Thoughts on mega wind and solar projects

[Phil Timmons]

@Phil Timmons just for reference for here, 16kW ground mount, low end quote was $65k three years ago. That's close to double to triple roof mounted solar in this area.

Roof PV is plug and play at the planning offices. Ground mounts all require signoff from multiple engineers, which increases the price, and unless you are a PE and can sign your own plans.

Very much "YMMV"!

All the best,

Peter

Tends to be a case-base on the Contractors. Some specific skills contractors do roofs. Others do ground. You want to shop for the ones that do what you need. Like you would not want to hire a car painter to paint your living room. Or something. Dunno. Just find the folks that actually do what you want. Not the ones who run up a price just to get you to pick something else. Sort of funny -- I do that with roofs. I call it "Sharing the PITA." (PITA being in Pain in the @ss).

Our numbers are down in the $1 to $2 per Watt range -- full install -- but do not let the customers get too wild on what they get. Sort of like Henry Ford was supposed to say of the Model T? You can have any color you want as long as it is Black.

But, yeah, as far as PEs -- it is part of the game. Both roof and ground. We have three EE, and two Structural. Some places need neither, some both, and some one or the other. I am a 30+ year Master, so I generally have the permitting covered. I never argue with a building inspector, and get things checked before hand, so life is easy.

The real difference for Ground v. Roof is really about (the real words) On-a-Building (Building Code, duh huh?) v. a "Structure" that is NOT a Building. Keep it OFF the Building and the Building Issues (of National Electrical Code) do not apply. The specific terms are Rapid Shutdown. That was some sleaze recently added to the NEC. Costs about $100 more per panel to put on a roof.

Got so tired of having to explain this so many times -- I put some sketches on line, just so folks can know what they can get without me having to do entire essays after someone thinks they already know everything from listening to a discussion on talk-radio, or wherever the retardation spreads from. Just been too busy to update this page, but maybe I should get a kid to do so? These are all $1 per Watt, full install.

Electric Farming Company Home Page

Your "quote" example was $4 per watt (or so, right?). But that was just "a quote," right? I mean you did not "buy" at that price point, right? You follow where this is going? That may be a quote, but is NOT a sales price, as no such sale occurred? I am asking, not saying? For example -- catch a little of this video, parallel product, good for perspective. -- anyone can quote any price. But that does not mean there is any such sale.

 

[ponytug]

@Phil Timmons Yes, I didn't bite at the price. In shopping around that was the lowest of the quotes received. One group did something unique in my experience. They quoted it, and then about four days later called to say that they had thought about it and decided that the job was beyond them, and they would like to pull the quote. (And it is not as if I want an unwilling contractor doing work for me...)

All the best,

Peter

 

[hoozie]

~16 months ago I installed solar on our house from Project Solar. They do the site plans and file the plans with the utility and the county, then send you a pallet of panels and parts. You supply any conduit and wires.

8kw in panels (but only 6kw in micro-inverters) and Enphase control boxes was around $15k. Then the 30% tax credit.

In that time it's generated 2.5MWh, or roughly $2250 in electricity.

Edit: WOOPS! It's actually generated 12.7MWh, not two and a half

 

[Phil Timmons]

@Phil Timmons Yes, I didn't bite at the price. In shopping around that was the lowest of the quotes received. One group did something unique in my experience. They quoted it, and then about four days later called to say that they had thought about it and decided that the job was beyond them, and they would like to pull the quote. (And it is not as if I want an unwilling contractor doing work for me...)

All the best,

Peter

That is interesting that they were wise enough to know that they did not know.

The rough target numbers we are working towards are around $1 per Watt -- but I do not mind it slipping up to $1.50 to close to $2.00 if they are trying to so some weird. But in terms of money -- if they are doing anything weird it is just going to hurt them.

The entire "TRICK" is in keeping the Starting Cost as low as possible.

But as noted above -- $4 per Watt . . . is a ways out there.

=======================

The money math (local, here, Texas is):

"Payback" Model:
$1 per Watt x (size in Watts) = Project Cost.
Total Watts x (2000 hours)* = Annual Production in Watt-hours
Then compare to Watt-hour price and billing for present Utility Billing.

Example: (typical 10kW system)
$1 per Watt x 10kW = $10,000 Project Cost.
10000 Watts x 2000 hours = 20000000 Watt-hours per year, or 20,000 kWh.

for a Local Retail Price = $0.15 per kWh, that works out to:
20,000 kWh x $0.15 = $3000 avoided Utility Billing per year.
$10000 / $3000 per year = 3.3 years to "Payback" and then FREE for 20 or more years.

Full back in 3.3 years works out to a 23% Annual Return On Investment. And then near infinite ROI for follow on years, as it continues operating for $0 additional costs.

I am not really fond of that "Payback" modeling. It often does include whether there are meter fees, full net-metering or other things that are part of the total cost of ownership.

=======================

Cost of Production Model. (since I have Utility Engineering background, I am more inclined to use this model)

Service Life = 25 years. (just a base number. If folks will KEEP IT OFF THE ROOF, then 40 years with minimal Operations & Maintenance is practical).

