Building Reserve and Using KWH

[bcroe]

We are seeing -7 F. The 6 Heat Pumps installed 2018-2020 are
all doing their jobs, which is usually heating buildings. They can
AC, but very little of that is required here. 5 are in the house, like
one in each corner and 1 in the area of the basement with an
outdoor wall. Starting with 3 HPs temps were a little uneven and
a fan helped one room. Now with more units and the house
blower circulating the air every hour, things are pretty good.

Some would say I have way too much HP capacity. But if one were
to fail, the others could just work a little harder, no crisis like a
furnace failure. What they call RIGHT SIZING I call JUST BARELY
ENOUGH FOR MOST SITUATIONS. And the minimum HP capacity
would be backed up by a resistive heat system with a COP of 1.
With my capacity the HPs can cover that too, automatically,
even if their COP drops pretty low for well below zero F. The
COP will pick up immediately as temps rise a bit. The factor
driving the above is initial cost. But mini splits are easily DIY,
bringing costs to less than half.

2023/4 saw some tree growth dropping sap on on one
panel string, which only gets removed with a scraper
(razor blade). The tree got cut back summer 2024, but
unfortunately a 250W panel was damaged by a falling
branch. It was replaced (in the dead of night) with my last
spare, better find some more.

The solar plant has been doing very well, with absolutely
minimum maintenance. I clear the snow off part of the array
about 4 times a year, the rest pretty much clear themselves.

In the switch over to straight electric water heating, I have
done some manual control of the previous propane unit. I am
suspecting after 13 years of our hard water, the high efficiency
is not so high. At my previous house with similar water heater,
it did not seem to run sooo long. And that unit could be
unplugged for several days before I ran out of hot water, this
one completely cools off in a day even with the circulator
turned off. PERHAPS mineral buildup on the heat exchanger is
interfering? This problem would go away with the electric heater,
the heat cannot go up a vent not present, it will find its way to
the water. If that strain eventually burns out the resistive
element, it is easily replaced. With 2 elements I would still have
service.

Bruce Roe

[solar pete]

Hi Bruce,

I always enjoy reading your reports, thanks for sharing mate, cheers

[bcroe]

In my 12th year of HVAC and electric being solar powered, things
are not too exciting. The same pair of 7.5KW Fronious inverters
providing Net Metering, remain in service. Another identical pair
remain as backup, one is mounted and could be switched into
service by reconnecting a pair of wires.

With regular attention to energy efficiency, the use of Heat Pumps
year around has left enough surplus energy to do several luxury
things. The backup propane furnace remains out of service, but
the (recently replaced) air circulation blower is run for a fraction of
every hour. This allows a large electronic air filter to minimize dust
in the air. Use of a central vacuum with outside exhaust does the
same. And I run a dehumidifier.

One of my goals is to avoid failures resulting in a crises situation,
such as the furnace quiting in winter. The HPs around the house
have done this very well, and the air circulation evens out temps
if one is not running. I am now testing to see what kind of lifetime
they will provide. The installed capacity would be considered excess
by some, but serves my goals. First, I can make it through the very
coldest nights without inefficient electric resistance auxillary heat
(though that was initially used and is in standby). Loss of an HPs
capacity can be covered by the others, till a convenient service time.
And I expect that not working too hard, HP life will be extended. I
believe the efficiency is not affected much by greater capacity.

Realize the $ cost of a DIY mini split is less than half the cost of
hiring the job. A replacement with all the support parts in place,
would be even less $ or time.

After quite a few years waiting for a Nyle Geyser water heater HP
attachment to be available, I give up and am going another way.
The cost of my propane water heating keeps rising, meanwhile I
gave the PoCo some 5000 kWh of energy at April true up. I am
tired of water heaters that rust through in a few years. And my
propane burner recently quit, the flame detector failed to keep it
lit. I cleaned it for now, actually have a backup on the shelf, but
better to use my surplus kWh and stop buying any propane.

So I bought a Stainless Steel tank, lifetime tank electric Water Heater.
It might actually require more than my kWh surplus, better that than
giving kWh away and buying propane. Once it is in service, I will
again be investigating ways to couple in an HP. I doubt the HP WHs
come in SS, and I do not trust them long term.

The WH could be regarded as a small energy storage unit, something
my Net Metering arrangement does not have. So other ways of
increasing efficiency might be possible. Remember my array
inverters run in clipping up to 8 hours on sunny days. Pulling some
water heating DC direct from the array could pull the inverters out of
clipping, getting an increased total energy for that time. If that worked,
could even throw up a few more south facing panels just for helping
heat water.

