Having a new off-grid property, I've been investigating solar energy. It's a fact that PV prices have tumbled in the past 3-6 years. Each year I would check it, the PV pricing became more attractive. However, they have a long, long, long, long, long way to go before it will be more than a passing effort.
The things I've learned in the past month about solar make me laugh pretty hard when I hear someone say it's going to be a preferred anything in the future. Since I cannot attach anything, here's a snippet of my calcs for off grid:
Load Watts time in hours example 15 minutes = .25 hours watt hours Concurrent use in watts
Lights 24 4 96 48
TV 100 4 400 100
Computer 40 2 80
Well pump Use daily average run time(*wind *) 0 0 0
Microwave(*none*) 0
toaster(*propane on stove*) 0
refrigeration (*propane*) 0
Freezer (*propane*) 0
coffee maker(*percolater*) 0
Washing machine, One cycle per two day 700 0.6 420
Vacuum(* or washer, either but not both*) 1200 0.5 600 1200
Power tools(*hard to calc daily use!*) 250 0.12 30
Total daily load (Watt hours) 1626
Inverter efficiency (use midpoint on efficiency curve) ex 80% enter .8 0.8
Total daily load (Watt hours including inverter losses) 2032.5
Maximum load (to inverter) 1348
Lowest daily insolation for area and time of year the system will be used 2.4
Use PV watts to determine insolation or
http://www.gaisma.com/en/
Amp hour capacity Max charge current FLA Max charge current AGM
Battery bank @12 V (AH 20% daily DOD) 846.88 105.86 211.72
Battery bank @24 V (AH 20% daily DOD) 423.44 52.93 105.86
Battery bank@48V (AH 20% daily DOD) 211.72 26.46 52.93
Amp @12V Amp @24V Amp@48V
Panel wattage required PWM controller 1693.75 141.1 70.6 35.3
Panel wattage required MPPT controller 1270.31 105.86 52.93 26.46
Maximum amps to inverter @12V 112.3
Maximum amps to inverter @24V 56.2
Maximum amps to inverter @48V 28.1
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Presuming that the average person in the US consumes about 15MEGAWatts per year, making enough power for us via solar will require that every square inch of non-populated states of Texas, NM, OK, and most of AZ have to be covered in PV to power the nation. I think those states might object to that, but - I could be wrong.