Estimated cost to put a 4k system on my roof including the 30% tax credit is $8500. At my current average SCE bill of $50 that means a raw break even point of 14 years. Factor in the present value and opportunity cost it does not make economic sense for me even with high sunbelt insolation and high energy costs of $0.19/kwh.

There are lots of other good reasons to consider solar PV including energy independence, the ability to generate electricity even when the grid is down, or simply wanting to do your part to help phase out coal generation. From a pure desire to save money long term, you probably need to be in the sun belt with Edison rates above $0.10kwh and have an electric bill above $200/mo.

Same with me. It would be a money loser for me with my low energy costs. I spent my money on making the home more efficient with a payback of only a couple of years.

When I built our home, I tried to make it energy efficient as I could with R30 ceiling and floor, plus R19 in the six inch walls, etc., etc.. The fact that even the lowest level on our tiered rate system by the power company is up to $.29 per kWh up to a monthly usage of only 520 kWh/month (down from 620 kWh/month) made it a good move to make. If I remember correctly, that rate was $.19 per kWh not more than ten years ago, which made installing solar made sense. At the rate they're making increases, no telling what it will be even in the short term.

Not sure who you are with. PG&E wants you to bend over and go in dry.

https://calmatters.org/economy/2019/08/pges-rate-increases-what-you-need-to-know/


How much more will customers’ costs go up?
Based on what we know, the average residential PG&E customer could pay nearly $360 more a year in three years, or a 17% increase in their monthly bills. This is because the utility is asking permission from state and federal regulators — separately from the bankruptcy proceedings — to increase its revenue in five ways. Most, but not all, of the new revenue would be passed to consumers.

First, PG&E has asked for a three-year increase totaling $2 billion.That would include a 12.4% jump next year, a 4.7% increase the year after that and a 4.8% hike in 2022. That’s nearly a 22% rise. PG&E says much of the extra money is needed for fire-safety improvements such as more fire-resistant poles, covered power lines, new weather stations and high-definition field cameras.

In this scenario, for the average PG&E residential customer using both electricity and gas, the current bill of $172.94 a month would go up to $193.25 in three years.

I have SDG&E, and they probably have PG&E beat in terms of raising rates (note the rates I've stated before). In my area, they are installing steel poles along with much larger steel poles that seem to be the ones carrying larger distribution lines. We're all glad to see this even though they are ugly as hell (not that the regular poles are beautiful) and won't improve the availability of insurance, which I and most people around me have had not renewed and had to go onto the CA Fair Plan at a third and more increase in premiums for less coverage. Those PG&E rate increases sound bad, but I have the impression SDG&E had them beat a long time ago.

From the same article.

But PG&E isn’t alone. While Southern California Edison rates largely appear to keep track with inflation at 18%, San Diego Gas & Electric’s have jumped 51% in the past decade. That’s partly because SDG&E’s customers have been installing solar panels at a higher rate, which distorts the average cost because each customer appears to be consuming less electricity.

Interesting. I can tell you I called the solar telephone line for SDG&E once and the lady was none too friendly. It's probably the same in other sunny places but lots of large businesses, factories, school parking lots, and more are covered with solar panels all over the place.

Using that link and the defaults I can generate $348 worth of juice a year. :eek:

Or gain of opportunity...if you run those same numbers looking at the S&P in 2006 and the years following, I'm sure the numbers don't work out nearly as well. While I agree with your point, I've learned that trying to time or predict the stock market has a much MUCH less success rate than trying to predict what will happen to utility rates! Locking in a solid ROI that only seems to get better every year they raise rates vs. what could potentially happen with the S&P over the next 5-7 years was worth the risk to me.

There is risk involved. And the last couple of years the rate of return has been really good. It is still a parameter that must be taken into account. Is areas with very high electricity rates and high solar energy potential it can save money. In many other areas it is a money loser.

For me it is a money loser without even considering the potential lost investment gains.

In much of Cali you would be foolish to not go that route due to the excessively high costs. And those costs are only going to up with increased home solar production. The fixed costs of PG&E and others isn't going to go down. They will still have the same amount of transmission lines to monitor and repair. They will still have the number or powerplants to supply round the clock power. That fixed cost will just be spread out over fewer customers at an even greater future cost.

