so at 120 volts that is 54.75 kw !!!! it’s a ohms law thing.
or $10.95 worth of juice,,,, a day.
with About a FIFTY year payback and decades of free power to follow.

and hence the problem nobody is doing the real math
you can’t run a 120 volt 100watt any thing with a 100w 12 volt panel.

but you could run a 10 watt 120 volt night light for how ever many hours of light.
BUT WAIT it gets worse
-10% for the inverter
& -20% for charging of the batterys

so realy you could only run a 7 watt 120 volt night light, with your $500 panel
not smart or green

$500 panel, installed @$2 per watt (where the industry is headed) = 250 watts.

Placed in a location with 6 hour average solar day = 1.5 kW per day, 547.5 kW per year.

At $0.20 per kWh that works out to $109.50 per year. About a five year payback and decades of free power to follow.

Current costs should not be used as a marker for where costs will be in a few more years. Unfortunately we have to invest more for today’s panels in order to provide capital and incentive for tomorrow’s panels to appear.

Panel manufacturing cost have already broken the $1 per watt threshold and improvements in installation are happening.

There are no batteries involved in grid solar. And most installations do not use active trackers. As solar prices continue to drop it’s cheaper to install more panels than to install trackers. (Trackers only pay if you’re closer to the equator, even at $5 a watt.)

Solar produces when demand is highest – during the day. The power produced gets sucked right up and used.

Having solar on the daytime grid means that it won’t be necessary to build extra expensive 24/365 plants that will not be useful during off peak hours.

If the solar panels exceed needs demand then expensive to fuel natural gas turbines can be turned off and/or hydro facilities can be shut down, saving the water for when the sun isn’t shining.

And, remember, nighttime winds are often stronger than daytime winds. Solar and wind tend to produce at different times of day. Southern CA solar is going to work nicely with Wyoming wind which tends to start up right before sundown, PST. Move the power back and forth on the existing Intermountain Interie, the HVDC line that stretches from SoCal to Utah and is in process of being extended further north.

Solar prices are going to continue to fall. Because solar can be distributed to rooftops and over parking lots the cost of transmission is eliminated. Maintenance is low, lifetimes are long.

The final grid solution will almost certainly include a vast array of generation technologies (wind, solar, concentrated thermal solar, geothermal, tidal, hydro, etc.) along with a variety of storage solutions (pump-up hydro, industrial scale batteries, flywheels, CAES) to create a grid that supplies power when we want it.

I get the argument about solar, but the energy doesn’t necessarily have to come from solar, water turbines are hugely effective, and there is always wind turbines, which you can actually construct yourself in a easily. Ideal for modest systems, esp in the boondocks.

Here in South Africa we have suffered huge electricity shortages, and our the only incentive our electricity provider is offering rebates on solar geysers that are proving to be very popular, but the cheap ones everybody are installing aren’t covered by the rebates :-(

Many computer users have ink jet printers. You can get one for $100 US. In 5 years the ink costs are at least triple that. A solar system is like buying an ink jet printer and never having to buy ink.

Policy makers, investors, and energy users must think about energy decisions that are way out past our fingertips.