Solar production. Panel ratings/claim vs reality

[sd455dan]

Guess I will get into the solar thing as well. As much for backup power as reducing grid use, so going with Hybrid inverter/ batteries and bifacial panels.


Rechecked my bills and I misquoted our rates in the ev thread, base rate of 8.23 cents KWH for the first 1250 KWH and .1028 above that. Our electric power co-op will buy back over production at 4 cents a KWH.

 

[fatjay]

Guess I will get into the solar thing as well. As much for backup power as reducing grid use, so going with Hybrid inverter/ batteries and bifacial panels.


Rechecked my bills and I misquoted our rates in the ev thread, base rate of 8.23 cents KWH for the first 1250 KWH and .1028 above that. Our electric power co-op will buy back over production at 4 cents a KWH.

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.

 

[sd455dan]

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.

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.

 

[paulsharvey]

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.

The power company has significant cost in the design, construction, and maintenance of the infrastructure. If they paid you they charge customer distribution rates; every watt hour You generated would cost them probably 25% more than they can pass down the line.

 

[ultrarunner]

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.

Just thinking out loud, reading this thread with interest.

I only adjust angle of my panels twice a year…

 

[Grumpycat]

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.

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.

 

[Grumpycat]

The power company has significant cost in the design, construction, and maintenance of the infrastructure. If they paid you they charge customer distribution rates; every watt hour You generated would cost them probably 25% more than they can pass down the line.

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".

 

[ultrarunner]

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".

For decades PGE always cited the high cost of generation as basis to raise rates… building, operating, fueling, etc.

Then home solar comes along and about face… the cost of generation is incredibly low but now it’s distribution that is so expensive.

All I know is the little guy always pays in the end…


Now they want to means test customers across the board so higher income residences will pay more…

 

[ponytug]

Guess I will get into the solar thing as well. As much for backup power as reducing grid use, so going with Hybrid inverter/ batteries and bifacial panels.


Rechecked my bills and I misquoted our rates in the ev thread, base rate of 8.23 cents KWH for the first 1250 KWH and .1028 above that. Our electric power co-op will buy back over production at 4 cents a KWH.

If you want solar for backup, I would make sure that you design that in. Some inverters and microinverters are grid forming and can function during outages, but most can't. For starting larger loads, having battery storage helps, and is necessary for overnight uses.

My $0.02 is plan a system that includes batteries that can be recharged from the generator for those winter blizzards, and summer fires that shutdown solar production.

All the best,

Peter

 

[sd455dan]

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.

Have you decided on a system, Last post think I saw you were considering Tesla power walls or EG4 ?

If you want solar for backup, I would make sure that you design that in. Some inverters and microinverters are grid forming and can function during outages, but most can't. For starting larger loads, having battery storage helps, and is necessary for overnight uses.
My $0.02 is plan a system that includes batteries that can be recharged from the generator for those winter blizzards, and summer fires that shutdown solar production.

All the best,

Peter

Right or Wrong, I pulled the trigger on a 'DIY' EG4 kit, 12KW output hybrid inverter, 18k PV input, 28.6 KWH battery power, Panels , 450 watt (540 watt max) 41" x 7' and heavy @68lb. but they did do Very well in the Ice ball impact testing and are a Tier 1 manufacturer.

PV DC into the Inverter

Inverter has pass through for a full 200 amp grid service which I do need It can also be paralleled with more 18kpv's if wanted. Rated PV is 14.4KW (32 bifacial panels) but probably be lucky to get 1/2 of that in output up here I would guess.

 

[Grumpycat]

Have you decided on a system, Last post think I saw you were considering Tesla power walls or EG4 ?

Talked to 2 Tesla Solar vendors, got quotes, perhaps made the mistake of letting them know I have a Tesla.

Meet with non-Tesla vendor tomorrow, will drive F-150. He seems to have used whatever the customer choses. The EG4 18kW and matching EG4 battery you selected is high on my list. Sol-Ark is interesting but he has been having problems with the 15k communicating with different brands of batteries. And the Sol-Ark is more expensive.

Right or Wrong, I pulled the trigger on a 'DIY' EG4 kit, 12KW output hybrid inverter, 18k PV input, 28.6 KWH battery power, Panels , 450 watt (540 watt max) 40" x 7' and heavy @68lb. but they did do Very well in the Ice ball impact testing and are a Tier 1 manufacturer.

PV panel brand/model? Sounds very similar to what I think I'll end up with. However I'm leaning toward (2) hybrid inverters and 1 battery each, for redundancy.

 

[sd455dan]

Talked to 2 Tesla Solar vendors, got quotes, perhaps made the mistake of letting them know I have a Tesla.

Meet with non-Tesla vendor tomorrow, will drive F-150. He seems to have used whatever the customer choses. The EG4 18kW and matching EG4 battery you selected is high on my list. Sol-Ark is interesting but he has been having problems with the 15k communicating with different brands of batteries. And the Sol-Ark is more expensive.


