Grid-tied solar

[newbury]

An average solar PV panel puts less than 3 pounds per sq. ft. load on a roof. Not nearly enough to cause roof collapse.<snip>

I wasn't referring to roof collapse due to the weight of a correctly designed system but rather due to shoddy construction. In a prior time I worked as a roofer for several years and have seen some very shoddy construction in additions and modifications. Very often leaks develop due to improper flashing. Leaks cause wood to rot.

There are a lot of homeowners that don't like to clamber up two or three stories to double check all the flashing etc.

 

[Redneck in training]

Never seen a battery fail early in 30 years?? I'm not even going to touch that as it's either a play on words or something else.
If you set your panels vertical for NE winter to shed snow, you loose effective surface area.
It's subsidized because it has to be, because it costs more. They have to improve the 80% energy loss before it becomes economical in the north east.

I used to work for telecom about 10 years while I had a second job installing and replacing "station" batteries (200 Ah and up). The typical telephone switch battery lasted at least 25 years. That was about 40 years ago. Since then the battery and especially charging technology improved substantially. I believe that batteries might last 20 years or more.

 

[dave1949]

Dave, You must be joking when you say PV panels don't need to be subsidized...
With taxpayer subsidies, you are looking at 15-22 years to break even. Drum roll please....
That's a bad business investment no matter how you slice it. Then you have a worn out 20 year old system then what?
Don't get me wrong, I like it, just don't like people tring to sell it to people on the grid with false promises of saving $$.
Right now it's a hobby for people and that OK. Maybe some day there will be a tech breakthrough I hope.

No, not joking.

I hope I have been very straight forward about costs, see post #37 for example. It isn't an investment, it is a front-loaded cost replacement. I sure don't expect to make a dime on it, others may due to the markets for renewable energy credits which are state-specific. I do hope I will be in the break-even area at the end of the system life. At that point, it will be time to replace it with something newer and start over again.

In my particular case, replacing the water heater involved plumbing and electrical work. I don't have an itemized bill, but I would say that accounted for about $2K of my total cost that should not be counted toward the electrical payback period in the strict sense. I count it because it was part of my total project goal.

If 20 years from now, I can say I avoided burning 5,200 gal. of propane, produced some of my other electricity needs, and my net costs were very low, I will be happy, and doubly happy if I am alive to see that :laughing:

Let's say I come up $2K short of netting out to zero. Over 20 years that is $100 per year. I'll bet most of us pi** away that much and more every year. It's good to keep a perspective.

 

[dave1949]

I wasn't referring to roof collapse due to the weight of a correctly designed system but rather due to shoddy construction. In a prior time I worked as a roofer for several years and have seen some very shoddy construction in additions and modifications. Very often leaks develop due to improper flashing. Leaks cause wood to rot.

There are a lot of homeowners that don't like to clamber up two or three stories to double check all the flashing etc.

Good point. Just because a house has a roof, doesn't mean it is a suitable roof, and all roof penetrations need to be done correctly and maintained.

 

[madmax12]

No, not joking.

I hope I have been very straight forward about costs, see post #37 for example. It isn't an investment, it is a front-loaded cost replacement. I sure don't expect to make a dime on it, others may due to the markets for renewable energy credits which are state-specific. I do hope I will be in the break-even area at the end of the system life. At that point, it will be time to replace it with something newer and start over again.

In my particular case, replacing the water heater involved plumbing and electrical work. I don't have an itemized bill, but I would say that accounted for about $2K of my total cost that should not be counted toward the electrical payback period in the strict sense. I count it because it was part of my total project goal.

If 20 years from now, I can say I avoided burning 5,200 gal. of propane, produced some of my other electricity needs, and my net costs were very low, I will be happy, and doubly happy if I am alive to see that :laughing:

Let's say I come up $2K short of netting out to zero. Over 20 years that is $100 per year. I'll bet most of us pi** away that much and more every year. It's good to keep a perspective.

