lines don't have surprise power from random houses after they turn off the grid power.

2. If you want solar to work during an electric outage you need to install a battery backup that can feed it AC power and disconnect it from the grid during a grid failure. However, you need a pretty big battery to power a full house for a long time so it's generally cheaper and easier to have a gas generator backup if you are worried about this. Batteries are really just good for energy arbitrage purposes these days.

3. There are inverters that have an outlet that works during grid outages, even without batteries (https://www.sma-sunny.com/us/how-to-explain-secure-power-sup...). They generally cost the same

The real money ends up being in the power storage. Obviously there's such a thing as 'night' and multiple days without full sun (or snow on your roof depending on the area).

I wonder how many electric F-150s will get sold to people on the basis of using them as a whole-house battery.

I fully agree on your point of the lack of logic to grid-based solar. No doubt large scale facilities can be placed in better areas, be cheaper per watt, have higher uptime, are able to afford the more exotic power storage (dams for one).

Now, if it were me, I'd start with new construction designed around low power usage. LED lighting, efficient computers, chest freezer turned into a refrigerator, no electric heat or dryers or transfer fans for gas heaters. The sticking point would tend to be A/C but I think that can be mitigated via small house size, insulation, and use of efficient split systems. The smaller the electricity use the more tractable the problem.

The term you are looking for is called islanding. When the grid goes down you want it to throw an automatic transfer switch and power your house from solar and/or batteries. When the grid returns, you want it to resync the AC wave and draw from the grid as needed. Check out the Victron Multiplus as an example.

Thank you. Sometimes working out that correct search term is the hardest part of the process!

My house is set up like you describe. The whole solar/battery system never interconnects with the grid, and is instead set up like a generator. There is a transfer switch to choose between "generator" power and grid power. If there is some exceptional weather and the battery gets too low, we switch to grid. If the battery is full and the day is sunny we often dump power into the car, air conditioning, or whatever.

What required the 400 amp service?

I do like the F150 as a backup power source, but there's probably a catch. I see that a Tesla Powerwall holds 13.5 kWh, and the truck is 115-155 kWh.

Average US house is 30 kWh / day? It sounds doable but not cheap.

I'm not sure about the 400 A comment either, but there's at least two "catches" to the F-150: it's ~$90k for that configuration and it's unclear how the charge/discharge duty cycle will affect it.

To be clear, even at $90k that's cheaper than buying a pile of power walls or similar. So it seems like it's a power wall array plus a free truck :).

The 90k price tag is for the highest trim model. The entry level is ~40k. We know the entry level won't be able to serve as a battery backup; however, there ostensibly a bunch of trim levels between entry and "ultra" with their own respective price points, and my understanding is that the details are still unclear regarding the lowest tier that supports this feature. If you have details, I'd love to see them.

>We know the entry level won't be able to serve as a battery backup

Why is that? A missing feature?

Originally I read that the inverter is part of the truck and would not be included in the lowest "pro" trim model. After further research, it sounds like the bidirectional charging comes as part of the extended range battery upgrade, which you can apply to any trim model (starts at $10,000 and goes down in price at higher trim levels).

https://www.f150gen14.com/forum/threads/trim-pricing-for-202...

Whoa, thanks! My data was based on the initial announcement.

Judging by this article [1], the bidirectional charging is maybe part of the $1000 "Pro Power" add on.

Either way, sounds like we can get a 100-ish kWh battery backup for $50k.

[1] https://autotrends.org/2021/03/01/what-is-bidirectional-char...

Generally electric vehicles handle wall -> charging.

Taking DC from batteries to connect to a 120V AC house is going to require an inverter which adds cost, weight, and space. Presumably the base model won't have it.

Except if the truck is out of town on a fishing trip but the rest of the family is at home, the powerwall is unavailable to the family where the power is out.

The charge station pro draws 80 amps. To use it safely, you need an outlet rated at 100 amps. My home is currently on a 200 amp service, and an electrician (also a close friend) told me I'd need a 400 amp service upgrade to provide adequate power to the whole house.

That's one thing I've always wondered about solar. If it truly just flows back into the grid, and you don't get access to it during a power outage, surely a centralized solar energy installation would be a lot more efficient than installing them on everyone's roofs. You end up paying much higher installation and maintenance costs - the only real advantage is that it's a plot of land that's readily available.

