Solar production. Panel ratings/claim vs reality

[paulsharvey]

In truth, this is kinda a strong side of eventual solar power de-centralization. You could eliminate the need to run the expensive infrastructure out to reach a dozen homes miles from anything else. Suburban and urban areas, it's probably not the future. I still think it's a mix of all sources that is needed. Nothing wrong with a remote location having solar on every home, but also propane generators for surge needs, or diesel. People don't want to hear it, but a power company (or internet or gas) is probably loosing money on every rural customer. If you look at the number of poles to reach a home (or underground feet, but that's far more $$$), if you have more than maybe 4 poles per rate paying customer, they are all probably costing the utility money, unless it's a high usage, commercial customer.

 

[paulsharvey]

It's funny, transportation, telecoms, power, Amazon, and USPS, all refer to the problem as the "last mile". Probably 95% of customers or more are within easy access to good infrastructure within a mile; but getting from that aertierial to Every home, is the challenge.

 

[LD1]

7.5¢/kWh for "excessive" generated power is excellent. Go ahead and overbuild your system.

Around here we get 2.5¢/kWh for any power we put on the grid, limited to the amount we draw from the grid at 11.5¢/kWh. Is better to get 2.5¢ than to throw it away.

Meanwhile my PV system will have batteries because it isn't worth giving the power to TVA.

The problem with a blanket "go ahead and overproduce" is that you have to run calculations and see if it is worth it.

When sizing a system.....it can be simplified down to a total system cost per watt.

Currently I pay ~12.5 cents per kwh. So any and all production up until that point....I am directly saving (putting in my pocket basically) 12.5 cents for every kwh I produce.

If I produce more than I use.....now I am saving (putting in my pocket)about 40% less per kwh. So that pushes out the ROI by oversizing. So some number crunching needs done.

Make sure you are adding generation and transmission for your overall cost.

Also be weary of that, they'll buy back, but I've heard of companies starting to charge transmission on the buyback. Since you're using their lines.

My coop dont charge a distribution for the power they buy back. I will directly get credited 7.5 cents per kwh.

If they don't buy back or I use everything produced, totally OK with that. Our local co op has been great over the years. Not many grid down days and they have always fixed things real quick.

Now looking into methods of ground mounting panels with angle adjustment for different times of year. The prebuilt mounting system/ kits seem to get pricey quickly. Not into roof mounting with the amount of snow we can get in some winters. Seems being able to set panels almost vertical on a ground mount would also help with sluffing the snow off versus a low angle roof trying to pull it off with a roof rake, and work well with snow reflection feeding the backside of the Bifacials.

Just thinking out loud, reading this thread with interest.

Yes, coop's are good in that we rarely have outages....and when we do they are short-lived.

IF you are liking an adjustable ground mount...I would look no further than Sinclair sky-rack Sinclair Designs & Engineering - Michigan's leading Solar Racking Manufacture

The latest thing is the bifacial PV panel which is partially sensitive on the backside. Can sometimes make power from that which is reflected from the ground.

Have been some interesting experiments in mounting these panels vertical. Good yield early and late in the day. Area under the curve of production is similar but not quite as good as "optimal angle" mounting. Depends on your latitude.

I saw those experiments too of vertical mounting. Yes total production is less.....but a combo of vertical and horizontal can really flatten a curve and have good production ALL day. But from what I saw the single biggest benefit of vertical was still allowing use of the land between the panels for farming crops that dont get tall. Like hay being the biggest one

Probably worse than that. The Federal Grid Tie law says the utility only has to pay the Audited Incremental Cost of Generation. They don't have to pay more than it would cost to produce a kWh themselves. For TVA that is about 2.5¢/kWh. Most TVA associated utilities charge around 10¢/kWh for the power delivered to one's home. The difference is the cost of that distribution grid.

Long ago I wise experienced engineer told me, "The biggest cost in running an electric power utility is the cost of money." In other words, "interest".

The federal regulations dont apply to a non-profit coop. They are not bound by any net metering regulations or public utility stuff.

But also, the rural coop's dont actually generate power themselves. They have to directly buy it off someone. In my case here in ohio....they purchase the electric from buckeye power.....and buckeye power sets the rate in which they will credit my coop for people overproducing on solar. That rate is simply passed on to me.

 

[LD1]

OP here

I dont know where I left off in this thread without going back and re-reading. But after about 2 months of getting information from my rural coop.....which was like trying to herd cats....I am moving forward with a solar install.

The details of my net-metering......

