Solar Panel Question

[manicsubmersion]

There is an individual on YouTube who also has a website and a discussion forum on DIY solar. He has extensive coverage on charging his EV with a separate system not connected to his main house solar system. He is a good source of information if you can get past some of his personal biases and quirks. He also lives in Las Vegas (lots of sun). Search YouTube for the following:

DIY Solar Power with Will Prowse

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[vortix]

A small grid-tied system with net metering should do the trick without breaking the bank. Excess generated during the day will be sent back out to the grid, allowing you to pull from the grid whenever you need to charge your car. No need for expensive battery storage in that case. Should be fairly straightfoward to calculate your annual electricity usage for your EV so you can properly size your system.

 

[MachTee]

A small grid-tied system with net metering should do the trick without breaking the bank. Excess generated during the day will be sent back out to the grid, allowing you to pull from the grid whenever you need to charge your car. No need for expensive battery storage in that case. Should be fairly straightfoward to calculate your annual electricity usage for your EV so you can properly size your system.

Yes, if you live in a 1:1 net metering state. Not all states have such mandate. I think someone posted earlier in this thread that he only gets credited 1/6 of what he pays per kWh in exported excess generation, which is horrible.

 

[bruceski88]

I will have to see once I move in May to another state.. I'm sure will be different. I don't understand the ROI for Gas. I thought solar only powers electricity. The solar Co. only asked for electric bill. Its pretty low since I use gas as well on cooking and water.

Look into mySolarPod, if you want to do it yourself. in most places the system requires no roof penetration.

 

[Hammered]

If you can buy power super off peak, batteries and a grid-tie inverter make far more sense. My super off peak rates are 3.5 cents / kwh OTD, whereas normal rates (as in no special time of use) is closer to 16 cents / kwh OTD (OTD = final cost)

Batteries make far more sense because the system is in operation 100% of the time, whereas solar has a lot of variables.

You can build a 74kWh battery bank for $11k, and if you're using it as suggested which is 80% DoD you get 60kWh usable. That's 1,800kWh of possible load shifting, 100% up-time. The 80% DoD provides a 6,000 cycle point before the battery capacity reaches 80%, meaning in 16 years of continuous use, the battery has 48kWh usable.

For the same cost of the batteries, you can get a solar array that'd make about 50kWh / day on perfect conditions. Lots of clouds / cloudy days = much less output. Plus to take advantage of it you'd need a net metering or sell-back utility agreement. Otherwise you're buying batteries to be able to use the solar throughout the entire day, not just while it's producing.

Another option to look at if you do have attractive super-off-peak rates is a thermal battery -- in that it only stores heat. This device could while in off-peak rates heat up to 200+ degrees (even hotter, but heat changes things unless you want steam) and hold that heat where your hot water system is able to pull heat from it.

For most of the country, hell most of the inhabited planet, people just don't live in an area where solar is viable due to needing clear skies.

 

[ChuckA]

Thanks, is generation same as rental?

Yes but sometimes it’s called a lease with a $1 buyout. In any event it’s tied to the owner of the house for 20-25 years and it’s costly to cancel it.

 

[Scorpy2643]

I did! But for the whole house, not just the car. 34 panels totalling about 15kW. 10 kWh battery whole home backup + solar connected EV charger that pumps any solar overproduction into the car before selling to the grid.

 

[Hammered]

I did! But for the whole house, not just the car. 34 panels totalling about 15kW. 10 kWh battery whole home backup + solar connected EV charger that pumps any solar overproduction into the car before selling to the grid.

Those ground panels are perfect candidates for bifacial!

 

[woody]

Don't know about ROI
Do know about savings:
we are all electric, producing more energy than we consume; 10.695kW array , 30kWh battery backup/critical load panel; electrons for our EVs directly from solar panels(sun)
No fossil fuels for energy*
saving $3,000+/year, more at current HIGH rates. Do not believe utility company or oil companies will lower rates/prices, no matter how many $billions they profit
*Solar was not installed to make a profit (even if the utility company paid a fair amount for production we send them)
yes, savings will be greater than investment, over time

 

[Scorpy2643]

Those ground panels are perfect candidates for bifacial!

You are right! They are indeed bifacial.

 

[VegasWeezy]

Couple of things because I am an engineer. First, the power of a solar system is expressed in units of kW. The energy of an energy storage system is kWh. Your utility charges you for the kWh used. I have a 14 kW (peak) solar array (SoCal) and 40 kWh battery storage - pretty big system for our over 4000 sf house with pool pump and 2 EVs. ROI means Return on Investment and is expressed in terms of % annual return on $$ investment. Pay Back is expressed in Years or Months. As I was taught in school, ROI can be expressed as either a straight cash savings based on initial $$ invested, or as after-tax savings. In the case of solar, the savings is directly related to the bills you no longer pay the utility company and is tax-free, as long as you own the panels. My personal ROI started at 6% Tax Free, but has been increasing the last couple of years because the utility rates that I don't pay have been increasing. I don't care what Pay Back time period is, I do care that almost 8% Tax Free Rate of Return on my investment is pretty darn good and I am very happy. My solar storage takes me through the expensive evening hours and I charge my cars between 10 pm and 4 pm the next day, because that is when the utility rates are lowest. My storage batteries are usually charged up by noon, so the afternoon excess solar generation goes to the grid. I pay $.28 per kWh when I buy it from the grid and the utility pays me $0.04 per kWh when I send excess generation to the grid. Fortunately, I am on Net Energy Metering, so the settlement is supposedly calculated on an annual basis. As long as I generate more kWh each year than I use, my annual settlement is minimal or zero. I am now replacing my gas furnace with a heat pump, so I anticipate a settlement at the end of the year because I am using more kWh, but my gas bill tripled last month, so I still come out ahead with the heat pump.

These numbers for my system are based on paying a solar installation contractor. If you DIY as suggested in one post, your ROI will be much higher (higher is good!) and your Pay Back time will be far shorter.

Here are my NV numbers:

14.8kW system at a cost of $30k

After 30% tax credit (less $9k) and factoring in the interest I will pay (add $4k) on the financing over the life of the loan, my all in cost is $25k.

At the time of purchase, or more accurately, at the go live date my expected payback period was about 11 years.

With energy rates rising as they have over the last 6 months (going from $0.13 to $0.16), my payback period has dropped to 8.5 years.

As far as ROI, using the expected degradation curve for the panels and holding the energy cost steady at $0.16 for 25 years, my ROI after 25 years would be $45k. This would equate to roughly 4.2% tax free annual ROI.

Of course that assumes I use the system for 25 years and the energy rates remain constant.

 

[woody]

My old school definition of ROI is: divide profit earned on investment by cost of investment. 7% (or greater)/year was /is considered good. 7%/yr meant doubling your original investment in ten years. 10%/year meant doubling your investment in seven years, etc. The same percentages applied to business success. These figures have served me well over the years (only time I did better was circa 1980 when the banks paid 12.5%, very short lived).
The only way I see of any real ROI on solar is if the utility company would actually pay for the electrons I sell them. I do not see that as a probability.
I am saving, and anticipate saving more in the future. And the tax free part is definitely a plus. I have never considered savings to be profit.

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