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Solar panels reduced my electric bill in 2022

mattbruenig.com

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Re: Solar panels reduced my electric bill in 2022

#451

Post by amluto »

eppp wrote: post #234
amluto wrote: post #149

Earlier quoted context omitted.

This is all rather bizarre. If PG&E charges 30 cents/kWh for a marginal kWh delivered, then either something is quite wrong with the pricing model or it really does cost some respectable fraction of 30 cents/kWh to get a marginal kWh through their system into their distribution network where the customer is. If it's the latter, then reduction of 1 kWh delivered should save them the same amount of money. I think the r…

The issue is that you have to size the hardware for a multiple of the power draw you expect and the cost doesn't go down because people use less temporarily. You also have to do all the vegetation management and billing and it and billing regardless of the amount of kWh that are used even if a solar install is negative. They might draw today and it has to be available.

> They might draw today and it has to be available.

This is true for non-solar customers too. It may be more true for solar, but unexpectedly high residential loads happen for all kinds of reasons. (A big one is heat on a very cold day, and that tends to be a correlated load.)

Re: Solar panels reduced my electric bill in 2022

#452

Post by edmundsauto »

Nathanael_M wrote: post #39

Does anyone have any detailed, up-to-date resources for personal solar use? I'd love to learn more, in particular the cost/output/lifespan progress by time. Last time I checked in my area it seemed that you didn't quite break even, but that was a while ago and my understanding was/is very limited.

It's fragmented information due to so much lead gen content out there, which is of course all very rose tinted. /r/solar is a decent community.

Re: Solar panels reduced my electric bill in 2022

#453

Post by amluto »

secabeen wrote: post #164
amluto wrote: post #149

Earlier quoted context omitted.

This is all rather bizarre. If PG&E charges 30 cents/kWh for a marginal kWh delivered, then either something is quite wrong with the pricing model or it really does cost some respectable fraction of 30 cents/kWh to get a marginal kWh through their system into their distribution network where the customer is. If it's the latter, then reduction of 1 kWh delivered should save them the same amount of money. I think the r…

Reduction of 1kWh delivered does not save them the same amount of money because the cost of connection is dominated by the 1st kW delivered. Scaling delivered power does have some cost, but the majority of delivery is in being able to deliver power to a particular area in the first place and to the maintenance of the lines providing any power.

Yes and no. If I draw an extra 10 kWh one random hour and export 10 kWh back at some other random hour, this costs the utility essentially nothing. The transformer is already there, and other customers near me will consume it possibly without even involving the transformer.

(I say “essentially” because there is some tiny loss in the system, but that’s maybe 2%, not 70%.)

Re: Solar panels reduced my electric bill in 2022

#454

Post by maxerickson »

grecy wrote: post #423
zombielinux wrote: post #272

Earlier quoted context omitted.

The problem is that its not a DC connection to the grid. Not only do you have to match voltage on re-connection, but you have to match frequency AND phase. Its "doable" but to do so reliably without a stable reference can be challenging. That's why the DC requirement is there. They want some form of reliable power to well tested electronics to match phase and frequency when the grid comes back up. A heavily loaded AC…

I've read that before, and I have a further question if you could indulge me What if, when the grid goes out the inverter keeps powering the house (and disconnects from the grid). Then when the grid comes back on, kill the output of inverter (which results in outage to the house), reconnect to grid, then power up the inverter again, which skirts all the sync issues. The house will see a few second outage... but it wi…

The overall problem is more or less solved, it just adds equipment to the installation, both to make the power usable and also to ensure that it is isolated from the grid.

Re: Solar panels reduced my electric bill in 2022

#455

Post by hbarka »

FartyMcFarter wrote: post #373
dpierce9 wrote: post #350

Earlier quoted context omitted.

Net metering means utilities sell the power your system produces at full price to your neighbor. They pocket the avoided cost of producing and delivering that power (and during price spikes the cost of fuel can be higher than the value of producing power). Net metering does create stranded assets if everyone does it. But not everyone does. Further, the idea that the utility gains NO benefit from net metering is wrong…

Net metering doesn't make sense for a simple reason: - when you use power, the grid is forced to produce it for you at that specific moment. - on the other hand, solar panels produce energy at random times, regardless of whether it's needed or not. Net metering forces symmetric pricing into a fundamentally asymmetric situation, which is not scalable. You could think of similar asymmetries in other contexts where the…

Analogies are terrible but I’ll bite—

Imagine if you will there’s a peak demand for pizzas (dunno maybe Super Bowl?) and the pizza company is struggling to deliver enough pizzas. You come in and say hey Mr Pizza Company I’ll help out with that demand and make pizza for you, and so will my other neighbors and we’ll help you supply pizza. Mr Pizza Company takes your pizza and sells it but only pays you a fraction of what they charged their customers. And on top of that charges you for making pizza for them. This is what you get in return. Except you’re making pizza everyday and giving it to the pizza company so they can sell your pizza out in the market first before they sell theirs. The greatest trick played.

