Buy all, sell all

[ggunn]

If their power is worth $X per kWh, why isn't mine? I have to cover the costs of fuel and infrastructure, too.

Of course you do, and if/when you are doing the math to decide whether or not to buy a PV system, you need to put that on your side of the ledger.

 

[electrofelon]

I just wanted to make one more point. If you were to buy some land, put a PV system on it, and approach the POCO to sell them power from your system, you'd have to negotiate with them as to what they'd pay you for it. They certainly wouldn't pay you what they charge their customers; in fact, I'd wager that it would be a whole lot less than Austin Energy's VOS rate. If you have a system behind your meter, from the POCO's POV, what's the difference? You are consuming energy somewhere; what difference does it make which meter it's passing through?

Austin Energy is very pro-solar; they have, IMO, struck an effective balance in a complex environment of desires and priorities. AE's Board of Directors is also the Austin City Council; there are political realities they have to consider and after all, this is Texas <wink>.

Well back at you: what difference does it make if I reduce my power consumption with a pv system versus changing out an electric heater to a gas one, or just don't turn things on? POCO doesn't still charge me a few cents for things I'm not using...

 

[ggunn]

Well back at you: what difference does it make if I reduce my power consumption with a pv system versus changing out an electric heater to a gas one, or just don't turn things on? POCO doesn't still charge me a few cents for things I'm not using...

You aren't reducing consumption, you are pumping energy onto the grid to compensate for it. That has a different effect on the grid; not so much as you would notice, personally, but from the POCO's POV when hundreds of thousands (or millions) of people are doing it, it's significant. With solar and wind getting to be bigger players on the grid, management of their effects are getting to be quite challenging.

And before you say that it's only your household load you are affecting, that's not so. It's a massively parallel system; everything is connected to everything else. Yes, the effect of your personal contribution is minuscule, but the cumulative effect of all those systems is not.

And all that is ignoring the fact that you are setting yourself up as a competitive supplier of energy and you are depending upon the POCO owned and managed infrastructure to enable it. From their POV it makes no difference whether you are supplying energy to yourself or to your neighbor, and to some extent you are supplying power to your neighbor. Again, it's a massively parallel system. Putting power on the bus is not the same as reducing what you are drawing from it.

 

[GoldDigger]

I guess one practical difference between self-consumption and equal consumption and production comes when the load has a low power factor. Older grid interactive inverters cannot be configured to deliver power at other than PF = 1.
So POCO would be supplying only the reactive current. That would not make them happy if it got to be too large a part of base load.

Sent from my XT1585 using Tapatalk

 

[jaggedben]

You aren't reducing consumption, you are pumping energy onto the grid to compensate for it.

You can't use that language to describe it if you want to claim there's no difference between exports and self consumption.

That has a different effect on the grid;...

Exports have a different effect on the grid than self-consumption. Self-consumption doesn't have a very different effect on the grid than reducing consumption.

ot so much as you would notice, personally, but from the POCO's POV when hundreds of thousands (or millions) of people are doing it, it's significant. With solar and wind getting to be bigger players on the grid, management of their effects are getting to be quite challenging.

It seems to be less challenging than some naysayers predicted in the past.

rom their POV it makes no difference whether you are supplying energy to yourself or to your neighbor, and to some extent you are supplying power to your neighbor. Again, it's a massively parallel system. Putting power on the bus is not the same as reducing what you are drawing from it.

From the utilities POV regarding resources they have to supply, it makes no difference whether you supply enough power for yourself and a couple other homes, or whether all three homes turn off their service disconnects for a while. From a financial standpoint, however, they are different; they still get to charge the other two homes full price when you export your solar.

 

[jaggedben]

I guess one practical difference between self-consumption and equal consumption and production comes when the load has a low power factor. Older grid interactive inverters cannot be configured to deliver power at other than PF = 1.
So POCO would be supplying only the reactive current. That would not make them happy if it got to be too large a part of base load.