PV panel brand/model? Sounds very similar to what I think I'll end up with. However I'm leaning toward (2) hybrid inverters and 1 battery each, for redundancy.

Exactly what I read on the battery communications with SolArk, but have also read the SolArk is a more polished unit especially in other software areas.

I probably jumped the gun on ordering but want to get the panels, trenching and system installed before winter and only have limited help. I have mixed feelings on EG 4 but the price is better than anyone else. Sometimes hard to tell when complaints are actual owners or a competitor brand just trying to slow a competitors sales.

Ordered from Signature Solar , their service and tech help is improving and the 18k PV seems to have most software bugs worked out after the last couple years as well, but the forums feedback years previous is not what most would call stellar. I like Tesla and their power walls but to get anywhere near the PV and battery back up would be a lot more money.

The panels were an option in their kit choices- Boviet 450 watt (540 watt max) 1/2 cell perc bifacials. ( wanted Aptos but tech said no stock until October) Having a few second thoughts on who I bought from, A1 solar or Current Connected likely would have been a better choice for after sales service, but free shipping is also included with buying from Signature.

I like your plan on paralleling two EG 4 18K PV's if you do go that way. If I get any shut downs due to overcurrent on the single 18K PV will likely have to go that route in the future. Who knows, but it Will be a learning experience for me and being a bit more self sufficient is a good thing imo.

 

[ultrarunner]

My components date from 2009 and I never did any programming.

Components USA and Germany…

 

[ning]

being a bit more self sufficient is a good thing imo

Can't argue with that - but the caveat must be stated that most grid failures happen with bad weather, and bad weather typically greatly reduces solar power produced.

I expect that if I manually ration my usage I may be able to stretch 30kWh of battery backup into three days if I'm lucky - I used to be able to use a 3kW generator for well & fridges & freezer backup - but it would actually be more of a pain than using the generator right now because my entire house is backed up now instead of just plugging in specific circuits using the little genset was. Pretending the grid is still on, and getting no solar recharge, it would last about a day (winter we typically have less power use than most of the rest of the year - gas water heater, gas furnace, wood stove, gas range, gas dryer - still need electricity for those, but not a lot).

I'm planning to add a whole house generator for winter backup - it'll interface to the battery charging system so it'll only run when the batteries need recharging; a 250 gallon (nominal) propane tank should provide 3-4 weeks of careful backup (unplug everything, be very careful what you turn on, etc) with next to no solar recharge.

 

[ericm979]

Power goes out at my California place a lot. Usually there's at least one week long outage per winter, sometimes more.

My neighbors built an ADU and set it up for outages. It's got solar and batteries but also they can top off the batteries with a generator. Even in winter when it's raining they only need to run the generator for a few hours a day to top the batteries up.

 

[ultrarunner]

Power goes out at my California place a lot. Usually there's at least one week long outage per winter, sometimes more.

My neighbors built an ADU and set it up for outages. It's got solar and batteries but also they can top off the batteries with a generator. Even in winter when it's raining they only need to run the generator for a few hours a day to top the batteries up.

I've heard the power has issues in the Santa Cruz mountains...

Friends live on Lady Chance road off grid 40 years now... put they have a telephone 7 miles from paved road.

 

[ning]

I've heard the power has issues in the Santa Cruz mountains...

Friends live on Lady Chance road off grid 40 years now... put they have a telephone 7 miles from paved road.

When I lived in Santa Cruz in the 80's and 90's - actually in the city - I used to joke that SC had third world power, it went out so much. Not typically long outages then, but seriously it seemed like we'd lose power here or there for a couple hours at least once a month and it didn't seem to follow weather. Hopefully at least the city has better power now but who knows. Moved up to the Sierra foothills and power vastly improved, other than specific storm-caused outages which I grew up with in a small town further north.

 

[ericm979]

I've heard the power has issues in the Santa Cruz mountains...

It's a hard environment for power delivery. The mountains are steep, the trees are big, the ground is loose, and it rains a lot. It's hard on roads too.

PG&E being a terrible company makes it worse but it'd be bad with any power company.

 

[Grumpycat]

My components date from 2009 and I never did any programming.

Components USA and Germany…

The combination hybrid PV inverter and battery inverter would like guidance as to whether it should charge battery and use low TOU grid power, or to feed the grid. Is possible to charge the battery from PV at one time of the day then feed the grid from the battery when TOU is high and utility pays most. And a lot more options than that.

Hybrid inverters do not require PV. Can install in Kalifornia to charge battery during low TOU to minimize costs during high TOU periods.

 

[ponytug]

It's a hard environment for power delivery. The mountains are steep, the trees are big, the ground is loose, and it rains a lot. It's hard on roads too.

PG&E being a terrible company makes it worse but it'd be bad with any power company.

I agree that it is a tough environment.

The redwoods have a tendency drop limbs at random intervals, and for better or worse, utility lines have fairly narrow trimming distances.

Not a great combination for reliable power, but I think that it is very peaceful and pretty when it is green.

All the best,

Peter