Currently a non-solar customer's bill is structured 3-part
1. service availability charge....$50. Everyone pays this just for the pleasure of being tied to the grid.
2. Generation and transmission....8.6 cents/kwh. This is what my coop has to pay buckeye power to deliver electric to local sub-stations
3. Distribution.....2.6 cents per kwh. This is what pays my coop to maintain their local distribution network from substations to residences

Those last two are always fluctuation a little. But this last bill totaled ~11.2 centes per kwh.

There is also a kva surcharge of $2.15 per kva of allocated transformer size over 10. Literally no one without solar sees this charge. Because a single residence with a 15kva xfmr.....that charge would be $10.75. Meaning if you didnt use at least $10.75 worth of electric....you get charged as if you did. and at ~11.2cents/kwh....that would be less than 100kwh.

Now for solar.....things change. The generation and transmission rates stay the same. But the new service availability charge becomes $57. And the $2.15 per kva over 10 absolutely may come into play.

Now in my case...I have two meters. One at my shop and one at my house. So I am paying The $50 x 2. At the time I built my shop....I was looking at a ~400' run of 350mcm wire to feed the shop, and having just bought the place and possible future plans of a new house on the hillside right where I would have to trench this wire.....and the ~$2500 it would have cost me....I opted for a new service.

Now that things have changed I want to tie the shop and house together and get rid of that $50/mo charge just to have two accounts.

I was originally going to tie the shop and solar to my house meter....but property layout, wire sizing, etc, it makes more sense to tie my house to the shop meter. So that is what I am planning.

 

[LD1]

Continued.....didnt want a single long post....

So far I have everything ordered and expect panel delivery today.

Details of the system....
30 canadian solar Bifacial 540w panels
7 Hoymiles 4-into-1 inverters
1 Hoymiles 2-into-1 inverter
Those trunk lines will feed into a 100a outdoor main lug load center. Each trunk line can handle 3 inverters. So I'll have 3 trunk-lines coming in to 30a beakers.

The main lugs of that panel will feed a 100a disconnect as required by my coop. That disconnect and main panel will be at the array. Then a ~125' trench to the meter and connected to the grid.

All of that is gonna sit atop a sinclair skyrack with season adjust jacks.

The only thing I have not purchased yet is MC4 extender cables. Given their cost....there are too many variables that may change how many or how long I need. Given that I dont know how long the leads are on the inverters, or how/where I am mounting them, or the orientation of the panels if some, or none of the panel leads will reach....I have opted to wait until I have the array built, and inverters mounted to see the exact quantity and lengths I need.

The panels were ~$4500 delivered. The inverters and trunk cabling was ~$3600 delivered. The skyrack was ~$4600 delivered. And I have other local expenses for URD wire, panels, and boxes.

Current expense to date is $15,300

I will still have ~$500 for MC4 cables, ~$600 for concrete for the posts, and ~$600 for a truck load of limestone for under the panels. (brightest color stone I can think of that may maximize bifacial gain). And once I get limestone coated under....I may look into some of that bright white quartz decorative rock. Probably a waste given limited gains but will look good.

So all in I am expecting about $17k

However, about $1300 of that cost really has nothing to do with solar as it is simply connecting my house and shop to a single service.

Given the 30% fed credit.....I am thinking true system cost to be $10k-$11k.

And with this size, I think I will overproduce quite a bit in summer. At least according to PVwatts calculator. And still be quite short in the winter.

But ballparking the ~11.2c savings and the 7.8 cent for overproduction....I am anticipating ~$2000 yearly savings.

So 5-6 year ROI expected for the solar.

Orders were just placed within the past week or two. Nothing onsite yet but I will take pics and detail the build and start a new thread once I am up and running.

 

[Grumpycat]

The federal regulations dont apply to a non-profit coop. They are not bound by any net metering regulations or public utility stuff.

But also, the rural coop's dont actually generate power themselves. They have to directly buy it off someone. In my case here in ohio....they purchase the electric from buckeye power.....and buckeye power sets the rate in which they will credit my coop for people overproducing on solar. That rate is simply passed on to me.

You missed the meaning of "only have to pay the Audited Incremental Cost of Generation". The utility is free to pay more if they wish.

Utilities such as Alabama Power have circumvented any good intentions of the grid tie law by implementing connection fees based on PV array capacity. These fees can exceed the credits received for production during the winter. A couple of years ago there were less than 200 PV solar systems connected to Alabama Power.

 

[LD1]

You missed the meaning of "only have to pay the Audited Incremental Cost of Generation". The utility is free to pay more if they wish.

Utilities such as Alabama Power have circumvented any good intentions of the grid tie law by implementing connection fees based on PV array capacity. These fees can exceed the credits received for production during the winter. A couple of years ago there were less than 200 PV solar systems connected to Alabama Power.

