[kalessin]

I don't really understand the idea of micro-grids, how do you account for redundancy, or long term storage if inclement weather goes on for a few days? Do you just keep big fossil gas generators as backup? Moreover residential is one thing, but industrial is another.

[KennyBlanken]

There are a bunch of existing spreadsheets that allow you to estimate sizing of the panels and batteries.

You couple that with maps that show 'full hour equivalency' figures for your area, and add in how much extra reserve you want, using calculations based off "I want the system to handle X days of no solar" and "I want the system to be able to charge back to full, given typical household load, within Y days."

A number of folks with off-grid systems have backup generators for the odd "two weeks of rain" situation or a failure of part of the system.

It ends up being fairly efficient because you can size the charger to almost fully load the generator. A fridge uses about 1kWhr/day, which is about 15 minutes of a 3kW generator running...

[Scoundreller]

I just want some big fridge/freezer manufacturer to build a "green fridge" with a 24-48VDC port and include a ~100W panel that anyone could wire up. Auto-switch to 120VAC as needed. Newer fridges run a variable drive motor, so the circuitry required has gone down.

[epistasis]

With microgrids, you have multiple days of storage. Maybe you have emergency backup generators, but that's unlikely. There's a cost tradeoff between extra solar capacity (on cloudy days you still get energy, after all) versus the cost of storage. It's all solvable, just takes money. As transmission would. And often, 3+ days of battery storage is going to be a looooot cheaper, particularly at the load levels that a lot of microgrids will see.

Though I don't think developing areas will necessarily have large industrial needs, it turns out that industrial can be easier than residential if most of the industrial need is process heat. Because we have super super cheap tech for storing high amounts of heat for many many days. Lots of storage startups are exploring this space now.

Having multiple days of battery storage is 5-15x more expensive than thermal storage at the moment, IIRC.

[RetroTechie]

Storage may not even be needed. Or be very small compared to what's used elsewhere.

Eg. the boats mentioned in article: if their 'solar roof' is big enough, and they're only used during daylight hours, they might be run without any batteries. Simply PV panels -> converter -> motor.

Likewise, some activities that use more power could be limited to those hours where solar power is plenty.

On a large AC grid it's difficult to control the consumption side. But on a small/local grid (or single-building setups), much easier: short lines between producers & consumers - literally.

[turtlebits]

You just fall back to whatever use used to generate power before solar. From the article, it's gas generators. If you have money, battery storage.

[dtgriscom]

You have to balance the cost of providing continuous, reliable power against the cost of losing power once in a while. The more flexible you are in your needs, the easier you can work around losing power and the cheaper you can make your power/storage system.

[Waterluvian]

I think it should make sense if you compare it to the alternative: nothing at all.