It wouldn't surprise me (although I'm not any kind of power engineer) if a world of house-based grid-tied solar wouldn't be a bit of a management nightmare for the power company as opposed to large plants.

I expect we get away with it right now due to rarity.

South Australia has so much solar, at times there is zero grid demand. It is a management nightmare for grid operators, but that's what they're getting paid for (instead of generation, which is shifting to direct payment from consumers with solar on their roofs).

The future of grids is orchestration between variable demand and variable generation, along with pumped storage, battery storage, and long distance transmission.

If everyone is producing electricity, who pays the bills?

Same people who pay for the roads and traffic signals?

Large solar farms take up a lot of land. Much more than wind does. It also makes that land useless for anything else other than solar.

Large wind farms generate more power than solar on a per acre basis and have a lot of land that can be used for cow/sheep grazing, buildings for other purposes, and so on.

Solar is getting so cheap that people can use them for "local solar" (in the industry, that's called distributed generation).

Rooftop solar on residential homes usually power the house first, then the battery of the house, then the grid. This could change if net metering is allowed though but usually only after your batteries are topped up.

Also you could just not have batteries (since it's so expensive). In that case any excess power will just go directly to the grid.

It's actually common for sheep to be grazed under solar and it helps keep the grass trimmer. Or the grassland can be managed for wildlife and polinators.

My guess is that solar sites will be managed to improve soil quality. And eventually we will rotate the fields under solar to give the soil a rest. It is the perfect opportunity for a win-win.

Yea, they graze under/around solar panels but that's pretty much all you can do for a solar farm. Wind gives you more opportunity to use the land.

I don't see the solar site management thing happening by the way. A lot of time and effort goes into land siting and selection. It won't be that easy to just pack it up and move.

What's wrong with putting solar panels under wind farms?

Nothing and some companies are looking at that. It changes the dispatch characteristics but that's not a big deal.

I can see this happening more in the future when you kind of run out of space and have increased demand for power. First thing you'll probably do is upgrade the turbines to be bigger/more efficient. Then if you've maxed that out you can start adding solar panels underneath the turbines.

At the end of the day it's about lowering your costs to generate the power you need.

> Are we nearing any tipping point where local solar becomes a “big thing”?

Probably not, tbh. Its getting a lot cheaper, but its really possible that subsidies will start getting smaller along the same time. In my area, rules to force utilities to allow net metering on good terms are trending weaker as well. The combination hurts solar competitiveness.

If the cost of powerwall type systems fell by at least 50% some of these things might change, as the utility interconnect might not be needed any more.

Subsidies are in place to solve the chicken/egg problem of inducing demand and creating a new market. If solar panels are getting cheaper then subsidies should start to go away once targets are met. BTW, I still feel we're far away from withdrawing subsidies. Until we get below $1000/kw its still too steep for most homeowners. Currently, Florida is $2600/kw.

Oh, I agree and I have nothing against the subsidies getting scaled back over time. The issue is that it makes cost cutting in the industry less effective, as the savings don't always get directed to the buyer's bottom line.

I think it might create a long stall where solar doesn't really expand that much in consumer markets.

The utility interconnect really drives up the minimum price of solar because you have to go through licensed professionals who know you can't avoid them so there is no downward pressure on price unlike all other residential electrical (new construction notwithstanding).

I've noticed that effect, but I don't think the problem is on the installer side. A big part of the cost for them is the "soft costs" and a part of that is dealing with sometimes intransigent personnel at power companies. There are horror stories of them needing to pester the company for months to get the final approval to energize the system, and that adds significant cost. The solar companies would love to get rid of this problem.

I don't think that I'd want someone that isn't a licensed roofer or electrician doing the installation work anyway.

Do your homework on that. In many areas you can hire a solar guy to do your last mile for $600 to $1000. Everything else is DIY and Alibaba. Just make sure to get county approval on the inverters and UL listed etc...

Even where I live with a south facing roof and ample sunshine the pay off for a full system is something like 11 years - and after that I save $50/mo or some paltry amount. If it was reasonable I would get a small number of panels just to offsite the ToD pricing we have here (when the A/C needs to run the most) - but it seems that small installations are not cost effective in the end.