let's talk about battery banks- I reckon the "they aren't worth it" thing is wrong

[TommyO]

With net metering, you are not "selling kWh"- there is no monetary value put on the meter turning backwards. It is X number of kWh credit.

The monetary value is the price per kwh.
And with time-of-use and net metering in CA, since it's calculated on a $ basis it's fairly important.
But those are details that aren't really important for this discussion.

There IS a charge for getting it back when you exceed that credit.

IF you exceed that credit.
BUT often PV are sized so that they are large enough so that there is sufficient credit.
(And when there is kwh that have to be bought the *worst* case is that for those few kwh it's the normal purchase price per kwh, as if PV wasn't installed)

It is different when it is a kWh- the main reason why is that people don't consume houses, but they do consume kWh.

That the kwh is consumed afterward doesn't really affect it.
For all it matters I could be buying back the house to burn it down - doesn't change anything with the transaction does it?

The people hurt the most by this problem are those trying to offset their bills instead of have a zero bill- doesn't that describe the majority of residential PV?

How are they "hurt"?

If the array is sized that it doesn't generate enough kwh to cover the number of kwh used, it STILL isn't going to generate enough if you have batteries involved. (In fact because batteries have losses while net metering doesn't there's more kwh that have to be bought from the POCO)

 

[TommyO]

No, it isn't simple- you're only talking about systems where the daily PV output = 24 hour usage for instance.

No - net metering usually is based on a year.

You don't "get back" the actual energy you produce- you get a credit per extra kWh- that actual extra kWh goes down the street and someone else pays the POCO retail for it.

That it's a different kwh doesn't really matter - one kwh is the same as another.
Same thing as with dollars - if I give you 5 $20 bills and you give me back a $100 bill everyone views it as the same. Physically they're different - but they buy the same number of hamburgers.

A BESS stores the energy on site, and you use that same energy! Both the physical and financial processes are completely different with BESS.

Why would I care that it's stored on site?
What I'd care about is how I can get the power for my house for cheaper.

So then probably the amount of energy you'd use at night has no relation to the cost of BESS- it's always approximately a LOT OF MONEY.

Battery systems DO cost a lot of money.
Thousands of dollars.
Net metering costs $0 and provides the same benefits.

Let's compare them.

Battery system
* Costs $thousands
* Can send kwh's to the battery system
* Can get back ~90% of those kwh (Tesla says 92%, but other systems are much less.)
* Only short-term storage (days or maybe weeks)
* The energy is stored on site.

Net metering
* Costs $0
* Can send kwh's to the grid
* Can get back >99% of the kwh (some small loses in the wiring)
* Short to medium term storage (up to 1 year)
* Can take kwh out BEFORE sending the kwh in. (ex. use more kwh in spring, then get credits in summer)

Feel free to add any points where you think I missed something.
But given those things (mainly the first point in each list) I can't see why you'd want a battery system if you have net metering.

 

[PVfarmer]

But those are details that aren't really important for this discussion.
BUT often PV are sized so that they are large enough so that there is sufficient credit.

That the kwh is consumed afterward doesn't really affect it.
For all it matters I could be buying back the house to burn it down - doesn't change anything with the transaction does it?

If the array is sized that it doesn't generate enough kwh to cover the number of kwh used, it STILL isn't going to generate enough if you have batteries involved. (In fact because batteries have losses while net metering doesn't there's more kwh that have to be bought from the POCO)

That it's a different kwh doesn't really matter - one kwh is the same as another.

Battery systems DO cost a lot of money.
Thousands of dollars.
Net metering costs $0 and provides the same benefits.

Let's compare them.

Battery system
* Costs $thousands
* Can send kwh's to the battery system
* Can get back ~90% of those kwh (Tesla says 92%, but other systems are much less.)
* Only short-term storage (days or maybe weeks)
* The energy is stored on site.

Net metering
* Costs $0
* Can send kwh's to the grid
* Can get back >99% of the kwh (some small loses in the wiring)
* Short to medium term storage (up to 1 year)
* Can take kwh out BEFORE sending the kwh in. (ex. use more kwh in spring, then get credits in summer)

Feel free to add any points where you think I missed something.