Re: Solar panels reduced my electric bill in 2022

#456

Post by encoderer »

lostlogin wrote: post #363
encoderer wrote: post #182

Earlier quoted context omitted.

Asphalt singles

Is there a reason that corrugated iron, concrete tile or similar aren’t used? They last near indefinitely if looked after, and a hell of a long time if not looked after.

They are very cheap.

Re: Solar panels reduced my electric bill in 2022

#457

Post by TMWNN »

TMWNN wrote: post #436
RC_ITR wrote: post #405

Earlier quoted context omitted.

Oh fun! I love when people Dunning-Kruger themselves on accounting (I literally just sat up straight in my chair!) Let's go through your argument (would you believe I did both read and understand the document I linked!?), but before we do that, let's look at some more traditional subsidies that O&G gets in America: [0] The GAO has reported extensively that taxpayers have not received a fair rate of return due to outd…

>Underpriced use of public land sure sounds like a subsidy to me! I have no problem with raising lease rates for Federal land to market rates. >>US gas is cheaper than elsewhere in the developed world because a) the US is self-sufficient in terms of supply >Oh, I was unaware that the cheap gas phenomenon started in 2008 when we started approaching energy independence. Thanks Obama, I guess. Oh, come now. It is a fact…

EDIT to above: I, of course, shamefully erred in basic arithmetic. 135 billion gallons of gas and $4 billion in "subsidies" means ~$0.03 per gallon, not $0.34. Only reinforces my point of course by a factor of ten, of course, but still quite embarrassing.

Re: Solar panels reduced my electric bill in 2022

#458

Post by akira2501 »

Kirby64 wrote: post #356
akira2501 wrote: post #241

Earlier quoted context omitted.

I don't find his methods particularly rigorous. He's just taking total generated kWh and multiplying it by current utility rates and then saying this represents savings. Does it, though? We don't know how much of the generated power was actually used instead of sold back into the grid, or if this is even a grid tied installation, and what the return sales rate would be. The only way to actually compare this is to loo…

If you live in a place that does net metering, it truly just is as simple as generated kWh * utility rate. That's what net metering means. Each kWh you provide via solar offsets the cost of a kWh from the grid. Additionally, if you live in a place where power is $0.20-$0.30/kWh, then $233/mo is not a particularly large amount of electricity, especially for a single-family house. At $0.30/kWh, that's only ~775kWh of e…

There are a few different forms and a few different rules surrounding it. I can probably assume what he means, but a more direct comparison would obviate any of these factors.

Right.. but that's not his total cost, that's his total savings. So, with those factors; which make sense for New England, he's got a 7kW system getting light for about 3 hours a day on average to net that 775kWh to earn the $233 savings in a month. Would that be right?

Re: Solar panels reduced my electric bill in 2022

#459

Post by zo1 »

kibwen wrote: post #221
shostack wrote: post #137

Earlier quoted context omitted.

Is net return all that matters? Seems like with increasing heat waves, power outages etc, being able to generate and store your own electricity has value from a resiliency standpoint.

Note that merely having solar panels on your house doesn't automatically let you run your house off of the panels in the event that the grid goes down. Firstly, if you're connected to the grid, then a single house trying to push power into a downed grid would be like trying to refill the ocean with a super soaker. Even with lots of houses doing it, the frequency would be wildly unstable at best and cause damage to eq…

I'm not sure what kinds of hardware you guys have seen or been marketed. But from my pov, these are all pretty standard features of most hybrid inverters and come out of the box. The only extra expense to not be grid tied is needing a battery and maybe a tiny amount of extra electrical wiring. It wasn't even a question that popped up during my build.

Then again, we regularly have huge rolling blackouts here so we need the inverter to be a giant UPS for the house and be able to use solar and grid at the same time.

Re: Solar panels reduced my electric bill in 2022

#460

Post by dbetteridge »

iamthemonster wrote: post #406
dbetteridge wrote: post #401

Damn, solar panels are expensive in the USA... In Australia a 6.6kw system with 5kw inverter runs about 3500-4500AUD installed and grid connected. The rebates in WA are fairly low for exported power (about 5c/kwh) but you can fully offset your usage during the sunny parts of the day running aircon/washing machine.

The price has gone up of late, you are probably looking 4000-5500 depending on inverter quality (that's based on 2023 STCs) But that said, Western Power's inflexible blanket ban on any feed-in above 5kW (single phase) has had a wonderful side benefit of enabling solar companies to be ultra competitive with the 6.6/5 kW system installs because basically everybody wants the same equipment, allowing much greater standar…

Fair point, I was going off 2022 prices.

Yeah it makes sense that a limitation like that forces competition, along with cheaper import costs from China I imagine not hurting.

30c/kWh is not really cheap by most countries standards, especially when you really need aircon during summer and from this year can't build a new home with gas heating or cooking in WA.

Going to be an interesting few years I think as grids start to move away from coal base loads en-mass

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