That's a mature perspective. If solar is a "cause" and a potential money saver, it is doubly worth it to the "investor."

 

[EE_Bota]

If I were not on the north side of a hill with high trees behind me owned by my neighbor, I'd have solar for sure. I don't worry about the payback so much. I'd like having it around, monitoring it, installing it, and whole deal. I am considering moving just to get a flatter place, with more land, and one more conducive to such projects.

My all electric home power bill only costs me around $65/month in the summer, and ~$120 in the winter, but I do burn some wood. And I continue to try to drive those numbers down. First best money for me would still be more insulation...but not nearly as fun as solar and I do like fun as much as the next guy. And life just keeps getting shorter.

 

[meburdick]

I didn't consider them. They aren't compatible with my standing seam metal roof. Maybe in the right climate, they could be worth a look.

I have no idea what their life expectancy is, and the thin-film PV is not as efficient as the solid crystalline types unless they have made a lot of progress in that area. The trade-off is low production costs, but if their life is short, or not efficient enough to offset the low cost, you might have something that is a poor shingle and a poor PV panel. I would have to hear some local success stories before considering them.

In this area, I would be concerned about snow and ice build-up. What happens when a roof rake is used to clear the snow, for example.

Just making a guess here... I would suspect that solar shingles are best-suited for climates that do not get snow, get significant sunshine, and the architecture allows for the appropriate angle to get good efficiency from them. In addition, would you install these on the whole roof or only on large surfaces that face South to maximize sun exposure?

Efficiency doesn't matter.

If efficiency was always the driving force behind energy use, we wouldn't be driving cars powered by gasoline engines.

No, not joking.

I hope I have been very straight forward about costs, see post #37 for example. It isn't an investment, it is a front-loaded cost replacement. I sure don't expect to make a dime on it, others may due to the markets for renewable energy credits which are state-specific. I do hope I will be in the break-even area at the end of the system life. At that point, it will be time to replace it with something newer and start over again.

VERY front-loaded at that... And, what will the cost be to replace the system in 20 to 25 years when the subsidies are gone?

My front-loaded replacement system was to install a 75,000 BTU wood-burning insert into my fireplace and save $3,000 / year on fuel oil for heating. Considering I paid $4,500 for the insert, installation, and the chimney pieces, the system is completely paid for in 1.5 burning seasons. I got a manufacturer rebate, and because the efficiency level was so high, I also got a tax credit... That reduced my cost recovery time to about 1.3 burning seasons. When solar approaches these sort of cost recovery timeframes, they'll be highly adopted.

 

[madmax12]

Just making a guess here... I would suspect that solar shingles are best-suited for climates that do not get snow, get significant sunshine, and the architecture allows for the appropriate angle to get good efficiency from them. In addition, would you install these on the whole roof or only on large surfaces that face South to maximize sun exposure?



If efficiency was always the driving force behind energy use, we wouldn't be driving cars powered by gasoline engines.



VERY front-loaded at that... And, what will the cost be to replace the system in 20 to 25 years when the subsidies are gone?

My front-loaded replacement system was to install a 75,000 BTU wood-burning insert into my fireplace and save $3,000 / year on fuel oil for heating. Considering I paid $4,500 for the insert, installation, and the chimney pieces, the system is completely paid for in 1.5 burning seasons. I got a manufacturer rebate, and because the efficiency level was so high, I also got a tax credit... That reduced my cost recovery time to about 1.3 burning seasons. When solar approaches these sort of cost recovery timeframes, they'll be highly adopted.

Well, you have good points and reasons, IMO. We certainly don't all view world issues exactly the same. I imagine many here (including me) have a huge stash of wood, and a woodstove, or the like. However, I hope for the potential and the improvement of wind and solar. The more options we have, that are truly in place and functional, the better off any society making use of them, peaceably, will be. And the rules change, alot. In the 70's, electric heat was all the rave... then oil tanked, and made converting to oil, the next big thing. I'm enjoying learning from the variety of contributors on this site. Many great people, with incredible insight, vision, and ingenuity.