As you may know, in California we now have to implement certain power factor features for new net-metering applications. (Look up UL1741-SA and Rule 21.) It seems to me that it's turning out that DG inverters are rather adept at responding positively to adverse grid conditions. There are even companies working to aggregate residential storage resources to provide grid services. These kinds of things make ggunn's line of reasoning quite a bit less persuasive to me.

 

[electrofelon]

You aren't reducing consumption, you are pumping energy onto the grid to compensate for it. That has a different effect on the grid; not so much as you would notice, personally, but from the POCO's POV when hundreds of thousands (or millions) of people are doing it, it's significant. With solar and wind getting to be bigger players on the grid, management of their effects are getting to be quite challenging.

And before you say that it's only your household load you are affecting, that's not so. It's a massively parallel system; everything is connected to everything else. Yes, the effect of your personal contribution is minuscule, but the cumulative effect of all those systems is not.

And all that is ignoring the fact that you are setting yourself up as a competitive supplier of energy and you are depending upon the POCO owned and managed infrastructure to enable it. From their POV it makes no difference whether you are supplying energy to yourself or to your neighbor, and to some extent you are supplying power to your neighbor. Again, it's a massively parallel system. Putting power on the bus is not the same as reducing what you are drawing from it.

I think JB addressed this, but you seem to keep talking about putting power into the grid. My POV is that I should be able to lower my demand with my own generation. I fully agree it's fair for poco to pay me less than retail for exports. The only way I could go along with some restriction or penalty against self consumption is if that causes significant demand volatility when they are expecting a "regular" residential demand curve or something (which I am skeptical of).

 

[LarryFine]

I fully agree it's fair for poco to pay me less than retail for exports.

I'm still not sure I agree with that sentiment.

As I said earlier, and while I agree there's a great difference in scale, I would have infrastructure costs, too. From what others have said, my cost per kWh would be higher than that of the POCO, in installation, operation, and maintenance.

I'm apparently a believer in net metering.

 

[electrofelon]

I'm still not sure I agree with that sentiment.

As I said earlier, and while I agree there's a great difference in scale, I would have infrastructure costs, too. From what others have said, my cost per kWh would be higher than that of the POCO, in installation, operation, and maintenance.

I'm apparently a believer in net metering.

Great, so now I have to argue with you that POCO should pay you less and with gunny that POCO should pay you more

 

[LarryFine]

No argument . . . I'm right.

"My kWh are worth more than yours."

 

[electrofelon]

"My kWh are worth more than yours."

That would be a good line to put on a solar company's tee shirts

 

[ggunn]

What is "fair" and what is "advantageous to me" are not the same thing. An honest assessment of what is fair requires looking at a situation from all sides.

I've said all I intend to say and I stand by all of it. The bottom line is that it doesn't really matter what you or I think is fair. All any of us can do is make an informed choice in the environment as it is. It is what it is.

I've related AE's rules and the reasoning behind them (I know the reasoning because I know and speak with these guys quite frequently). In my opinion they have struck a reasonable balance between what is good for higher energy consumers with PV, lower energy consumers with PV, and everybody else, but, again, it is what it is. The POCO sets the rules and our choice is only to play or not to play.

 

[ggunn]

[I said] With solar and wind getting to be bigger players on the grid, management of their effects are getting to be quite challenging. []

It seems to be less challenging than some naysayers predicted in the past.

Have you ever sat and talked with a grid administrator/engineer about the measures they need to take to keep the grid voltage and frequency stable with wind and solar resources jumping on and off the grid? I have, and I can truthfully say that it is a daunting task. I cannot speak to what "some naysayers" have said, though.

 

[winnie]

Have you ever sat and talked with a grid administrator/engineer about the measures they need to take to keep the grid voltage and frequency stable with wind and solar resources jumping on and off the grid? I have, and I can truthfully say that it is a daunting task. I cannot speak to what "some naysayers" have said, though.

For a while various companies would claim to be 100% renewable powered, when what they were really doing was offsetting their _grid_ power consumption with power supplied to the grid.

It was my opinion at the time that this claim was only valid if these companies adjusted their consumption to match the renewable production.