Working near the inverters a couple days ago, it was a pleasure to
note how well they performed under lighter clouding. Inverters would
run at near full power, to near half if the clouds got more severe. This
all day long, turned in 100 kWh for the day. My day record for the
15 kW plant is 157 kWh. I must point out this is possible with panels
becoming so cheap, catching maximum sun at all hours. Trackers
were used to try and do this when panels were far more expensive,
but a tracker cannot compensate this way for clouds.

Bruce Roe

[DanS26]

Here is what the Nyle rep says........

"It is (disappointing), feel free to let your congressmen know that you would like the DOE to qualify heat pumps, sold without storage, to qualify for energy star. If the DOE makes this change we would work on releasing a residential heat pump again."

[DanS26]

Hey Bruce,

Just got word from a Nyle representative that the current DOE regulations will preclude them from releasing a residential heat pump water heater addon device for the foreseeable future. This is very disappointing since they were in development of replacement unit for the Geyser RO.

Not sure why or what is causing the problems with the DOE regulations.

I installed the Geyser RO in 2012 and run it only in the daytime during solar production. I replaced a relay switch about 5 years ago and bypassed a faulty high pressure safety switch last year. I use a current transformer to monitor the compressor amp draw to now monitor safe operation in lew of the safety switch. Not recommended unless you like to monitor things. It just keeps chugging along and produces all the hot water I need for pennies a day. I asked Nyle if they would provide a supply of off the shelf spare parts since they apparently will not be needing them in the future. Somewhat complicated to work on since it is a closed system that most DIY'ers would not tackle.

[Rade]

I am not a lawyer but RI law is available on line. Some great night time reading for Rhode Island Net Metering:

R.I. Gen. Laws § 39-26.4-3

My reading of it: 12 month annual true up recommended, but not required. It is up to the specific utility to define the exact plan. Blah, blah, blah, if you have too many credits they won't pay/credit you more than 25% over your actual annual usage.

One interesting line give the utility a way to change the plan with enough cause.

"Should there be a material change in circumstances at the eligible net-metering system site or associated accounts during the twelve-month (12) period, the estimates and credits may be adjusted by the electric distribution company during the reconciliation period."

This is pretty dense reading and really should be interpreted by the net metering liaison for your POCO.

I find it hard to believe a POCO can't give a customer the hard facts on how they will or won't be billed since somebody has to write the program to generate the bills. How do you write a program without having a spec?

Just my 2cents.

Thanks for the information! Did not think to look at the RI statutes. I will look further into it. Rade

[J.P.M.]

Dave: Add my $0.02: Seems to me that POCO policies aren't written to be understandable by POCO customers - just the opposite - they're written in such a way so as to keep the POCO out of a lawsuit as well as be a roadblock to understanding.

Further, it also seems to me that any POCO's rules as they apply to net metering in particular are always written so as to be as difficult to understand as possible and also usually so that they favor the POCO in cases where interpretation is necessary.

Don't forget that PV and other distributed generation methods are a real PITA for POCOs.
Pardon the rhetorical question but If so, what incentive do they (the POCOs) have to be one iota more cooperative to PV system owners than they are required to be by law ? No surprises there.

[oregon_phil]

I am not a lawyer but RI law is available on line. Some great night time reading for Rhode Island Net Metering:

R.I. Gen. Laws § 39-26.4-3

My reading of it: 12 month annual true up recommended, but not required. It is up to the specific utility to define the exact plan. Blah, blah, blah, if you have too many credits they won't pay/credit you more than 25% over your actual annual usage.

One interesting line give the utility a way to change the plan with enough cause.

"Should there be a material change in circumstances at the eligible net-metering system site or associated accounts during the twelve-month (12) period, the estimates and credits may be adjusted by the electric distribution company during the reconciliation period."

This is pretty dense reading and really should be interpreted by the net metering liaison for your POCO.

I find it hard to believe a POCO can't give a customer the hard facts on how they will or won't be billed since somebody has to write the program to generate the bills. How do you write a program without having a spec?

Just my 2cents.

[Rade]

azdave - I wholly agree! I am very interested to see what our May and June statements offer.

Other than what my interconnect agreement states ("...credits accrue until used"), I cannot get any more information. One thing about my solar architecture is that it was modeled on the worst month of electrical usage we had. We came online on May 10 2023 and June showed the first net credits. I suspect that the system will generate and bank enough power to deplete the credits by next April when we start to generate more than we are using.

[azdave]

My agreement only states that the credits will continue to accrue, and be used to offset grid usage when not producing sufficient energy. As I mentioned, we blew through last seasons credits by February and I've had three electric bills, though the last one was only $36.

