Zero export system without interconnection agreement

[ggunn]

IMHO fair charging would have something like a 'meter charge' (flat rate just to have service), a 'capacity charge' (a charge for power that the utility guarantees will be available for your use, even if you don't use it), a consumption charge (a charge for each kWh that goes through the meter toward the consumer, possibly time of day variable) and a production credit (a payment for each kWh that goes through the meter toward the utility, possibly time of day variable and different than the consumption charge).

Any energy that I produce and use immediately should be charged exactly the same as if I simply decided not to use the energy; if it doesn't result in a net flow through the meter it simply should not count, just like the various 'one way' systems that I described.

Just my opinion of what is 'fair' from the point of view as an educated consumer.

OK, but Austin Energy and a few other AHJs I know of do not agree, and if you want to play in their sandbox you play by their rules. FWIW, AE tells us contractors that there are many other AHJs evaluating the way AE regulates residential PV systems.

 

[ggunn]

Sure you could do that (where for "billed" I would use the word "credited"), but I think the argument is that the behind the meter consumed kWh generated by someone in a high tier would still be worth more than the behind the meter consumed kWh by someone in a low tier. So if that's undesirable for whatever economic or social policy reason, you have to separately meter all solar. Clearly such a policy is intentionally treating a kWh avoided differently from a kWh generated.

Precisely. Politics does enter into it since the Austin City Council is also the Austin Energy Board of Directors. Before the institution of the Value Of Solar policies lower income persons were frequently complaining at city council meetings that PV systems were "rich man's toys" and objecting to PV system rebates.

 

[ggunn]

Incidentally, another AHJ nearby has countered the argument jaggedben has by making all PV systems in their jurisdiction essentially FIT (feed in tariff) systems. They all have to be connected outside the customers' meters as separate services with meters of their own.

 

[jaggedben]

Yes, and it goes beyond just how much they are going to pay a customer for energy they put in, they need to be able to determine how much energy to expect and use that information to determine how much capacity their conventional generation needs to be prepared to deliver without having any disruptions to some or even all parts of the system.

Does having large amounts of DG on a grid really make load forecasting that much more difficult? Seems like it's just another factor to consider, which no doubt makes it more complicated, but it doesn't seem to be by much. There are grids around the world with massive amounts of solar DG and I've seen no evidence that it's taking grid operators by surprise every day.

Now what probably would make it more difficult is not knowing how much DG you have connected to your grid. Which is why, given that the non-export systems under discussion can in many cases compete cents-to-cents with import rates, maybe utilities and regulators shouldn't push forward policies that financially penalize above-board applications for interconnection of residential scale systems. The technology is there and the world has changed like it or not.

 

[jaggedben]

Incidentally, another AHJ nearby has countered the argument jaggedben has by making all PV systems in their jurisdiction essentially FIT (feed in tariff) systems. They all have to be connected outside the customers' meters as separate services with meters of their own.

That doesn't counter my argument that such policies stifle innovation and fair competition.

 

[ggunn]

That doesn't counter my argument that such policies stifle innovation and fair competition.

I don't see where any of those buzzwords are supported by your argument, but anyway, what it does is license every PV system owner to be a supplier to the grid just like any other generator. The utility makes a deal to buy the energy and then they sell the kW-hours thus generated along with the energy they get from all other sources to everyone connected to the grid.

A prospective system owner does a cost-benefit analysis and decides whether it is worth it to them to become an energy supplier to the grid. The PV system connection to the grid is outside their meter, and where the PV system is physically located is irrelevant; it could theoretically be on another piece of property that has no consumption meter at all. As I said, it's essentially a FIT, and consumption isn't in the equation.

Oh, and something I forgot to mention is that they offer a rebate in addition to the FIT deal, but it's only for systems oriented between due south and due west because PV systems that generate power in the afternoons give them the help that they need.

 

[jaggedben]

Right, so for example if a customer wants to install a solar system with battery backup for grid outages, and get a some compensation for exporting to the grid when they have excess, that combination is not allowed, for no very good reason. That's what I'm getting at with thise buzzwords.

 

[GeorgeB]

From what I understand, Duke doesn’t pay for excess, we do.

For roof area reasons, I only expected my 4.25kW DC to offset 35% to (if I bought a new high efficiency air conditioner) maybe 60%. It is slightly possible for me to source more than I sink in winter; we cook, heat the house, and heat water with gas. Duke's policies seem to change regularly; I have the rate schedule from when I started which I think is grandfathered for some number of years.

It was more a political statement to tell our kids we care about the environment than an economic decision. I guesstimated payback at 7-9 years. My wife seems to like paying realtors every 8 or 9 years so it was a wash. When we bought this house, she said "this is our last house" as she said about the prior one. She now is thinking about a retirement community for our just over 70 bodies. Ah well, I won't lose much if any. I __HATE__ moving.

 

[kwired]

For roof area reasons, I only expected my 4.25kW DC to offset 35% to (if I bought a new high efficiency air conditioner) maybe 60%. It is slightly possible for me to source more than I sink in winter; we cook, heat the house, and heat water with gas. Duke's policies seem to change regularly; I have the rate schedule from when I started which I think is grandfathered for some number of years.