I get it- the details aren't important! That's how you decide complicated financial investments.
Net metering is done the same way everywhere, and it is *always* the best way to do things, no point in complicating it with trivial details such as how much things cost or how much energy is being used.
KWh are kWh, and the prices for those aren't important either.
Storage has no effect on the economics of PV beyond being too expensive.

If you had anything to back those statements up, then there would be some issues.
Seems like you have an opinion and don't listen to things that don't agree with it basically.

All of the companies selling it as well as all of the analysts studying it are wasting their time, according to you.
Why so cynical?
---
Weiss has run some numbers on the battery storage option, and they are illustrated in the graph below. They are really only designed to be indicative. The consumption numbers are based on a large home with plenty of consumption, and some may disagree with the technology costs, both for solar PV and battery storage, which are evolving quickly anyway. The point is to provide a useful illustration for the choices that will be made, and for the critical debate about the shaping of our energy systems that must surely follow.

​

Based on these assumptions, Weiss crunches the numbers and works out that the sweet spot for a solar PV/Battery set-up is for a 5.3kW solar PV system that provides just enough power for 24 hours of household demand, and a 10.6 kWh battery capacity which stores surplus power to be used at night.
That means no import and no export. But there are several important caveats.
So long as the LCOE of solar PV is greater than the FiT (for exports to the grid), the best size for the solar module is the one that just supplies the house. If the LCOE is less than the FiT, then the sky is the limit.


http://reneweconomy.com.au/2013/how-battery-storage-will-change-household-energy-market-47946
---
Based on consultation with customers and leading suppliers, IHS is now producing the second edition of its ‘Energy Storage in PV’ report with a revised and enhanced scope. By utilizing IHS’ long experience of researching the entire PV industry, and its unrivalled research of the global energy storage market, this report will provide critical data and insight for understanding the development of this emerging market.
https://technology.ihs.com/461779/energy-storage-in-pv-2014

 

[ggunn]

No, it isn't simple- you're only talking about systems where the daily PV output = 24 hour usage for instance.

No, I am not. If your PV output over the course of a year (daily doesn't matter) is more than your usage, in many jurisdictions that have net metering you will lose the surplus at the end of the year no matter what. In others the utility will pay you a portion of the retail price per kWh for your surplus; few to none will pay you retail. Batteries won't make any difference. All batteries can do is time shift your usage and production, they cannot quantitively alter either except negatively because they are not 100% efficient. Grid storage, on the other hand, is 100% efficient.

Once again, the daily ratio of your PV production to your energy usage doesn't matter to net metering. Neither does the price per kWh from your utility. In most jurisdictions with net metering there is little to no incentive to building a PV system which produces more energy than you use in a year (daily doesn't matter), and, also again, batteries cannot change that.

I am probably going to regret this, but... What are your credentials? I am an electrical engineer (BSEE University of Texas 1986) with six years experience designing PV systems. I am a registered Professional Engineer and I have my own engineering firm in Texas. I am a NABCEP certified Solar Professional and I have designed over 4 MW of small to medium sized commercial PV systems in several different jurisdictions. I don't know everything there is to know about PV systems and electrical services, but I do know a few things.

Thanks for trying. That last part in italics sure isn't going to convince me of anything. I understand you have an opinion- I don't agree.
You don't mention anything I can really respond to.

Yes, it is simple (the minutiae you keep descending into is irrelevant) and nothing I said was opinion but fact. That two plus two equals four is not a matter of opinion.

Sorry; I said I was done. I am now.

Peace out.

 

[winnie]

In a discussion of your misunderstanding of _net metering_ you have thrown someone else's calculations for a situation where electricity costs 25.5 cents per kWh (that is what a price of $255/MWh means) and where the POCO pays 10 cents per kWh. (that is what FiT or Feed in Tarrif means).

The example that you give is explicitly _not_ net metering.

As has been stated numerous times: the economic worth of batteries to the customer depend on the specific POCO billing rules. It is pretty clear that you are either misunderstanding what net metering is, or you are intentionally being obtuse to yank our chain.

