Cost. Useful life. I thought about an off grid system. Batteries are expensive. Also, unless you live in a dry place in the equator, You'll need to account for things like winter, long rainy spells, so either you add more batteries to account for multiple days (weeks? months?) of low generation, or you'll need a diesel/gas generator, or have a hybrid system instead, which basically means you're using the utilities gas generator instead.

Then, subsides are drying up. Systems have a useful life, your panels can be damaged by storms, for maximizing battery life you need to ensure you don't discharge it below 20%, and neither charge it over 100%.

So, in the end, the grid needs to be there anyway, but as most grid costs are fixed, whenever you use it now, it is going to be more expensive.

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fpoling 4 hours ago | parent | next [-]

There was an article that described that in UK one needs 1 megawhat-hour battery over the winter to be grid independent. Judging by current trends in few years that will be below 40K USD. While this is indeed very expensive in most of US due to much more sun available the required battery would cost below 20k. One can also have a backup generator that can run constantly at maximum efficiency to replenish the battery. Then the whole system can already be below 20K. While expensive, it provides true independence and I suspect grid cost and centralized power is more expensive for society.

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ViewTrick1002 3 hours ago | parent [-]

These studies tend to always rely on a perfectly balanced grid without any extra capacity to find these massive seasonal differences.

Add a bit of extra capacity to the wind/solar installations and the battery figures usually plummet.

	▲	phil21 an hour ago \| parent [-]
		This is for a single home off-grid, meaning solar over-production is already implied. You need enough solar available to charge that 1MW battery in time for it to be useful during those seasonal differences which is going to be multiples of your peak summer generation.

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evolve2k an hour ago | parent | prev | next [-]

No need to go off grid. You getting solar and battery already positions you to be able to ‘exit the grid’. The experience in Australia has been that the major retailers keep charging infrastructure costs to those who still rely on them. The mass of solar adoption grid and off-grid shifts the playing field.

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raddan 4 hours ago | parent | prev | next [-]

Generating your own power does not necessarily mean cutting ties with the grid. I think for most people in most places being off-grid would be a real challenge. I’m not sure how Australia does it but in my neck of the woods (northeast US) staying grid-tied is the norm.

I have a relatively big battery (12kWh) which is enough to see me through the evening during the summer months. We do not get quite enough sunshine where I live to be off-grid during the winter, but I can use the battery to hedge against grid outages which are common here in the winter due to storms (eg heavy ice taking down power lines).

	▲	thijson 4 hours ago \| parent \| next [-]
		The battery in the winter could be used to charge during low cost time periods, assuming your have time of use energy prices. I see people in the UK doing that all the time because the peak prices are very high. I think California is the same. Batteries have come down a lot in cost, at least the raw ones: https://youtu.be/3mAx_KE8gz0 Without the tariffs it would be even cheaper I guess.
	▲	dgacmu 3 hours ago \| parent \| prev [-]
		We do the same in Pennsylvania - I have about 10 kwh of battery. I can't put solar on my roof, so I only have a very small 800w array on top of my garden. I run it as an off grid system that can recharge from shore power, so I have to use all of the energy it produces or it goes to waste. But it saves some money and is enough battery to let me time shift to take advantage of time of use power rates, and it gives me very good run time for refrigerators and internet during outages. There seem to be a few sweet spots in solar - a tiny array that you use all of without having to grid tie it is really cost effective. (The cost of grid tied solar adds 5-10k to the system cost). Otherwise go big. :)

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evolve2k 4 hours ago | parent | prev [-]

From what I’ve been reading, sodium ion batteries are about to land later this year and look set to drop costs upwards of 60%.

That and they can be cold booted and stand much more temperature diversity bitter and into frozen temps too.

Just saying, the tech and solar expansion is at run away global growth right now, despite American centric machinations.