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> the utility will only let me put up a 4kW array due because they can't accept the extra energy and stay profitable.

Transmission congestion might be a more important issue than profitability: "Avoiding the congestion is essential for a competitive electricity market and is one of the toughest problems of its design." [1]

The course of Damien Ernst [2] gives an excellent overview of all the challenges related to decentralized electricity markets.

[1]: https://en.wikipedia.org/wiki/Transmission_congestion

[2]: https://damien-ernst.be/teaching/elec0018-1-energy-markets/

Yes this is major component of what I mean by profitability. The utilities spend vast sums on grid equipment and transmission lines that they pay for over decades through bond offerings. The grid is designed to distribute electricity from centralized generation stations to distributed customers (a "mainframe" like model). They support the capital cost of this infrastructure (debt payments) and maintenance on the equipment through their per kWH rates.

An example of this is that, where I live, some depreciated hydro assets produce power at $0.0025/kWh but the electricity rate is $0.11-0.14/kWh. It is not unusual for the majority of the cost of electricity be in debt and equipment maintenance rather than generation.

If I generate electricity on my roof then the utility is screwed from both ends, they must credit me way more than it costs them to generate their own electricity, and feeding electricity into a grid not designed for it adds further wear and tear to the components. Their revenue goes down and their costs go up.

Unsurprisingly, given their sunk costs and the prospect of defaulting on huge bond obligations, they will not permit me to install a rooftop array that will generate more than 40% of my usage, even if paired with large battery systems.

This. I worked for what in our deregulated market is called a "distribution company" (owning the transmission from the HV lines to the meter at your home), and can absolutely attest to what enslavedrobot has said. The funding model for getting electricity from A to B was predicated on assumptions that you could amortize the high capital costs over multi-decades. Which is all fine until distributed generation (rooftop solar) exploded in a time-frame much smaller than expected. Tbh my personal view is that the writing was on the wall large enough for anyone with eyes willing to see to start planning accordingly, but true to form, most companies just tried resisting the change.

I thought infeed limits were all about protecting the grid from power surges; what can an enlightened utility do differently? Battery storage would double the cost of community-generated solar, so even an enlightened utility might be unprofitable taking non-dispatchable power from homeowners, no?

Prices per panel may be dropping but that’s didn’t stop a major panel installer to quote me over $100k for 18kW system with two Tesla batteries. (The installer was not Tesla).

How can one take advantage of cheap panels and have quality work done on the roof?

A lot of it has to do with permitting, building codes, and lack of competition. In Australia deregulation has led to pricing well below 1AU$/W installed. If we could adapt what worked there prices would come down like crazy.

In Australia an 18kW system.installed with two 10kW/h Tesla batteries should run under $30,000 AUD installed. That's somewhere in the vicinity of $23,000 USD.

I've been looking at upgrading my rooftop solar in Australia, since we have had 5kW on the roof for close to 15 years now. Ill put away the pennies for a few more years and pull the trigger at a similar time to when we get our first EV / PHEV with V2G.

Interesting. I'm going off of what I've read and looking up quotes like these: https://www.solarchoice.net.au/commercial-solar/pricing/15kw...

Why is your system so expensive? Storage?

The new Tesla Powerwall 3 is $13,600

https://www.solarquotes.com.au/blog/powerwall-3-launch/

Two of those is $27,200 minus installation and some solar panels to feed them (but the PW3 does have 3x 6.6kW solar MPPTs built-in unlike previous ones, so all you need to do is connect the panels directly to the PW3 and then the PW3 to your home).

> How can one take advantage of cheap panels and have quality work done on the roof?

Teach your kids how the blue collar trades are a better deal than a college degree, wait a decade or two, and contractor labor prices should be reasonable again.

The 4Kw limit should be on the infeed and not the solar panel capacity. You could put 10Kw worth of panels up just limit the output to 4Kw. Now you have a more stable 4Kw feed.

Yeah, my dad has that setup. Over provisioned panels so he still can get max output more of the year. Not to the amount you suggest, but his inverter can safely have about 20% more input than output.

He bought used panels so the actual input may be a little lower than rated (though it doesn’t seem much lower), but he says he sees some ads for new panels nearly as cheap as he paid for used ones 5 years ago.

Is it or is it becoming profitable to have more power on the roof, but dedicated to local use? What local use? Local battery? Bitcoin mining? Aluminum plant (jk)?

Really hope to see battery technology making the same nosedives in price

With solid state batteries finally hitting production, I'm betting we'll see just that. The more common materials alone will make huge strides once scale-up pains are over

Do you have suggestions for the utilities on how to move away from a centralized grid, avoiding bankruptcy and also providing the same level of reliability as the last few decades?

The only supply side outage that comes to my mind is the Texas cold snap messing with the gas plants.

Perhaps neighborhood level energy storage and an increase in energy transmission costs.

It's very unlikely that a centralized grid will go away, society wants 100% energy availability 100% of the time. So like everything else, people are just going to have to pay for it. The same way you pay for schools even if you don't have kids or pay for roads even if you don't have a car.

It's a tough problem. Trillions of dollars of utilities bonds (mostly owned by pension funds) and a century of regulatory barriers make change hard. The problem is similar to the task of reforming the medical system.

The strategy that I like is to build out distributed systems in "non-integrated areas". These are locations that are not served by the grid and often have a tiny local grid that provides high cost electricity (~1$/kWh). These areas represent test beds for distributed energy tech and might be a place where de-costing and scaling strategies could be developed.

Another strategy is to wait for baby boomers to die. :)

With 4-5 MW batteries in the shape of shipping containers are already now available and rated for 6-10k cycles before much degradation. I think local neighborhood storage near consumption should become common in the near future. Of course electricity distribution companies etc will drag their feet specially in the US with their captured markets and near monopolies.

Do you have a link to an OEM with the 6-10k cycle spec?

State of the art moves quickly not long ago projects were budgeting for new batteries every 5 years in order to be able to meet energy guarantees