20,000 kWh (Annual production from above model) x 25 Years = 500,000 kWh.

$10,000 / 500,000 kWh = $0.02 per kWh.

There has never been another generation source this cheap. Most every other Utility Electrical Engineer has done this same math -- and that is why US is now mostly building Solar PV for anything new on US Grid.

In practice, for "Real World" people and real sites, I think we should include potential Meter Fees (for Grid Tie) and some Time-Value of Money on the starting "investment" ($10,000 in our model), so I round things up to as much as 3 cents per kWh.

So cost of Local Production is about 2 to 3 cents per kWh, "Behind the Meter," for the next 25+ years. This is typically about 1/5 or less the cost of Retail. Most predictions show the long-term Cost of Retail going up -- so this is a wise investment if one is planning to stay alive for a few more years and use Electricity.

================

*2000 Hours. This is a production modeling number. Typical US Solar PV is around 25% "Capacity Factor" of the Nameplate, across an 8760 hour year. True 25% would be 2190 hours. I am dropping it down to 2000 hours to allow for conversion losses, equipment age, etc.

 

[MossRoad]

 

[Phil Timmons]

yep. And once we get the farmer-folks smart enough to USE that local produced "fuel" instead of paying for Oil from afar . . . US can win this biggly.

 

[rontaki]

I'm happy for her that the wind generation enables her to keep the farm.
I'm also concerned about out future, return things hey to this point. Extrapolating, future humans will have to live on electricity, not food as we know it.

 

[Eagle1]

I'm happy for her that the wind generation enables her to keep the farm.
I'm also concerned about out future, return things hey to this point. Extrapolating, future humans will have to live on electricity, not food as we know it.

AI and robotics are the future, for the select humans...

 

[sd455dan]

~16 months ago I installed solar on our house from Project Solar. They do the site plans and file the plans with the utility and the county, then send you a pallet of panels and parts. You supply any conduit and wires.

8kw in panels (but only 6kw in micro-inverters) and Enphase control boxes was around $15k. Then the 30% tax credit.

In that time it's generated 2.5MWh, or roughly $2250 in electricity.

Our PoCo must charge a whole lot less per KWH, that is an excellent amount of savings for your investment.

@Phil Timmons just for reference for here, 16kW ground mount, low end quote was $65k three years ago. That's close to double to triple roof mounted solar in this area.

Roof PV is plug and play at the planning offices. Ground mounts all require signoff from multiple engineers, which increases the price, and unless you are a PE and can sign your own plans.

Very much "YMMV"!

All the best,

Peter

Yikes, that is more than the 24KW of solar I have currently installed, a 12KW Hybrid Inverter, and 101 KWH LiFePo battery bank, plus back up if the 18K PV dies, 5 Schneider 6848 Pro inverters ,back up control switch, Power distribution panel etc.

My main array has produced 18 MWH in 14 months. The other strings are through a separate MPPT so I don't have good numbers on it/them.

That is interesting that they were wise enough to know that they did not know.

The rough target numbers we are working towards are around $1 per Watt -- but I do not mind it slipping up to $1.50 to close to $2.00 if they are trying to so some weird. But in terms of money -- if they are doing anything weird it is just going to hurt them.

The entire "TRICK" is in keeping the Starting Cost as low as possible.

But as noted above -- $4 per Watt . . . is a ways out there.

=======================

The money math (local, here, Texas is):

"Payback" Model:
$1 per Watt x (size in Watts) = Project Cost.
Total Watts x (2000 hours)* = Annual Production in Watt-hours
Then compare to Watt-hour price and billing for present Utility Billing.

Example: (typical 10kW system)
$1 per Watt x 10kW = $10,000 Project Cost.
10000 Watts x 2000 hours = 20000000 Watt-hours per year, or 20,000 kWh.

for a Local Retail Price = $0.15 per kWh, that works out to:
20,000 kWh x $0.15 = $3000 avoided Utility Billing per year.
$10000 / $3000 per year = 3.3 years to "Payback" and then FREE for 20 or more years.

Full back in 3.3 years works out to a 23% Annual Return On Investment. And then near infinite ROI for follow on years, as it continues operating for $0 additional costs.

I am not really fond of that "Payback" modeling. It often does include whether there are meter fees, full net-metering or other things that are part of the total cost of ownership.

=======================

Cost of Production Model. (since I have Utility Engineering background, I am more inclined to use this model)

Service Life = 25 years. (just a base number. If folks will KEEP IT OFF THE ROOF, then 40 years with minimal Operations & Maintenance is practical).

20,000 kWh (Annual production from above model) x 25 Years = 500,000 kWh.

$10,000 / 500,000 kWh = $0.02 per kWh.

There has never been another generation source this cheap. Most every other Utility Electrical Engineer has done this same math -- and that is why US is now mostly building Solar PV for anything new on US Grid.

In practice, for "Real World" people and real sites, I think we should include potential Meter Fees (for Grid Tie) and some Time-Value of Money on the starting "investment" ($10,000 in our model), so I round things up to as much as 3 cents per kWh.