When you have net metering batteries can never be cheaper than using the POCO. It is that simple, because the rules artificially simplify the situation. With net metering the POCO provides a free virtual battery of effectively infinite capacity. As others have noted this virtual battery has some strange characteristics; for example it magically empties to 0 state of charge at the end of a billing cycle (or year). But for day to night energy storage it is large and free.

As as also been noted this virtual battery has some real costs for society, suggesting that perhaps 'net metering' is not really a good idea.

But net metering is the reality on the ground for many small customers.

-Jon

 

[PVfarmer]

If your PV output over the course of a year (daily doesn't matter) is more than your usage, in many jurisdictions that have net metering you will lose the surplus at the end of the year no matter what. In others the utility will pay you a portion of the retail price per kWh for your surplus; few to none will pay you retail. Batteries won't make any difference. All batteries can do is time shift your usage and production, they cannot quantitively alter either except negatively because they are not 100% efficient. Grid storage, on the other hand, is 100% efficient.

Once again, the daily ratio of your PV production to your energy usage doesn't matter to net metering. Neither does the price per kWh from your utility. In most jurisdictions with net metering there is little to no incentive to building a PV system which produces more energy than you use in a year (daily doesn't matter), and, also again, batteries cannot change that.

I am probably going to regret this, but... What are your credentials? I am an electrical engineer (BSEE University of Texas 1986) with six years experience designing PV systems. I am a registered Professional Engineer and I have my own engineering firm in Texas. I am a NABCEP certified Solar Professional and I have designed over 4 MW of small to medium sized commercial PV systems in several different jurisdictions. I don't know everything there is to know about PV systems and electrical services, but I do know a few things.

Yes, it is simple (the minutiae you keep descending into is irrelevant) and nothing I said was opinion but fact. That two plus two equals four is not a matter of opinion.

Peace out.

I just want to say that I am doing the best I can to be friendly- if it comes across as terse, well I'm busy AND I have a 5 year old nipping at my heels (literally) much of the time, so...

-
If your PV output over the course of a year (daily doesn't matter) is more than your usage,
in many jurisdictions
that have net metering you will lose the surplus at the end of the year no matter what.
In others the utility will pay you a portion of the retail price per kWh for your surplus;
few to none will pay you retail. Batteries won't make any difference.
-

"If your output is more..."...many...no matter what...won't make a difference.

You are leaving out the variables of output = to usage and output < usage.
Many jurisdictions isn't all..so how many?
No matter what? Where I am, with net metering you're allowed up to 25% over the usage in kWh credit, = to retail POCO rate, that you can "transfer" to any other account in your name. There are at least 5 different options, actually. Probably all 50 states are different.

See how I'm not reaching the same "won't make any difference" conclusion as you? I can't even really get started with your assumptions.

---
Once again, the daily ratio of your PV production to your energy usage doesn't matter to net metering. Neither does the price per kWh from your utility.
---

I don't see how you get that conclusion either. If PV output is too high, you give away energy, if too low, you still have a bit of a bill to pay.
These things matter -weather/local high-low temperature (different everywhere, even 5 miles apart if rural/urban...), day length/latitude...?

For instance- in New England, a net metered PV system (no BESS) with enough output to cover 100% usage in December/January (gets dark at 4PM) would basically be giving the POCO a *lot* of free energy in June/July/August!
That factor might be twice as bad in northern Maine as it would be in Bridgeport, CT. (Latitude)

That's great about all of your experience/credentials- you win. I'm not going to divulge anything, due to my state being VERY small (in fact the smallest), and beyond that...um..."rife with crony-ism" in short.
Or maybe ..."he said, she said" involves literally near 100% of the people in the state. It is both hilarious and tragic!

Anyway, just curious- if you had the PE first, why get the NABCEP? I've looked into it myself, and...there are all these "issues" in my state, which are almost nonsensical.
The PE I hired for instance- I'm not really concerned that he isn't NABCEP.
The most important thing to me is that my ME was a Navy electrcian for 20+ years and still has all his digits and limbs! :happyyes:

(the minutiae you keep descending into is irrelevant)

Um, no.
1. Geographic location/insolation/usage/customer goals
2. Price range target (customer's obviously)/available area for PV/POCO xfmr kVA + voltage/kWh needed (from usage in 1)
3. PV software (Helioscope/SAM is all you need there. Sunny Web Design is also fun)
4. A calculator and wholesale price lists.