 

[dave1949]

VERY front-loaded at that... And, what will the cost be to replace the system in 20 to 25 years when the subsidies are gone?

My front-loaded replacement system was to install a 75,000 BTU wood-burning insert into my fireplace and save $3,000 / year on fuel oil for heating. Considering I paid $4,500 for the insert, installation, and the chimney pieces, the system is completely paid for in 1.5 burning seasons. I got a manufacturer rebate, and because the efficiency level was so high, I also got a tax credit... That reduced my cost recovery time to about 1.3 burning seasons. When solar approaches these sort of cost recovery timeframes, they'll be highly adopted.

Who knows what will be available 20-25 years from now? A handful of people in Japan are buying natural gas-supplied home fuel cells at about $64,000 each

Never say never, but I doubt solar electric generating systems will ever have short payback periods. You can't run a light bulb from an insert wood stove, and solar PV is a poor choice for home heating. We aren't really comparing apples to apples.

You made a very good move financially, for energy independence, comfort and for it's green value.

But...

I don't know what you included in your cost to replace the $3000 in oil. It should include the wood, purchase or own labor, if labor then there is a chainsaw, truck/trailer/tractor, keeping it dry, toting it, emergency room , etc. Your stove will be ready to be replaced or rebuilt in 20 years or sooner too, and you will probably be on your second or third circulating fan by then, and chimneys need maintenance and don't last forever. I think your continuing costs will be much higher than a solar system's.

Your upfront costs and annual costs are reachable by many more people. I don't say that dismissively, it's just an economic fact. That's more of a financial problem than technical, and there is no easy solution. Right now, leased solar PV systems are the only thing on the horizon to address that.

 

[meburdick]

Never say never, but I doubt solar electric generating systems will ever have short payback periods. You can't run a light bulb from an insert wood stove, and solar PV is a poor choice for home heating. We aren't really comparing apples to apples.

You made a very good move financially, for energy independence, comfort and for it's green value.

But...

I don't know what you included in your cost to replace the $3000 in oil. It should include the wood, purchase or own labor, if labor then there is a chainsaw, truck/trailer/tractor, keeping it dry, toting it, emergency room , etc. Your stove will be ready to be replaced or rebuilt in 20 years or sooner too, and you will probably be on your second or third circulating fan by then, and chimneys need maintenance and don't last forever. I think your continuing costs will be much higher than a solar system's.

Your upfront costs and annual costs are reachable by many more people. I don't say that dismissively, it's just an economic fact. That's more of a financial problem than technical, and there is no easy solution. Right now, leased solar PV systems are the only thing on the horizon to address that.

No, you can't run a light bulb from a wood stove, and it isn't a good comparison of ways to implement solar. The point I was making was that there are other areas where we have to invest money up front to get savings, and the savings comes MUCH faster.

I burn about 6 cord of wood per year. I buy it in log length for roughly $100 / cord. I have a $800 wood splitter, a $300 chain saw, and will spend about $50/year in fuel for the saw, splitter, and tractor (to move the wood on pallets) for cutting, splitting, and stacking. In total, my investment for the year in wood is somewhere in the $700 range.

By way of comparison, a cord of wood replaces an average of 175 gallons of oil (lots of factors have to be considered to get a fully accurate number: burner efficiency, type of wood, water content, etc - but 175 is a good "working number"). That totals out to 1050 gallons of oil. At $3.50/gallon (cheap during heating season in the northeast), that's $3,675 in oil. Subtract out the $700 I spend for the wood, and you're just shy of $3,000 every heating season.

Put better, I save somewhere around 80% by heating primarily with wood. That's a more useful number because the cost of wood increases in relation to the cost of oil. If oil were to double, you could expect the cost of wood to double. I would still save 80% although the dollar amount would increase to almost $6,000. :shocked: