Grid-tied solar

[fordmantpw]

Paying 30 cents a kWh has an impact and changes things compared to someone paying 10 cents... just saying.

Absolutely!

 

[houstonscott]

Selling back never seems to be a worthwhile proposition. For me, I'm on a co-op, and it doesn't buy anything back, no matter how much you are over, so there is no benefit to over-producing. Plus, there is a minimum just for having a meter, so for me, the best place to be is about 80-90% replacement of electricity. Active trackers don't seem to be worth the added expense. When we built our new home, I had my shed built with solar in mind. 5/12 pitch roof (optimal is 6/12, but that's a bit steep for a metal roof, plus the added cost wouldn't be realized in solar payoffs), roof facing due south, etc. Small things now to help optimize solar in the future.

If you are able to change your energy consuming activities to times of excess or overage I wonder just how beneficial that could be over a few years. Examples; make sure you do laundry and dishwasher while your PV is humming. HS

 

[fordmantpw]

If you are able to change your energy consuming activities to times of excess or overage I wonder just how beneficial that could be over a few years. Examples; make sure you do laundry and dishwasher while your PV is humming. HS

Even if you were to do that, your net total usage should be the same (unless you do things like running the dryer at night when less A/C is needed, but that's a completely different discussion). I'm not exactly sure if other places are the same, but the way the net metering agreement works for my co-op is based on a yearly net. If you over produce by x kWH one month, but under produce by x kWH the next month, it equals out. At the end of the year, any extra net that you have gets zeroed out and you start fresh. So overproducing just puts money in the co-op's pocket.

 

[TnAndy]

For anyone considering active trackers, don't do it is my advice. I did the first 3 of my 5 sets of panels on homebuilt trackers when I started in 2007, and panels were $4/watt.

Active trackers are a PITA to keep running....the control units were a perpetual problem (I tried 3 different brands), the linear actuators are good for about 2-3 years and you'll be replacing/rebuilding them, and so on. The parts I built were fine, the poles, the bearing for tilt, etc.....but the support stuff is dadgum nightmare.

Now that panels are a buck/watt and less, there is NO WAY I'd do a tracking system again.....and I didn't. My last 20 panels (5kw) are a fixed, ground mount rack built out of 1 1/2" galvanized pipe with 2" x 3/16's galvanized angle running perpendicular to the pipe for the panel mounting. Not one single issue with it.

SO, save yourself some grief folks....stay away from tracking systems.


My setup (added 10 more panels to the ground mount after this photo). You can see two tracking arrays, the third one is behind one of the others.

View of back on one tracker. Dual axis. Pipe is 8" sch40.

THIS is a WHOLE LOT better way to go:

 

[houstonscott]

For anyone considering active trackers, don't do it is my advice. I did the first 3 of my 5 sets of panels on homebuilt trackers when I started in 2007, and panels were $4/watt. Active trackers are a PITA to keep running....the control units were a perpetual problem (I tried 3 different brands), the linear actuators are good for about 2-3 years and you'll be replacing/rebuilding them, and so on. The parts I built were fine, the poles, the bearing for tilt, etc.....but the support stuff is dadgum nightmare. Now that panels are a buck/watt and less, there is NO WAY I'd do a tracking system again.....and I didn't. My last 20 panels (5kw) are a fixed, ground mount rack built out of 1 1/2" galvanized pipe with 2" x 3/16's galvanized angle running perpendicular to the pipe for the panel mounting. Not one single issue with it. SO, save yourself some grief folks....stay away from tracking systems. My setup (added 10 more panels to the ground mount after this photo). You can see two tracking arrays, the third one is behind one of the others. View of back on one tracker. Dual axis. Pipe is 8" sch40. THIS is a WHOLE LOT better way to go:

Do you have experience with Wattson trackers or allsun trackers. You opinion. HS

 

[MossRoad]

Doubling your money in 8 years means you are getting a return of 9% on your money. There is no SAFE way to do that without risks. What happens when the stock market tanks and you lose 30-40%? Then it looks like a much better investment to go with the known, extremely low risk solar investment.

Its probably a bit lower than 9%. We've been able to double every 7. In 2008 we lost 33% of value of shares in mutual funds. But we didn't sell. We kept buying shares per our plan. It came back to even by 2010 and doubled by 2012. So, it was worth X in 2007 and 2X by 2012 even with the crash of 2008.

Now, had we needed that money to pay bills, then we'd have taken losses. Its probably not a good idea to gamble with they money you need to pay utility bills, mortgages, etc....

 

[fordmantpw]

Its probably a bit lower than 9%. We've been able to double every 7. In 2008 we lost 33% of value of shares in mutual funds. But we didn't sell. We kept buying shares per our plan. It came back to even by 2010 and doubled by 2012. So, it was worth X in 2007 and 2X by 2012 even with the crash of 2008.

Now, had we needed that money to pay bills, then we'd have taken losses. Its probably not a good idea to gamble with they money you need to pay utility bills, mortgages, etc....

Agreed! And investing your money in solar is basically using the money you would need to pay utility bills. That's really where I was going. You can afford to take a bet with retirement money if that is a ways off, but utility bills come every month...

 

[ultrarunner]

We have several solar installs in my neighborhood and one was done 100% by my 80 year old neighbor with a career in the Phone Company.

Every morning it brings a smile to his face seeing how much power generated the day before... guess satisfaction is hard to put a price on.

Also, he did 3 hillside mounted arrays and built the rack so twice a year he can manually adjust the pitch... take no tools and about 10 minutes to do all 3.

He does produce excess power so the gas heater in now electric and the gas dryer is now electric... made the change when the old 20 year stuff needed replacement.

 

[Redneck in training]

What you need to do is shift energy consumption to to electric users. In ex. replace gas water heater with electric, install heat pump to heat/cool your house. Then size the system to provide the required energy.
In example to heat our place would take about estimated 2500-3000 gal of propane/season. At current cost of 1.67/gal the electric heat (geothermal heat pump) beats the propane hands down even without the PV.
Another consideration is direction of the array. It might be beneficial to turn it east or west depending on time of your peak usage. In example your peak consumption or the energy is most expensive afternoon then turning the array west makes sense. You will end up with smaller (cheaper) system while still covering your consumption.

 

[houstonscott]

What you need to do is shift energy consumption to to electric users. In ex. replace gas water heater with electric, install heat pump to heat/cool your house. Then size the system to provide the required energy. In example to heat our place would take about estimated 2500-3000 gal of propane/season. At current cost of 1.67/gal the electric heat (geothermal heat pump) beats the propane hands down even without the PV.

I once read that the cheapest way to supply your electric needs is a single cylinder NG engine generator. Not for everyone but if you are handy and can configure, that it's the cheapest. HS.

 

[TnAndy]

Do you have experience with Wattson trackers or allsun trackers. You opinion. HS

Nope. But I'd bet any of them except the freon based one (no controller/no motors to move the array) will have the same problems.

And when you factor in the cost of panels today, you simply can't justify the cost. I don't think it will EVER payback for the additional power production.

 

[dave1949]

As Ultrarunner and Ladia say, the key to maximizing the return on solar is to displace other fuels that can be more expensive and have fluctuating non-controllable costs.

A lot of my savings come from converting from a LP water heater to electric.

An example:

My solar system produces 4,984 kwh/year. I use all of that on site. At 0.15 per kwh that is worth $748 per year. We have high electric rates in NE.

Part of my solar project was to replace a propane water heater with electric. The propane water heater used about 250 gals. per year. It was not an efficient set-up--indirect fired about 30' away from the boiler. At the current avg. price of propane in Maine of $2.66 per gal. that is worth $665 per year.

Total yearly savings from the solar pv system is $748 + $665 = $1,413

The total turn-key cost of the system and water heater conversion including labor was $19,775.

My un-subsidized payback period is $19,775 / $1,413 = 13.99 years. (Excluding lost opportunity costs.)

The solar system system life should exceed 20 years. I should have "free" electricity for at least 6 years, and possibly more. Newer panels are thought to have a usable life closer to 30 years.

Unsubsidized break even at 14 years and holding electric and propane prices flat at current rates (which won't happen but I have no accurate predictions):
(20 year life) 6 years @ $1,413 = $8,478 + $19,775 = $28,253 total value.
(24 year life) 10 years @ $1,413 = $14,130 + $19,775 = $33,905 total value.
(28 year life) 14 years @ $1,413 = $19,782 + $19,775 = $39,557 total value.

If I invest the $19,775 @ 7% annual return and pay my saved electric and propane bills from that account:
Year
1: $21,159 - $1,413 = $19,746
2: $21,128 - $1,412 = $19,697
3: $21,076 - $1,413 = $19,663
4: $21,040 - $1,413 = $19,627

You can see where this is going, even assuming no increases in the amount saved (due to higher elec. & LP rates over time), and I gave it a one year head start which wouldn't happen in reality. The original $19,775 principle will be decremented during the first earning year when paying electric and propane bills.

 

[TnAndy]

Its probably a bit lower than 9%. We've been able to double every 7.

Then you are averaging 10%.