So say you have 6 different projections from the 3 programs, comparing a pricey inverter vs a less pricey one, same panels.
6 different LCOEs sounds like "minutiae" to me!

 

[PVfarmer]

The example that you give is explicitly _not_ net metering.

As has been stated numerous times: the economic worth of batteries to the customer depend on the specific POCO billing rules.
It is pretty clear that you are either misunderstanding what net metering is, or you are intentionally being obtuse to yank our chain.

When you have net metering batteries can never be cheaper than using the POCO. It is that simple, because the rules artificially simplify the situation. With net metering the POCO provides a free virtual battery of effectively infinite capacity. As others have noted this virtual battery has some strange characteristics; for example it magically empties to 0 state of charge at the end of a billing cycle (or year). But for day to night energy storage it is large and free.

As as also been noted this virtual battery has some real costs for society, suggesting that perhaps 'net metering' is not really a good idea.

But net metering is the reality on the ground for many small customers.

Well, net metering is NOT the only case where batteries are used- even IF the "net metering makes batteries irrelevant" thing was true...that's nowhere near 100% of cases.
The economic worth of BESS is different for everyone.
"Net metering isn't the best way to use BESS" does not in any way mean that "BESS is not worth doing", even if it was true.

I understand what net metering is- is is 47 things in 47 different states!
The "virtual battery" is not free above a certain latitute- that latitude is different in every state it runs through.

I agree with you here- the worst thing about net metering may be that everybody just does it because it's "easy", but not necessarily "best"?

 

[iwire]

Well, net metering is NOT the only case where batteries are used- even IF the "net metering makes batteries irrelevant" thing was true...that's nowhere near 100% of cases.
The economic worth of BESS is different for everyone.
"Net metering isn't the best way to use BESS" does not in any way mean that "BESS is not worth doing", even if it was true.

I understand what net metering is- is is 47 things in 47 different states!
The "virtual battery" is not free above a certain latitute- that latitude is different in every state it runs through.

I agree with you here- the worst thing about net metering may be that everybody just does it because it's "easy", but not necessarily "best"?

Free storage is always cheaper than storage you pay for.

Will you at least concede that?

 

[TommyO]

For instance- in New England, a net metered PV system (no BESS) with enough output to cover 100% usage in December/January (gets dark at 4PM) would basically be giving the POCO a *lot* of free energy in June/July/August!
That factor might be twice as bad in northern Maine as it would be in Bridgeport, CT. (Latitude)

No.
A net metered PV system would normally be sized so that the total energy produced FOR THE YEAR is approximately equal to the total energy consumed FOR THE YEAR.

In June/July/August there would be extra kwh generated - more than are used each day.
And those credits would be used in Dec/Jan.
Of course with storms coming through there would probably be some days in summer where there wouldn't be extra kwh generated, and instead some of those credits would get used. But many days would have extra generated, and then the credits would get used in Nov/Dec/Jan.

Now an off-grid system - there you have to pay a lot more attention to seasonality since they just aren't going to do multi-month storage.

The "virtual battery" is not free above a certain latitute- that latitude is different in every state it runs through.

What do you mean a certain latitute?

We've gone through calculations in 2 states so far that YOU have picked - California and Maine. For both of them the net metering is free and applies to the entire state.

 

[TommyO]

The economic worth of BESS is different for everyone.

Absolutely true.
In some countries it can save you money.

And in the US the economic impact of adding batteries varies from state to state and location-to-location as well. For example, in places with no POCO lines nearby, it can be a lot cheaper than paying for a new powerline. While in places like Maine and California where there's already a hookup to the grid, there would be zero payback from the extra expense.

 

[winnie]

Well, net metering is NOT the only case where batteries are used- even IF the "net metering makes batteries irrelevant" thing was true...that's nowhere near 100% of cases.
The economic worth of BESS is different for everyone.

Absolutely true.

The economic worth of energy storage is different depending on the specifics of the installation and the applicable billing rules.

The billing rules distort costs, so even if in a particular situation energy storage makes sense from one perspective, the energy storage may not make sense from the perspective of the person paying out the dollars.

