Powering one’s house is not a smart way to deploy solar, mainly because people aren’t IN their houses most of the time. That’s why most home solar systems are grid-feed configurations (like Dr Jellyfish’s parents). Solar heating makes a lot of sense (because hot water is easily stored), but not PV.
But yeah, solar is dirt cheap. It’s in the interests of TPTB to perpetuate the myth that it’s outrageously expensive. PV panels are now about US$1.3 per installed watt, depending on technology, including the cost of metal mounts and MPPT electronics, but not including storage (which, obviously, is highly variable depending on how much is installed). In a moderately sunny climate - anywhere south of the UK - you get about 2.5watts/day for each installed watt. Near the equator, twice that. So if you wanted to average 4kWh day of electricity - which is more than enough for a modern household - you’d need to install about 1.6kW of panel area, which would cost US$2100.
So, where does the rest of the money go when you pay 10,000 for a 1kW solar array on your roof? Well, it goes into the pockets of the installation contractors, who have a nightmare job trying to install solar panels into a building that was never designed for them ... and who, incidentally, are having an awesome time selling third-rate kit to uneducated homeowners who have [i]no idea[/i] of the wholesale prices. And to the taxman, who skims 20-30%. If the panels were integrated into the building design, the installation cost would be a few hundred US.
Because it’s being wasted. Energy output is like roads, or computer memory space - the application fills whatever space is available. A lot of that energy expenditure is being pissed down the toilet by third-world countries adopting 19th-century technology, in the mistaken belief that that’s the route to “development”. China is finding out - too late - that it doesn’t quite work like that.
The key to all this is to stop the waste, and to do that we need to think like this:
“This fixed number here, X, represents the amount of land area and resources we would like to devote to energy generation. It delivers an amount of energy Y, per person, that is also fixed. Given that constraint, how do we get all the things we want from it?”.
It’s hard to get politicians or industrialists to think that way because their natural instinct is more,more,more. There’s no why. More is good. It’s axiomatic. But constrain must happen, one way or another: if society can’t do it softly, nature will do it with lethal force.