Back to the current discussion, I think that it is fair to relate using solar to offset your consumption to simply turning off a load, but absolutely agree that there are significant differences, so I see the reasoning behind 'buy all, sell all'.

However the needs of keeping the grid stable shouldn't stop with 'buy all, sell all'. Perhaps if you have normal 'consume energy as you wish' combined with 'produce as much as you can', then buy all sell all makes the most sense. On the other hand if you control your loads to match your production (automatically turning off loads as production drops), or if you reduce your production to make it more stable, then buy all sell all makes less sense. Perhaps a combination of properly controlled loads and production would make 'net metering' work for the grid operators.

-Jon

 

[kwired]

For the most part users will use what they will use. Now if clouds roll in and solar production drops off the utility is going to have to rely on other sources to make up for that lost input. Cooling demand on a hot summer day may go down if those clouds roll in, but will be delayed and not instantly reduced.

same with wind production sources and the wind would happen to change in pretty short time.

Whether net metered or not, if actual usage doesn't go down with loss of on site production, demand from utility's other resources will go up. A boiler powered by NG, coal, nuclear... won't suddenly pick up a huge change in the demand if too much energy was coming from those alternate sources at the time and there will be a shortage of power for the demand at least temporarily. If they depended too much on alternate sources there may be a shortage for longer time.

 

[jaggedben]

Have you ever sat and talked with a grid administrator/engineer about the measures they need to take to keep the grid voltage and frequency stable with wind and solar resources jumping on and off the grid? I have, and I can truthfully say that it is a daunting task. I cannot speak to what "some naysayers" have said, though.

I haven't talked to any grid administrators, although I've attended talks by people in related parts of the industry, such as those working on transmission. It may be daunting in some respects, but it hasn't led to any major failures yet. <crosses fingers and knocks on wood>

But what is the point here, exactly? (That remark you quoted was the most in passing of any I made, and I note that you didn't respond to my other points that more directly address the main topic.) If responding to the ups and downs of renewables is a daunting task for grid operators, then it seems all the more true that a flat rate for solar production isn't a good structure for pricing it. It should be better compensated when it's most beneficial.

I keep coming back to storage, even though it's not very viable economically yet, because a) it could be much more viable someday relatively soon, and b) the way it illustrates principles. If I install a solar+storage system and program it to maximize self consumption, that customer's demand can be very flat and nearly nonexistent. It places essentially none of those demands on the grid that you describe as so daunting to grid operators. (In fact that's why it's being incentivised in CA.) If Austin wants to continue to be pro solar and cares about greening the grid, they would not disincentivize storage by charging for the self consumption of such a system. (Not to mention they can't apply their method to DC coupled systems.) For systems without storage, if the issue is highly variable demand, then that can be adequately measured by a single meter in series with the service point.

We both obviously care about the longevity of solar markets for more reasons than just our own jobs. I wonder how much you've thought through the long game here.

 

[ggunn]

I haven't talked to any grid administrators, although I've attended talks by people in related parts of the industry, such as those working on transmission. It may be daunting in some respects, but it hasn't led to any major failures yet. <crosses fingers and knocks on wood>

But what is the point here, exactly? (That remark you quoted was the most in passing of any I made, and I note that you didn't respond to my other points that more directly address the main topic.) If responding to the ups and downs of renewables is a daunting task for grid operators, then it seems all the more true that a flat rate for solar production isn't a good structure for pricing it. It should be better compensated when it's most beneficial.

I keep coming back to storage, even though it's not very viable economically yet, because a) it could be much more viable someday relatively soon, and b) the way it illustrates principles. If I install a solar+storage system and program it to maximize self consumption, that customer's demand can be very flat and nearly nonexistent. It places essentially none of those demands on the grid that you describe as so daunting to grid operators. (In fact that's why it's being incentivised in CA.) If Austin wants to continue to be pro solar and cares about greening the grid, they would not disincentivize storage by charging for the self consumption of such a system. (Not to mention they can't apply their method to DC coupled systems.) For systems without storage, if the issue is highly variable demand, then that can be adequately measured by a single meter in series with the service point.