It was more a political statement to tell our kids we care about the environment than an economic decision. I guesstimated payback at 7-9 years. My wife seems to like paying realtors every 8 or 9 years so it was a wash. When we bought this house, she said "this is our last house" as she said about the prior one. She now is thinking about a retirement community for our just over 70 bodies. Ah well, I won't lose much if any. I __HATE__ moving.

and at the end of those 7-9 years how many components will be near due for replacement?

 

[gadfly56]

Right, so for example if a customer wants to install a solar system with battery backup for grid outages, and get a some compensation for exporting to the grid when they have excess, that combination is not allowed, for no very good reason. That's what I'm getting at with thise buzzwords.

I don't believe that's what's being said at all. Just that if you are grid-tied, you have to clear it with the POCO.

One thing not discussed regarding "virtual zero export", is does this equipment have a failure mode which could lead to unregulated dispatch of PV power to the grid?

 

[ggunn]

Right, so for example if a customer wants to install a solar system with battery backup for grid outages, and get a some compensation for exporting to the grid when they have excess, that combination is not allowed, for no very good reason. That's what I'm getting at with thise buzzwords.

I don't see any stifling of innovation or fair competition; I just see that you don't like it. BTW, in that other jurisdiction all PV generated energy is "excess" and compensated for by the utility. As under the AE rules, generation and consumption are accounted for separately.

A customer in that other jurisdiction can install battery backup as well as solar; they just have to be separate systems. The PV system would be on its own service as I described while the battery back up would be on a transfer switch behind the consumption meter. The only wrinkle in that scenario is that the PV system cannot contribute to the backup, but if you run the numbers you will find that the capacity of the PV to run during an outage normally contributes very little to a customer's bottom line.

All that said, I reiterate that I make no judgement of right or wrong on these policies; I am just stating the way things are and the reasoning behind it. Obviously, these utilities disagree with you on whether their reasons are valid. They do not see having to pay full retail for energy from owners of private PV systems who do not have to shoulder the expenses of maintaining grid infrastructure as "fair competition".

 

[jaggedben]

and at the end of those 7-9 years how many components will be near due for replacement?

Probably none.

 

[jaggedben]

I don't believe that's what's being said at all. Just that if you are grid-tied, you have to clear it with the POCO.

I don't think you followed the details. How do I install solar with battery backup for loads if I'm not allowed to connect solar to a meter with loads?

One thing not discussed regarding "virtual zero export", is does this equipment have a failure mode which could lead to unregulated dispatch of PV power to the grid?

Define 'unregulated.' (e.g. for how long) The general answer is not likely, although details depend on the particular product. Some are more dependent on comms. In some cases an initial installation error (getting the CTs backwards) might be a problem, but once fixed it wouldn't fail that way due to getting old.

 

[jaggedben]

...

A customer in that other jurisdiction can install battery backup as well as solar; they just have to be separate systems. The PV system would be on its own service as I described while the battery back up would be on a transfer switch behind the consumption meter. The only wrinkle in that scenario is that the PV system cannot contribute to the backup, but if you run the numbers you will find that the capacity of the PV to run during an outage normally contributes very little to a customer's bottom line.
...

That's just not true. I run those numbers everyday.

 

[electrofelon]

They do not see having to pay full retail for energy from owners of private PV systems who do not have to shoulder the expenses of maintaining grid infrastructure as "fair competition".

And I have no problem with that and actually agree. What I have an issue with is the inability to "use before meter".

 

[tortuga]

Here's an idea, install a system without telling the POCO, tell them, and see what happens. Please report back how it goes.

So A few years back when these plug and play systems came out I ordered one, a 600W inverter, and connected it up to some old panels to see what happened.
I got a kick of showing it to my engineer friend that works at the local POCO.
He looked at it plugged in, shrugged and was like 'we know about these and will never do anything'.

 

[ggunn]

That's just not true. I run those numbers everyday.

Under what assumptions? If a grid outage lasts one hour, how much energy would a reasonably sized PV system produce during that time, even considering a net metering scenario where the system owner receives full retail credit for it? What would be the value of that energy, even if the outage were in the most productive part of the day? Pennies.

 

[ggunn]

And I have no problem with that and actually agree. What I have an issue with is the inability to "use before meter".

But when you do that you are participating in the market and selling your PV production at the market rate. The fact that you are in effect selling it to yourself is not relevant. The utilities contend that the entire grid is under their jurisdiction, even the part of it that is on the customer's side of the meter, and if you are feeding it you must do so according to their rules.

Once again, I am not commenting on rightness or wrongness; it's just the way things are.

 

[electrofelon]

But when you do that you are participating in the market and selling your PV production at the market rate. The fact that you are in effect selling it to yourself is not relevant.

I just cannot agree with that.

 

[wwhitney]

So for AE, I think I object to the idea that during an outage, you can't use your PV to charge your ESS. That would be a resiliency fail for an extended outage. Do they allow a configuration that would enable that? E.g. a consumption meter behind the MID, in lieu of a PV meter? Since consumption = net grid + PV, it's enough to meter any 2 of those.

Cheers, Wayne