The upper middle class and above have the resources to add the solar panels. The lower middle class and below will take it in the shorts because they don't have 10 grand sitting around to use on an upgrade. . Same with fuel prices and EV sales and Cali dislike for the entire O&G sector.

He said he hasn't paid a utility bill since the installation of the system. If he hadn't installed the system and put $18,900 into the market he would have had to come up with a utility payment every month. Putting $18,900 into a stock portfolio and then taking between $595 and $225 back out every month would change the calculations significantly.

It is still part of the equation that shouldn't be overlooked. In my case I would have to spend 20 grand or more to save 150 a month.

Some areas are well worth the investment. In others it is a money loser. Just look at all parameters to determine cost effectiveness.

Not to mention the tax implications, dividend management, maintenance of panels...and then my head starts to hurt and I give up trying:)

No kidding, bio.

Exactly...it's a no brainer to do it in California, and a no brainer not to do it in Ohio (based on ~$.02/kwh)

It's the in betweens that really have to look at the equations closely.

what maintenance of panels??


BTW, I looked at this 3 times, and am told to wait until I need a new roof

Cleaning, but you can do that yourself. Over the 20 year lifespan you should expect some system component replacement/repair.

I thought in a thread a couple weeks ago we established that without a battery system, code is that the solar provides no energy when the grid is down, to prevent backfeed and electrocuting the poor guy trying to get the power back on.

I would be surprised if there is not an available auto disconnect.

the panels (herabouts) are guaranteed good for 20 years, and so is the output

cleaning might help a tad

I hope my downhill neighbor does not clean his - when new the glare was terrible - right to my deck

another issue is squirrels getting to the wires and chewing on them - so make sure the install uses a barrier like heavy hog wire, etc.

I get $481 annually. I assume this -> non-economic?

True. If you want complete energy independence or the ability to generate energy while the grid is down, you need to factor in enough lithium batteries to cover your needs. With this setup, a relay disconnects you from the grid in a power outage and runs on solar and battery alone. When the grid comes back up the relay energizes and reconnects you to the grid.

I also have 23 micro inverters and while they should be very reliable, things do happen.

Just got my bill. $46.96 for a 2600 s/f home. Highest I have had all year was Aug at $151.12. Taxes included. 15 year old heat pump with gas backup on heat.

It is an interesting thought experiment. Since panels are estimated to produce significant output for 20 years we can make some comparisons.

If we invested $20k in the S&P 500 in 1999 it went through 9/11, 2 bull markets, 2 bear markets, and the greatest recession of our lifetime. Today that investment would be worth $62k.

If we invested $20k in solar PV in 1999 and our elect bills were $3000/yr, we would have saved $60k in bills or roughly even money. We just paid 20 years of elect. cost in advance. We know that rate increases were stiff in CA during that period, the savings probably would have been greater. Lighting and appliances are also far more efficient now so that would have some moderating effect on the rate increases by using less kwh per household.

you'd invest the monthly savings from the PV panels in an S&P Index fund, so figure that in too...

but wait!! there's more!

over the 20 yr period, there is a P() of new, improved output PV panels coming on the market, so...



Thx to Ron Popeil...

Good one Webb!

By dollar cost averaging $250/mo electricity savings into the S&P 500 over 20 years instead of investing $20k lump sum in 1999, you moderate the downturns and maximize the increases. As a result your investment would be worth $166k today. A 9% return rather than a 6% return. By spending $20k on solar and investing the monthly savings you net $100k over a $20k lump sum investment in 1999 in this simplified example.

https://dqydj.com/sp-500-periodic-reinvestment-calculator-dividends/

I average 42Kwh per day. I'm trying to figure out that line from RB. I found a site that gives a calculation for sizing and it appears I need a 15kw system to satisfy my electrical needs. From a quick search that a $17,000 system :eek::eek:

That seems terrible on first glance but if there's a 30% tax credit that drops the cost to 12,900 which would make payback a little less than 7 years. Might be worth a look. Only thing is, I'd probably use my heat pump more in the winter but if the calculator is right, based on a 15Kw system, standard module, fixed roof type, 14.08 system loss, 20 degree tilt and 180 azimuth I'd produce about 19465kWh per year which is about 3000kWh more than my current usage. I should have some wiggle room for increased consumption.

That actually sounds on the low side.