I've heard there are some grid-tie contracts where the banked energy just continues to accumulate year after year. That would be better, in my opinion, as I would rather have the full value to use later as opposed to receiving a wholesale buyout annually.

[Rade]

Don't you have a copy of the interconnect contract you signed? No one here will known that answer since we can't see what your agreement says. There is no "standard" grid-tie agreement that all POCO's use and many newer agreements are far less beneficial to the consumer.

My agreement only states that the credits will continue to accrue, and be used to offset grid usage when not producing sufficient energy. As I mentioned, we blew through last seasons credits by February and I've had three electric bills, though the last one was only $36.

[azdave]

And that brings me back to my question - Our anniversary is on May 10. I'm wondering if any credits I am (finally) generating will be zeroed out at that time? No one in any know seems to be able to answer that; our PoCo website only states that my credits will continue to accrue and then be used towards standard billing once we have to begin pulling from the grid. I guess I will find out on May 12 when the next statement comes in. We churned through our credits by February.

Don't you have a copy of the interconnect contract you signed? No one here will known that answer since we can't see what your agreement says. There is no "standard" grid-tie agreement that all POCO's use and many newer agreements are far less beneficial to the consumer.

I'm in the desert southwest so winter is when I build up reserve. My anniversary date is the end of April and the usual 2500-3000kWh excess I have banked around then is either paid out as cash or appears as a credit on my statement. I am not allowed to build up an unlimited amount of reserve kWh year after year but at least I get the wholesale value for it once per year. In the initial contract years, there was very little reserve to pay out but with the kids moving out and other lifestyle changes, I now receive enough credit in April to cover my monthly fixed connection fees for the next 12 months so I haven't sent a single payment to my POCO in almost 3 years. I reached ROI at just over 6 years and still have 11 years on that contract.

[bcroe]

Those are very good numbers! So my question is; you
said you gifted 5,600kW back to the PoCo. Did the PoCo wipe your credits to
zero on your interconnect anniversary? Rade

I started out pretty obsessive about energy consumption
when I moved here in 2004. I tracked down every load on
some 60 circuits, and was eventually able to eliminate some
240W of Vampire loads, coming to some 2100 kWh a year.
Many of these loads were outside the house (garage door
opener, attic fan, etc), so they did not even contribute at an
inefficient level to heating the house. Many were reduced
from 4 or 15W, to well under 1W. All this was done before
going solar in 2013. In 2018 use of mini split heat pumps
allowed adding in without energy purchases, some items
previously not allowed, including frequent air circulation
thru my electronic air filter, a summer time dehumidifier,
and continuously warming a shop building.

I did not give the PoCo back 5600 kW, the most power I can
generate is 15kW. I did accumulate an energy surplus of
5600 kWHOURs by the (April 2) reset day, which means
starting the next Net Metering year at zero under my plan.
Surplus is a gift to the PoCo, not to worry as it cost me
nothing extra to generate. This is a zero carbon footprint,
zero energy purchase operation, not a for profit. Bruce Roe

[Mike 134]

Northern Illinois ComEd is the power company for me. If i have a surplus on my April bill it just goes POOF!!! Not even a thank you for the free KWHs from the power company. Then the "new year" starts again building credits (I hope).

[Rade]

Those are very good numbers! So my question is; you said you gifted 5,600kW back to the PoCo. Did the PoCo wipe your credits to zero on your interconnect anniversary?

I'm coming up on my 1st anniversary on May 10; I'm kinda hesitant to celebrate for the moment. As I often complain, our house is a bit of a power hog and right now, I am at a 1,220kW deficit if we are going to break even next winter. But the weather is warming, the electric furnace has been turned off and our power meter is finally, consistently clicking downward (more power back to the grid than the house is using). >If< the weather continues to cooperate, we may make up that deficit by our anniversary. In May of last year, we generated 1,900kW of power (peak for the year).

And that brings me back to my question - Our anniversary is on May 10. I'm wondering if any credits I am (finally) generating will be zeroed out at that time? No one in any know seems to be able to answer that; our PoCo website only states that my credits will continue to accrue and then be used towards standard billing once we have to begin pulling from the grid. I guess I will find out on May 12 when the next statement comes in. We churned through our credits by February.

I think it was you who advised to just be patient; thank you! Yes, all in all, during the first 4 or so months, we had about a month total of new system configuration bugs that knocked our generation down during peak sun season. The bugs seem to have been worked out and our solar architecture has been running rather well for many months now. Looking forward to... not being so damn obsessive about power consumption.



Rade