Rule of 72: Divide your time to double into 72 and you get the rate of return, (72 / 7 = ~10%) or divide 72 by a stated rate of return and you'll get the number of years it takes to double (72 / 8% = 9yrs)

 

[Loren49]

I also remember a Snickers costing $0.35 too. And gas at $0.68/gallon. Ahhh, the good ole days. Oh, and don't forget, mortgage interest was 9, 10, 13% too as opposed to the 2.5-3.5% that we are seeing now. My first home loan 15 years ago was 8.5% (for a 15 year). Our new home is coming in at 3.75% (for a 30 year that we plan to pay off in 15).

Speaking of taxes, to double your money, you have to take taxes into account, which means you need to earn more like 12-13% on your money (unless it is in a ROTH, which you can't just plunk 20k in all at once).

Many will profit in a collapse, but many more will lose, big time. I would call solar a SAFE bet. The BEST bet? No, but a safe one.

You're reminding me of my age.....when I was in my early teens snickers cost a $.05.

A little history
Candy Prices Over The Years

Loren

 

[Loren49]

Electric car benefits? Just myths

This ones for Loren, just to bring you up to date. If you think electric cars are the way to go, don't read this. HS

You should start a new thread for this. A little information on this opinion: I feel some of the claims need supportive references.

Copenhagen Consensus Center | DeSmogBlog
Exclusive: Bjorn Lomborg Think Tank Funder Revealed As Billionaire Republican 'Vulture Capitalist' Paul Singer

A billionaire culture capitalist and major backer of the US Republican Party is a major funder of the think tank of Danish climate science contrarian and fossil fuels advocate Bjorn Lomborg, DeSmogBlog has found.

Not after a GW discussion but kind of interesting you would value a think tank with this GW conclusion.
More global warming will be worse for the economy, says the Copenhagen Consensus Center | Dana Nuccitelli | Environment | The Guardian

PM me if you would like to continue a discussion.

Loren

 

[MossRoad]

What you need to do is shift energy consumption to to electric users. In ex. replace gas water heater with electric, install heat pump to heat/cool your house. Then size the system to provide the required energy.
In example to heat our place would take about estimated 2500-3000 gal of propane/season. At current cost of 1.67/gal the electric heat (geothermal heat pump) beats the propane hands down even without the PV.
Another consideration is direction of the array. It might be beneficial to turn it east or west depending on time of your peak usage. In example your peak consumption or the energy is most expensive afternoon then turning the array west makes sense. You will end up with smaller (cheaper) system while still covering your consumption.

What really needs to be done is ditch oil/gasoline, convert all cars to natural gas and heat homes by burning corn. Its a more efficient use of the BTU's trapped in those fuels VS burning natural gas to heat homes and converting corn to ethanol. Then use solar, wind and water for electricity. I know many frown on hydro power, but I see millions of dollars in wasted energy pouring over the dam in our town that used to be harnessed to generators. Dams are frowned upon because they stop the migration of trout and salmon, which, if anyone is listening, ARE NOT NATIVE TO INDIANA!!! :confused2:

 

[MossRoad]

You folks where solar is practical are lucky. Here we are blessed with the cloud cover that rolls off of Lake Michigan and makes the return on investment much, much longer. Too long to be practical.

 

[SirReal63]

I suppose those of us in Central Texas are blessed, good sun and numerous hydroelectric dams in close proximity feeding us inexpensive electric. No salmon and the trout that there are are in natural flowing rivers.

 

[dave1949]

An interesting way to look at the relative value of energy sources is by using Life Cycle Assessment/Analysis (LCA). These assessments are how it is known if an energy source really is green, or how well it meets some desired goal such as greenhouse gas reduction, and by comparison to other sources.

Google "solar electric life cycle assessment", or "wind turbine life cycle assessment" for renewable examples.

LCA's are very inclusive cradle-to-grave analyses of how much energy goes into producing a solar panel compared to how much energy the panel produces over its service life to compute the Energy Pay Back Time (EPBT). The several studies I've looked at for solar panels came up with 2-5 years for the EPBT on average, some less, some more. The various studies are hard to compare since they are spread out in time and based on different generations of panel technology.

Most of the energy consumed in making crystalline solar panels is due to the high heat process required for purifying the silicon to 99.999%. Newer silicon crystal panels are made with much thinner crystal slices than earlier. Thinner slices mean more panels can be produced from the same silicon purification energy input, which in turn lowers the panel's EPBT.

 

[Redneck in training]

I once read that the cheapest way to supply your electric needs is a single cylinder NG engine generator. Not for everyone but if you are handy and can configure, that it's the cheapest. HS.

The system, if applied correctly, can be very efficient. The waste engine cooling heat can be used to heat hot water or house. But there is limited life of the engine, it requires attention such as oil changes etc. Adding it all together the ROI, despite great efficiency, is not the best. Another issue is noise. And you are still hostage of the fuel supplier.