We both obviously care about the longevity of solar markets for more reasons than just our own jobs. I wonder how much you've thought through the long game here.

I don't know what I can say that I haven't already. Whether AE is "fair" or not in their policies is beyond my control, although I happen to agree with them. Self consumption isn't worth the expense of the batteries if there isn't a TOU tariff structure, and even with net metering it still wouldn't be; in fact, it would be worse. Batteries are a less than zero sum game since none of them have 100% round trip efficiency, and the more the grid pays you for your PV production, the less viable they are for daily use.

Building, maintaining, and stabilizing a grid structure is a very expensive proposition, and every customer on the grid contributes to paying for it. There was (and to some extent there still is) a ground swell of resistance to solar here and elsewhere amongst customers who do not have PV systems who say, with some justification, that under net metering a portion of that expense is being shifted onto them, since a portion of the kWh charge for energy is for grid support expenses. AE is, in addition to a utility, a political body, so they must consider these objections.

 

[ggunn]

We both obviously care about the longevity of solar markets for more reasons than just our own jobs. I wonder how much you've thought through the long game here.

I think about it all the time. In order to survive in the long term the solar industry has got to play nice with all the other players at the table. There is a lot more to it than simply maximizing the ROI for people who invest in it.

You have heard me whine about a particular AHJ hereabouts who will only approve a residential PV system to interconnect in their territory in what amounts to a FIT (feed in tariff) connection. It makes the installation more expensive and more of a PITA to build. What it accomplishes, however, is an end run around the "it's behind my meter and none of your business" argument in favor of net metering. Of course you realize that from an electron's perspective there is no difference between this arrangement and a backfed breaker in a customer's MDP. Ironically, at the moment that AHJ is paying full retail for the kWh's pumped into their grid from PV, so monetarily it's the same as net metering, but of course that will change.

You have also heard me whine about the same AHJ's only rebating systems with very high tilt and oriented west of south. I even branded them as being "anti solar", but I have since amended my position. They have done the research and have determined that systems so oriented help them with their demand curve while other systems do not. They don't require that all systems in their territory be so oriented, but they will only help pay for those that help them. That's their right and you might say their responsibility to their other customers.

 

[ggunn]

You have also heard me whine about the same AHJ's only rebating systems with very high tilt and oriented west of south. I even branded them as being "anti solar", but I have since amended my position. They have done the research and have determined that systems so oriented help them with their demand curve while other systems do not. They don't require that all systems in their territory be so oriented, but they will only help pay for those that help them. That's their right and you might say their responsibility to their other customers.

A clarification: When I first read the AHJ's document about the high tilt and west of south orientation for PV systems in their jurisdiction, I mistakenly thought it was talking about systems for which the AHJ would issue permits, hence my branding them as "anti solar". My bad; they were talking only about systems for which they would pay a rebate.

 

[electrofelon]

I don't know what I can say that I haven't already. Whether AE is "fair" or not in their policies is beyond my control, although I happen to agree with them. Self consumption isn't worth the expense of the batteries if there isn't a TOU tariff structure, and even with net metering it still wouldn't be; in fact, it would be worse. Batteries are a less than zero sum game since none of them have 100% round trip efficiency, and the more the grid pays you for your PV production, the less viable they are for daily use.

Building, maintaining, and stabilizing a grid structure is a very expensive proposition, and every customer on the grid contributes to paying for it. There was (and to some extent there still is) a ground swell of resistance to solar here and elsewhere amongst customers who do not have PV systems who say, with some justification, that under net metering a portion of that expense is being shifted onto them, since a portion of the kWh charge for energy is for grid support expenses. AE is, in addition to a utility, a political body, so they must consider these objections.

Just want to be sure you are understanding my position. You seem to keep not commenting specifically on it and keep talking about terms like "batteries" and " net metering". Having one meter doesn't have to be net metering. Basically one meter just allows you to directly consume what you make. Exports to the grid could still be a different rate than imports. I don't believe it's "their grid" inside my house