The amount of solar energy falling on the surface of the earth is staggering. in raw numbers more solar energy falls over the hemisphere facing the Sun in one second than all the energy humanity has used EVER since we started burning wood in camp fires as cave men.
The amount of energy is measured in exojoules. Put another way every square meter of surface area at the top of the atmosphere gets over 1400 watts per second over 2 horsepower for every square meter everywhere on half of the surface area of the planet.
capturing 20% of this would require a surface area ruffy equal to Texas to power the entire USA energy needs Texas is less than 1% of the surface area of the planet. The problem is not lack of solar flux of energy it is turning that into something that can be stored or transported economically from where the sun is to where people need to use it.
The break point in sunny area’s is about $1/wh installed capacity. At that price going off the grid becomes a real choice. I’m about to buy 10 acres and build a completely off the grid compound using thin film cells if these guys can get the price down all the better. the all in cost currently for a solar/ wind off the grid is $.20/kWhr we pay .13 for grid power here I’m planning on using a listeriod diesel as back gen, diesel is $.40 kwhr @ $2.30gal diesel & 25% efficiency tank to plug, not counting depreciation on the genny or O&M costs.
In Texas solar makes economic sense when far enough off the cities to have to pay for a grid tie in at $1.50/wh or less. no subsidies needed at those prices.
There is an issue with thin film cells in hot climates, the performance will degrade due to the excess temps adhered to the roof or wherever. Panels ventilate better due to the air space behind and don’t overheat as much so the performance doesn’t degrade as badly in high temp conditions. Cost benefit of thin film may outweigh this for you but it should be accounted for in sizing your array.
Also look into multilane ductless mini-split heat pump for AC and heat, they’re very conducive to solar. Be very careful about managing the condensate, though. They throw off a lot of water in climates that are even remotely humid.