"Net metering isn't the best way to use BESS" does not in any way mean that "BESS is not worth doing", even if it was true.

I understand what net metering is- is is 47 things in 47 different states!
The "virtual battery" is not free above a certain latitute- that latitude is different in every state it runs through.

You have yet to come up with a scenario where the 'net metering virtual battery' costs more than a real battery, except when you make math errors. A real battery is only economically viable to the person putting the cash out in situations where there is not net metering.

In locations where 'net metering' applies to an entire year cycle, not only is the virtual battery cheaper than a real battery, it is also much larger, which means you can have a _smaller_ PV system. When 'net metering' applies over a full year, then energy generation in the summer months can supply the winter months. Consider the size of a real battery system needed to do this!

-Jon

 

[PVfarmer]

Free storage is always cheaper than storage you pay for.
Will you at least concede that?

Sure, if you'll concede that storage that you pay for can (and should) eventually become free! :happyyes:
Just like PV with no BESS should.
So then what happens?
Wouldja care to share any thoughts on my "above a certain latitude" theory as regarding net metering vs. BESS?

No.
A net metered PV system would normally be sized so that the total energy produced FOR THE YEAR is approximately equal to the total energy consumed FOR THE YEAR.

In June/July/August there would be extra kwh generated - more than are used each day.
And those credits would be used in Dec/Jan.

It would only "normally be done" if the person had the $$ to pay for it!
If someone used 30kWh a day 24/7/365, and could only afford a 20kWh a day output system...with an LCOE of 10 cents...
And that person paid 15 cents/kWh to POCO....they'd still have a $547.50 a year bill.
Would that be good in comparison to spending 5 cents/kWh on BESS and having no bill? Better or worse? (trick question)

What do you mean a certain latitute?

We've gone through calculations in 2 states so far that YOU have picked - California and Maine. For both of them the net metering is free and applies to the entire state.

So how many BESS systems are already installed in each state? Total AND per capita? That would interesting to know..
Higher latitude = shorter days in winter, less sun. This affects PV output and therefore PV economics.
Right? And optimal size of BESS of course!!

Originally Posted by PVfarmer

The economic worth of BESS is different for everyone.

Absolutely true.
In some countries it can save you money.

All of them in fact. All countries have them installed and in use.They've been used in the USA since the 70s.

And in the US the economic impact of adding batteries varies from state to state and location-to-location as well. While in places like Maine and California where there's already a hookup to the grid, there would be zero payback from the extra expense.

That's still an opinion you have.

Absolutely true.

The economic worth of energy storage is different depending on the specifics of the installation and the applicable billing rules.

The billing rules distort costs, so even if in a particular situation energy storage makes sense from one perspective, the energy storage may not make sense from the perspective of the person paying out the dollars.
You have yet to come up with a scenario where the 'net metering virtual battery' costs more than a real battery, except when you make math errors. A real battery is only economically viable to the person putting the cash out in situations where there is not net metering.

In locations where 'net metering' applies to an entire year cycle, not only is the virtual battery cheaper than a real battery, it is also much larger, which means you can have a _smaller_ PV system. When 'net metering' applies over a full year, then energy generation in the summer months can supply the winter months. Consider the size of a real battery system needed to do this!

I cited one in the OP:
"When the cost of the PV+BESS is < than the POCO rate".

Why would you bother net metering if you could get a system that produced 100% of your usage for less than the grid price?

Change it to "when cost of (PV + BESS ) MINUS any financial incentives is < POCO rate"...
Golly- that sure happens!

 

[TommyO]

It would only "normally be done" if the person had the $$ to pay for it!
If someone used 30kWh a day 24/7/365, and could only afford a 20kWh a day output system...with an LCOE of 10 cents...
And that person paid 15 cents/kWh to POCO....they'd still have a $547.50 a year bill.
Would that be good in comparison to spending 5 cents/kWh on BESS and having no bill? Better or worse? (trick question)

Yes, that's a trick question.
If they spend $.05/kwh on batteries they STILL have the same POCO bill.
(And in addition they have the added expense of those batteries which aren't providing them any benefits they don't already get from net metering)

"While in places like Maine and California where there's already a hookup to the grid, there would be zero payback from the extra expense."

