Solar production. Panel ratings/claim vs reality

[Grumpycat]

I just read that in part of the Netherlands, the power company is paying homes with solar power to NOT produce power at certain times because the solar power is disrupting the grid in some areas. They have too many solar panels in some regions so PV can produce more power than can be used.

Quite possible in peak sun hours. Is begging for a means of centrally throttling grid feed.

I am late to this discussion and the OP seems to have made the correct design decisions. Years ago I took a solar power class and I learned a few things:
- A rough estimate is that 77% of the power produced by the panels will make it to the power outlets. I wonder if this is still true due to more efficient invertors.

This one claims 96.5% to 99.9% efficiency:

Fortress Power Envy 12kW - Fortress Power

The Fortress Power Envy 48v Inverter is available in 12k, 10k and 8k models.

www.fortresspower.com

- Many people think that solar panels will provide power during a power outage, but they don't realized without battery storage, the solar panels will be disconnected from the grid. and thus one won't get power.

A grid tie inverter requires a pilot signal to sync it's generation. Is AC, can't just parallel DC batteries. The Tesla Powerwall 2 is able to provide that signal keeping grid tie inverters online.

The hot thing today is hybrid inverters such as the Fortress Envy listed above and the Tesla Powerwall 3 which manages PV panels and batteries in one unit. Happily runs off-grid.

- It was better, at least in NC and I suspect in other states, to produce slightly less power than one uses to avoid "selling" power to the power company. Regulations to sell power to the grid change and can be a PITA to follow. It is just better to produce slightly less power than needed and not worry with selling to the grid. Or if one is going to over produce power, except that one is giving money to the power company.

Is a matter of how difficult the paperwork. Is better to sell power for 2.5¢/kWh rather than throw it away.

The price of LiFePo batteries has really fallen over the last few years which makes having battery storage more reasonable.

Yes, the LiFePO4 cells are safer, accept 100% charge without excessive wear, but weigh more than lithium-ion. The weight makes almost no difference for home storage.

When the inverter panels showed up I thought they were a good idea since they lower wiring cost but I have heard that some brands have had failures of the inverters but I think I would rather have inverters off the hot roof in an easily accessible place. Today, I think I would use Victron equipment for the invertors, battery chargers, batteries, etc. Though, Tesla's power wall is certainly interesting.

Microinverters? One on each panel such as Enphase features? The cost is greater but has the ability to optimize each panel's production. And networked so as to monitor each panel individually. If one is partially covered it affects production of all panels in a string using a larger conventional inverter.

Some have come up with optimizers mounted on each panel yet still using the central inverter. SolarEdge uses optimizers on each panel costing less than Enphase, but then a large but simpler inverter for DC to AC conversion.

PV inverters must optimize the line voltage for maximized power production. PV panels need their output voltage optimized for solar brightness and temperature.

 

[ultrarunner]

I've seen a grid tied inverter that has one outlet powered even when grid goes down and sun is out...

I like the idea and it showed a small refrigerator plugged in and a laptop.

 

[Grumpycat]

I've seen a grid tied inverter that has one outlet powered even when grid goes down and sun is out...

I like the idea and it showed a small refrigerator plugged in and a laptop.

Yes, I've seen that model. The 120V AC outlet was limited in power but it was able to run something relatively small without the grid or a battery.

 

[newbury]

Has some calamity hit the fan that I missed?
I was on this thread about a month ago and about the same time I looked at ebay on panel costs. At that time panel costs looked slightly below what I paid for 1 a year ago. ~$60 for 100 watt.
Today I look and see:

400 Watts Solar Panel Kit 100A 12V Battery Charger w/ Controller Caravan Boat RV $26 w/ free shipping

linky

I was just looking to hook up a panel or two of 100watt panels for shade and charging batteries for an occasional use micro fridge and a light. 400 watts would let me add my laptop and Mobley.

 

[ponytug]

Has some calamity hit the fan that I missed?
I was on this thread about a month ago and about the same time I looked at ebay on panel costs. At that time panel costs looked slightly below what I paid for 1 a year ago. ~$60 for 100 watt.
Today I look and see:

linky

I was just looking to hook up a panel or two of 100watt panels for shade and charging batteries for an occasional use micro fridge and a light. 400 watts would let me add my laptop and Mobley.

Buyer beware!

Be careful with the claimed specifications. Oftentimes I find something like a 6x12" panel comes with an impossibly high 100W rating.

Used prices are variable, but new prices are still pretty much where they were a year ago, generally a little higher.

All the best,

Peter

 

[sd455dan]

Has some calamity hit the fan that I missed?
I was on this thread about a month ago and about the same time I looked at ebay on panel costs. At that time panel costs looked slightly below what I paid for 1 a year ago. ~$60 for 100 watt.
Today I look and see:

linky

I was just looking to hook up a panel or two of 100watt panels for shade and charging batteries for an occasional use micro fridge and a light. 400 watts would let me add my laptop and Mobley.

this was also posted recently
effective as of August 1, 2024: Under the Sec. 201 tariffs, all imported solar cells and panels (regardless of country of origin, except for a few minor exceptions) are currently tariff Free for the first 12.5 GW of solar cells imported. After that that the tariff is 14.25%

SEIA Statement on President Biden Action to Support U.S. Manufacturers by Raising Section 201 Tariff Rate Quote on Imported Solar Cells – SEIA

The Solar Energy Industries Association (SEIA) is leading the transformation to a clean energy economy. Learn more at seia.org

seia.org

 

[newbury]

this was also posted recently
effective as of August 1, 2024: Under the Sec. 201 tariffs, all imported solar cells and panels (regardless of country of origin, except for a few minor exceptions) are currently tariff Free for the first 12.5 GW of solar cells imported. After that that the tariff is 14.25%

SEIA Statement on President Biden Action to Support U.S. Manufacturers by Raising Section 201 Tariff Rate Quote on Imported Solar Cells – SEIA

The Solar Energy Industries Association (SEIA) is leading the transformation to a clean energy economy. Learn more at seia.org

seia.org

THANKS!
That may explain part of the drastic drop in price. I had been looking at spending ~$200 for 4 panels with nothing else, now it seems the bottom line price may be nearer $30.

 

[dmccarty]

Is a matter of how difficult the paperwork. Is better to sell power for 2.5¢/kWh rather than throw it away.

There were at least two problems, the paperwork and the rules were changing. So what was true today was not true tomorrow. If one over produced you did not 2.5 cent per KWH. You got nothing. You just gave the power company free power.

The rules have changed since then and I don't know what they are today in regards to how they pay for power. Getting a state refund for a solar install has also changed.

 

[sd455dan]

THANKS!
That may explain part of the drastic drop in price. I had been looking at spending ~$200 for 4 panels with nothing else, now it seems the bottom line price may be nearer $30.

I ordered a pallet of panels a while back and the price today from that supplier is exactly the same it was before the announcement so not really sure what is going on. the company I bought from put out a video that says almost the opposite thing is likely in the near future as the 201 statement. Maybe they crossed in the mail. It does look like the prices are not going up so far.

 

[newbury]

Yea, I jumped for joy to soon.
Now I don't trust the prices I saw.