No, the rural coop's of this country that arent bound by public utilities and invester owned companies do NOT have to offer net metering.

Varies by states of course...

But the answer is my rural coop "only has to pay" absolutely nothing at all if they dont want to.

 

[Jstpssng]

We're learning about solar subsidies here.
The utilities are required to pay .20, but only allowed to charge .05.

 

[davrow]

No, the rural coop's of this country that aren't bound by public utilities and investor owned companies do NOT have to offer net metering.
Varies by states of course...
But the answer is my rural coop "only has to pay" absolutely nothing at all if they don't want to.

Generally really like my coop, but they are anti solar. No net metering, no buyback. And limited to 5kw max grid tied solar allowed.
I want (need?) 12kw of solar. Can't have it.

 

[ponytug]

Generally really like my coop, but they are anti solar. No net metering, no buyback. And limited to 5kw max grid tied solar allowed.
I want (need?) 12kw of solar. Can't have it.

Have you looked into solar systems with export limits? Some California utilities are ok with larger solar systems if the maximum export is capped.

All the best, Peter

 

[davrow]

Have you looked into solar systems with export limits? Some California utilities are ok with larger solar systems if the maximum export is capped.
All the best, Peter

Actually, I'm thinking I will just feed a new panel with what I want solar (with batteries) powered and leave the main panel for the grid stuff. I see no reason to involve the utility company at all with this approach. Fewer hoops to jump through. Thanks for the suggestion.

 

[jyoutz]

In truth, this is kinda a strong side of eventual solar power de-centralization. You could eliminate the need to run the expensive infrastructure out to reach a dozen homes miles from anything else. Suburban and urban areas, it's probably not the future. I still think it's a mix of all sources that is needed. Nothing wrong with a remote location having solar on every home, but also propane generators for surge needs, or diesel. People don't want to hear it, but a power company (or internet or gas) is probably loosing money on every rural customer. If you look at the number of poles to reach a home (or underground feet, but that's far more $$$), if you have more than maybe 4 poles per rate paying customer, they are all probably costing the utility money, unless it's a high usage, commercial customer.

That’s why most rural areas are served by non profit rural electric cooperatives.

 

[paulsharvey]

With out going to far down a rabbit hole; was speaking with an engineer for a large power company about a problem, work involved. He has a single customer, dead end line, feeding an abandoned house, that he has to spend something like $160k to replace the feed too. That's not anything he can pass on to them, they have to eat the cost to maintain the connection. He half jokingly brought up, we could have bought and installed them a solar system for way less. Not an actual option of coarse, it has an existing connection that must be continued by the utility.

To make it worse, it's his end point, the co-op picks up further south, so it's strictly a single abandoned home.

 

[ericm979]

I can't find the article now but I read somewhere that utilities are installing solar+battery mini power plants to serve small groups of far flung rural homes where maintaining a line is expensive. It might not be in the US, we tend to lag on some of these things.

 

[Grumpycat]

I can't find the article now but I read somewhere that utilities are installing solar+battery mini power plants to serve small groups of far flung rural homes where maintaining a line is expensive. It might not be in the US, we tend to lag on some of these things.

Article from 2019:

https://www.tesla.com/blog/introducing-megapack-utility-scale-energy-storage

 

[paulsharvey]

So, don't know if anyone ever noticed; but you know who really pushed the early cell phones, and was leaps ahead od the US? Ericcson and Nokia, Swedish and Finnish companies. Apparently, they were very early adopters of cell phones, because they are both Very large countries, each with a couple denser areas, and scattered very low density areas. They were able to run a fiber (or copper in the earlier era) out to cell towers, and then feed something like a 25 mile radius out from the tower.

Point being; I could see micro solar package plants, being a very good option in India, much of Africa, Egypt, the northern 'Stan's, ect. Where the base infrastructure is limited. If we say a package solar plant could be shipped in 4 containers, (easily slung off a Mi-26 were roads are limited), and power up a hundred village center, for a reasonable rate. I'm not talking about 5000 acre solar farms; I'm talking about lights in maybe 8 commercial-gov buildings, a well pump, and water treatment, and maybe 20 amps worth to the closest residences.

Some super dirty, fast numbers, you could provide something like a very limited supply. to roughly 160 homes per acre of panels. Note; I'm not talking US homes, I'm talking about a light bulb or two, some USB charging, and a fan.

 

[ponytug]

I can't find the article now but I read somewhere that utilities are installing solar+battery mini power plants to serve small groups of far flung rural homes where maintaining a line is expensive. It might not be in the US, we tend to lag on some of these things.