That's still an opinion you have.

You can call it an opinion, but the math shows that is quite clearly the case.
You obviously don't want to believe it, but that's what the math clearly shows.

I cited one in the OP:
"When the cost of the PV+BESS is < than the POCO rate".

I thought we had already explained to you that wasn't true in a place with net metering.
Remember about 15 posts ago where we went through scenarios A, B, & C?
And Scenario B (PV-only) ALWAYS won?

Why would you bother net metering if you could get a system that produced 100% of your usage for less than the grid price?

Because I can use net metering for free and get the same result ($0 utility bill) FOR LESS MONEY.

 

[winnie]

You have yet to come up with a scenario where the 'net metering virtual battery' costs more than a real battery, except when you make math errors. A real battery is only economically viable to the person putting the cash out in situations where there is not net metering.

I cited one in the OP:
"When the cost of the PV+BESS is < than the POCO rate".

That is an incorrect statement for net metering! It applies to the situation where you get no credit for excess energy exported during the day.

You have been shown that the statement is wrong and you keep repeating it.

In general you want to use a BESS when:
LCOE of PV + 'LCOS of BESS' < POCO charge per kWh + LCOE of PV - POCO credit per kWh
which simplifies to
'LCOS of BESS' < POCO charge per kWh - POCO credit per kWh

You keep leaving out the _credit_ that you get when you supply energy to the grid.

Now: if you get zero credit for supplying energy to the grid, then a BESS might make sense.
If the POCO charges you more for energy that you buy then it pays when you sell, then a BESS might make sense.
But with 'net metering' the POCO rate does not matter because the meter credits you for excess energy produced during the day, so you do not get charged when you use it at night.

Why would you bother net metering if you could get a system that produced 100% of your usage for less than the grid price?

Because:
PV + BESS must always cost more than
POCO rate + PV - POCO rate
the cost and the credit cancel out!

Even if you 'fully depreciate' the system and the PV array is free and the BESS is free, you still do better exporting the PV to the grid and using the grid for storage (assuming 'net metering')

-Jon

 

[PVfarmer]

you-
"While in places like Maine and California where there's already a hookup to the grid, there would be zero payback from the extra expense."
me-
That's still an opinion you have.
you-
You can call it an opinion, but the math shows that is quite clearly the case.
You obviously don't want to believe it, but that's what the math clearly shows.
----
I thought we had already explained to you that wasn't true in a place with net metering.
Remember about 15 posts ago where we went through scenarios A, B, & C?
And Scenario B (PV-only) ALWAYS won?
---
Because I can use net metering for free and get the same result ($0 utility bill) FOR LESS MONEY.

"in a place with net metering"

See, that's the problem- WHAT PLACE? Who? Where? How much electricity do they use?
You just keep making the same statement with no specifics whatsoever.

9% isn't enough for you?

Attached Storage To Accompany 9% Of Solar PV In North America, IHS Reports

“Incentives, like the Self Generation Incentive Program offered in California, are also making the economics of such systems extremely attractive; but there is no guarantee that electricity tariff structures won’t be adjusted, which could affect the economics of existing systems,” Wilkinson added.
http://cleantechnica.com/2015/03/16/attached-storage-accompany-9-percent-solar-pv-north-america-ihs/

Scenario B only won your way of doing it. Remember how your way was wrong?

And you CAN use net metering to get a zero bill- remember two comments ago? Not everybody does that.
You yourself could net meter and get a zero bill OR do the same with BESS, for the SAME price! Different equipment and systems of course.

 

[PVfarmer]

In general you want to use a BESS when:
LCOE of PV + 'LCOS of BESS' < POCO charge per kWh + LCOE of PV - POCO credit per kWh
which simplifies to
'LCOS of BESS' < POCO charge per kWh - POCO credit per kWh

POCO charge per kWh minus POCO credit per kWh...

Doesn't that always equal zero with net metering?
There is no $ value on the POCO credit. There is no payment on that credit, it's just 1 kWh.
So if kWh/PV out to POCO > kWh consumed, you are "generating credit" for no reason.
If kWh/PV out to POCO = kWh consumed, you are net metering.
If kWh/PV out to POCO < kWh consumed, you are paying an inflated price for energy from a "free battery".