Prior to tax credit 2019

http://forums.pelicanparts.com/uploa...1576330442.png

This is a 15kw kit for $22,575. Installation not included.




https://www.gogreensolar.com/products/15080-watt-15kw-diy-solar-install-kit-w-solaredge-inverter

HOW MUCH SHOULD I PAY A CONTRACTOR TO INSTALL THE SOLAR KIT?
Any licensed general, electrical or solar contractor can install our solar kits. If you select to hire a contractor to install your solar kit, you should expect to pay approximately $1.00 per watt for labor, wire, conduit, fittings, breakers and other miscellaneous electrical components to complete the solar system installation. For a 10 kW (kilowatt) system, which is 10,000 watts, you can expect to pay $10,000 for installation. If needed, we can assist you with finding a contractor.

Here's the one I looked at
https://www.gogreensolar.com/products/copy-of-15-080-watt-15kw-diy-solar-panel-kit-w-string-inverter

Have to look into the string vs solar edge inverters. The array would fit on the south facing roof of my barn. I think I could handle the install since I've done the main service lines for several homes.

Delphos Ohio, using PV Watts, says you will get about 4.57 kWh per kW installed.

42kWh/day divided by 4.57 = 9.2kW to equal your usage. I would suggest rounding it to a 10 kW system.

Depending on your location and codes, you may need a licensed electrician to install. You will also generally need to work with your electric company and generally need to submit a modified one-line diagram for approval. They also usually want to inspect your system before you turn it on.

The issue with roof mounted solar is to insure you are tying into the rafters and not the decking. And that you are sealing the penetrations properly to prevent leaks. And finally, that you have the system setup to allow for thermal expansion/contraction.

If you have a lot of trees which might shade part of the system, you may want to use micro-inverters which adjust output of each panel individually. The other alternative is a central string inverter with "Optimizers", which is what Solar Edge does.

If your roof is clear of trees, then a straight 600V string inverter is fine and the least expensive way for grid-tied solar. Remember, this type of system will not operate when the power is out. And if you have a generator, the connection MUST be on the utility side of the transfer switch.

If you want a system that works when the utility is out, you will need a battery based system. These use "Charge Controllers" and feed the battery directly. Some do allow you to sell excess power to the utility.

As far as the Tax credit is concerned, you need to have it OPERATIONAL by Dec 31st, 2019 to get the 30% credit. Next year, the Federal Tax credit drops to 20%.

There is a bill in Congress to extend the Tax Credit. But Congress is "distracted" at the moment.

Around here a 10kW system will be about $25K

That is about what they are up my way.

As mentioned the NREL site says I can generate $481 of electricity annually with rooftop PV.

I found another site, which exposes the details a little more. Below is a screenshot of the result I got. This is with manually specifying as many panels as will physically fit on the roof. The site's default output had fewer panels.

http://forums.pelicanparts.com/uploa...1576340349.png

Does this mean that I simply can't use solar to generate all my home electricity, unless I can cut consumption by 50%? It looks like my house simply doesn't have the right roof area to interior volume ratio, plus I live in the rainy side of Oregon.

I don't know if James' 4.57 kWh per kW installed is a yearly average for your latitude. He's a sharp guy, so he probably took that into consideration. I also don't know if your average of 42 kWh per day is taking into consideration the fluctuation between seasons of high generation and low. Like I said, my 7.75 kW system generates a high of maybe 52 kWh per day during the high generation season and about half that during the low season.

Your rates are just staggering. Your system in my area (sw Okla) would save me a thousand a year. On your place it looks like 3 grand or more.

Anything is possible but because insolation in your area is 1/2 that of SoCal, you would need 2x the panels to generate the same output as Marv. You would probably need to mount them off the house in an ideal location to make the most of your sun exposure. This might be a $50k project so you have to decide if it makes sense.

Yes, like I said I probably have about three more years to break even. And as I said before, the impetus for going for it was my bill going from $495 (all electric house) the highest month to $595 the next year, which showed to me the amount they raised rates over that past year. Rates are so high, the County (City?) is considering establishing an alternate system to compete with SDG&E and offer up some choice for customers. Truthfully one of the major satisfactions is knowing I'm sticking it to the utility company even if it were possible to use the money in a better way investment wise. My conservative estimate at the time was over $3K+/yr. and it's higher now.