So cost of Local Production is about 2 to 3 cents per kWh, "Behind the Meter," for the next 25+ years. This is typically about 1/5 or less the cost of Retail. Most predictions show the long-term Cost of Retail going up -- so this is a wise investment if one is planning to stay alive for a few more years and use Electricity.

================

*2000 Hours. This is a production modeling number. Typical US Solar PV is around 25% "Capacity Factor" of the Nameplate, across an 8760 hour year. True 25% would be 2190 hours. I am dropping it down to 2000 hours to allow for conversion losses, equipment age, etc.

Seems overly optimistic for the payback and also KWH generated over a year for most, especially in less sunny areas.
I wish my production was that good. Way to many cloudy and rainy days per year. Now if we lived in Sun City Arizona those numbers look likely.

 

[Phil Timmons]

It is US average. 25% Capacity Factor, I mean.

Some parts of US -- California, Texas, Georgia (yeah, Georgia -- out performs Arizona) run above average. And other places less. You can "boost" Northern Tier States with Tracking and Reflectors.

For numbers specific to any given location, this is a pretty good reference. It even has month-by-month production for a typical year. Ran some numbers against it a few years ago, and was generally within 1%. >>

PVWatts

Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations

pvwatts.nlr.gov

 

[sd455dan]

It is US average. 25% Capacity Factor, I mean.

Some parts of US -- California, Texas, Georgia (yeah, Georgia -- out performs Arizona) run above average. And other places less. You can "boost" Northern Tier States with Tracking and Reflectors.

For numbers specific to any given location, this is a pretty good reference. It even has month-by-month production for a typical year. Ran some numbers against it a few years ago, and was generally within 1%. >>

PVWatts

Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations

pvwatts.nlr.gov

Trackers are nice but even more money than tiltable arrays. The tilt does help for sure. I went with Sinclair Skyrack after another member here recommended them. One of the best decisions for sure, but it did cost 2k to ship it.

 

[Phil Timmons]

Trackers are nice but even more money than tiltable arrays. The tilt does help for sure. I went with Sinclair Skyrack after another member here recommended them. One of the best decisions for sure, but it did cost 2k to ship it.

Do you get much snow? Did some designs for Colorado that were "self-dumping" as part of the tilt.

The weight of the snow changed the balance point to allow it to dump, and then could reset after the snow was dumped.

I went embarrassingly cheap on the whole tilt-tracker option. Our only question is if we should build them in Mexico and drive them back?

Electric Farming Company Home Page

 

[hoozie]

Our PoCo must charge a whole lot less per KWH, that is an excellent amount of savings for your investment.

Woops, see my edit: my array has produced 12.7MWh lifetime. Retail rate looks to be about 17c/kwh (last bill was $265 for 1577 net kwh).
The big dip in February '25 was when we got 5' of snow in a week.

It's been a good investment, but I still need more panels, lol.

daily production since it got turned on:

 

[sd455dan]

Working with a battery today, adding active balancing and experimenting with 60 watt heat pads and a controller.

We finally had some sun peeking through recently, pretty good output from the 14.4 KW array

 

[sd455dan]

Do you get much snow? Did some designs for Colorado that were "self-dumping" as part of the tilt.

The weight of the snow changed the balance point to allow it to dump, and then could reset after the snow was dumped.

I went embarrassingly cheap on the whole tilt-tracker option. Our only question is if we should build them in Mexico and drive them back?

Electric Farming Company Home Page

Really depends on the year. Barely counts as a winter this year, 2022 was like what some of the east seaboard got lately.

 

[ponytug]

Working with a battery today, adding active balancing and experimenting with 60 watt heat pads and a controller.

We finally had some sun peeking through recently, pretty good output from the 14.4 KW array

16kW is impressive.

What is the first photo? A battery you are building?

All the best,

Peter

 

[sd455dan]

16kW is impressive.

What is the first photo? A battery you are building?

All the best,

Peter

No that is one of the inexpensive discount imports, 280 AH 51 Volt LiFePo 4 from eco-worthy.

The EG 4 280 Power Pros have UL listing, heaters, and fire suppression built in. These are more basic, come with good cells and I paid less for two delivered than a single Power Pro without shipping. I am still looking into the fire suppression kits. The $50 active balancer is better than what the EG 4's presently have as well (easily smart balance individual cells within .003V quickly). Already have had one of these batteries in service over a year so far and it has been decent.

 

[ponytug]

No that is one of the inexpensive discount imports, 280 AH 51 Volt LiFePo 4 from eco-worthy.

The EG 4 280 Power Pros have UL listing, heaters, and fire suppression built in. These are more basic, come with good cells and I paid less for two delivered than a single Power Pro without shipping. I am still looking into the fire suppression kits. The $50 active balancer is better than what the EG 4's presently have as well (easily smart balance individual cells within .003V quickly). Already have had one of these batteries in service over a year so far and it has been decent.

That's a battery! Quite the capacity. Thanks for sharing that.

All the best,

Peter