That could be daily, monthly, yearly, or lifetime.

 

[TommyO]

"in a place with net metering"

"See, that's the problem- WHAT PLACE?"
California or maine for starters.
You suggested those two, and we've looked at them in depth already.

"Who?"
A residential user hooked up to the power company.

"Where?"
CA, Maine, and other places with similar net metering.

"How much electricity do they use?"
Can be 1kwh/day, 10kwh/day, 100kwh/day - all the residential customers are under the same net metering rules, so net metering is free whatever the amount.

9% isn't enough for you?

That's 9% projected by 2018 AND if you look at the graph you can't see ANY residential in 2014 - maybe there's some in 2015, but it's fewer than 10MW across NA.

Scenario B only won your way of doing it. Remember how your way was wrong?

Remember how you thought it was wrong, but I actually had it correct and showed that you had made mistakes in your calculations?

You yourself could net meter and get a zero bill OR do the same with BESS, for the SAME price! Different equipment and systems of course.

No - I can't get the same quality equipment AND batteries for the same price.
Batteries are $thousands.
So either you have to buy cheaper (lower quality) equipment OR you have to buy less equipment for a given budget (ex. fewer panels, smaller inverter).

 

[ggunn]

How are things going with that windmill, Mr. Quixote?

Give it up, guys. He's never going to see it. Either that, or he sees it and he's never going to admit it.

 

[TommyO]

POCO charge per kWh minus POCO credit per kWh...

Doesn't that always equal zero with net metering?
There is no $ value on the POCO credit. There is no payment on that credit, it's just 1 kWh.
So if kWh/PV out to POCO > kWh consumed, you are "generating credit" for no reason.

In CA you get paid a small amount for the excess generation that you didn't consume in that fiscal year.
Other states could treat it differently.
But with net metering it is possible to get a small check back from the POCO for excess power generated.
Usually the payment per kwh is close to the PV LCOE, so you don't want to generate a whole bunch extra.

If kWh/PV out to POCO = kWh consumed, you are net metering.

All 3 of these are still called net metering.
This is usually the target which you want to hit since it is the most beneficial to the PV buyer.

If kWh/PV out to POCO < kWh consumed, you are paying an inflated price for energy from a "free battery".

No - you are paying the SAME price as your neighbor does.
For example, lets say at the end of the fiscal year you generated 11000kwh but consumed 12000kwh.
And your neighbor uses 1000kwh each month just like you.
You now have a bill for $.15*1000 ($150) for the entire year.
And your neighbor has a bill of $150 each month.

Sure you had to pay $thousands for the PV array to reduce your power bill by ~90% - but the savings in the electric bill pays for that up-front expense in 4-10 years.
If you add a battery system, you now have additional costs to build the system but it doesn't reduce your bill with the POCO any. Therefore it adds extra time before your savings in POCO bills pay for that extra expense.

 

[PVfarmer]

How are things going with that windmill, Mr. Quixote?

Give it up, guys. He's never going to see it. Either that, or he sees it and he's never going to admit it.

Seriously? You wanna start talking about WIND POWER now?

That's a joke.

Hey, ever seen one of these things before? Just wondering how pricey they are.
Usually if there isn't a price, it's MORE than you think it'll be.
Is this a $150 thing or a $750 thing? Best guess? I'm thinking $200 tops.

http://www.synqor.com/Datasheets/NQ90W90QTx18_Datasheet.pdf

Therefore, the key advantages of this design are: the ability to choose the constant output voltage and current, the procedure is simple, the converter and controller has a simple structure, improved efficiency – up to (96.55%), reduced output ripple voltage-less than (11mV), the complete converter circuit is small and inexpensive, and finally, the designed converter circuit topology operates effectively for different input and output operating conditions. So, the procedure outlined in this paper can be easily adopted for buck-boost converter. It is, therefore, feasible for common solar DC-DC conversion applications.
http://www.academia.edu/9447263/Des...rter_for_Photovoltaic_Solar_Home_Applications

Oh why not- check THIS out!
http://cleantechnica.com/2015/05/01...adeless-micro-wind-turbine-gets-harvard-cred/