I don't know of any in the US, either.

A relative is doing that overseas. His company specializes in alternative energy supplies. For places like say islands, solar, plus battery, plus a generator makes for a robust power subsystem, typically with a much lower cost per kWh, due to the high supply costs of diesel to remote places.

In the US, the Rural Electrification Act got power to most remote places, but there are always folks building off grid installations, especially when the hook up costs by the utility is exorbitant, like that certain executive in the Bay Area, whose utility wanted an insane amount of money ($270k) to run the power a few hundred feet to his place. He put in solar and a large battery (not a MegaPack, next size down) for less.

US armed forces use solar plus batteries as well for certain sites. Forward costs of diesel can be hundreds of dollars per gallon, and silence also has its value.

All the best,

Peter

 

[ultrarunner]

So, don't know if anyone ever noticed; but you know who really pushed the early cell phones, and was leaps ahead od the US? Ericcson and Nokia, Swedish and Finnish companies. Apparently, they were very early adopters of cell phones, because they are both Very large countries, each with a couple denser areas, and scattered very low density areas. They were able to run a fiber (or copper in the earlier era) out to cell towers, and then feed something like a 25 mile radius out from the tower.

Point being; I could see micro solar package plants, being a very good option in India, much of Africa, Egypt, the northern 'Stan's, ect. Where the base infrastructure is limited. If we say a package solar plant could be shipped in 4 containers, (easily slung off a Mi-26 were roads are limited), and power up a hundred village center, for a reasonable rate. I'm not talking about 5000 acre solar farms; I'm talking about lights in maybe 8 commercial-gov buildings, a well pump, and water treatment, and maybe 20 amps worth to the closest residences.

Some super dirty, fast numbers, you could provide something like a very limited supply. to roughly 160 homes per acre of panels. Note; I'm not talking US homes, I'm talking about a light bulb or two, some USB charging, and a fan.

My second home had all the typical comforts and still has 120 volt 30amp service… of course gas heat, hot water, cooking and dryer makes it doable…

I managed a triplex with 3 studio units of wartime construction with a single 120 volt 30 amp shared meter… only problem was portable electric heaters but each unit individually gas mattered.

 

[Oaktree]

With out going to far down a rabbit hole; was speaking with an engineer for a large power company about a problem, work involved. He has a single customer, dead end line, feeding an abandoned house, that he has to spend something like $160k to replace the feed too.

Not sure I follow you, why is he maintaining electric service to an abandoned building?

 

[ponytug]

Article from 2019:

https://www.tesla.com/blog/introducing-megapack-utility-scale-energy-storage

The Australian megapack deployments are for time shifting solar to make the grid more reliable. They absorb solar power 10-3 and then act as peaker plants to support the grid 4-10pm.

Tesla Megapack 2XL to power new giant 877 MWh Neoen battery project

The Tesla Megapack 2XL is going to power a new giant 877 MWh battery project developed by France’s Neoen in...

electrek.co

(877MWh of capacity)

Tesla Megapack to power new massive record-breaking 1.3 GWh battery system

Tesla Megapack has been selected to power a massive new record-breaking 1,3 GWh battery system from Neoen in Australia. This...

electrek.co

(1,200MWh capacity)

The currently (pun intended) largest version of this peaker battery storage system is on the California coast, not too far from here;

The world’s largest battery storage system just got even larger

The Moss Landing Energy Storage Facility, the world's largest battery storage system, has been expanded to 750 MW/3,000 MWh.

electrek.co

(3,000MWh of capacity)

These systems all help smooth out the difference in energy supply and demand. I suspect that as more renewables come on line, and more energy is used as electricity, there will be other versions of this, e.g. electrically heating brick piles for thermal energy storage (to lower the cost of things like baking and metal working, and simpler versions to store energy at home), and chemically storing the energy, e.g. hydrogen production for use in chemical manufacturing, or fuels, though not necessarily as hydrogen. There are also refrigeration versions as well, where you can freeze large blocks of ice for later use in cooling. A company, Thule energy, makes systems for small businesses, though they used to make a homeowner sized unit. Stanford University built one in the 80s that was so successful that they built a second, much, much larger version to provide heating and cooling for the entire campus and hospital systems.

Central Energy Facility

The Central Energy Facility houses the innovations of Stanford’s Energy System Innovations (SESI): heat recovery technology, thermal storage tanks, thermal energy distribution network, and patented operational optimization software.

sesi.stanford.edu

If you know that energy is going to be 5-10% of the cost from 2-4 than it would be from 4-10pm, it starts to make economic sense to use more energy then.

All the best,

Peter