Jamie in Chile wrote: ↑Fri Feb 01, 2019 4:59 pm
At my latitude there is still a decent amount of solar power in the winter. I might have still got say 70% of my needs maybe in winter and just had to top up the difference with grid.
That's not too bad. There are some locations like that which get quite a bit of sun most of the year.
That 30% loss for half the year is unfortunate, though.
Jamie in Chile wrote: ↑Fri Feb 01, 2019 4:59 pmEven in cold countries, there is still plenty of industrial and office activity in the afternoon so it's not that bad.
Not necessarily more activity than in the morning, though. And modern factories run pretty much 24/7 to take advantage of the infrastructure. Only retail and office stuff is closed at night, when that power usage gets distributed to homes. Those aren't the big power users, and very likely demand is higher when it's decentralized to homes plus cooking etc. so it might be higher in the morning and late evening.
Jamie in Chile wrote: ↑Fri Feb 01, 2019 4:59 pmBatteries cost about $400 dollars per kilowatt hour (kWh) to $750/kWh typically. I could have got 2 1.2kWH energy storage units (batteries) so total 2.4kWH for a bit over $1000 including installation and an inverter and other needed components. However, I wouldn't have been able to use the whole 2.4kWH because you can't let the batteries discharge all the way to zero repeatedly, it is bad for the battery. But you have still got 1.2-2kWH depending on how far you are willing to drain the battery.
That's pretty expensive, and that's not a lot of power. They also don't last forever, like you said, so you have to account for that.
Jamie in Chile wrote: ↑Fri Feb 01, 2019 4:59 pmWe used an average 8kWH per 24 hours that's 0.3kW/hour. In the evening period it's probably more like 0.5-1kW/hour. We would have had enough to keep the solar power going for a couple of hours after the sun down to power everything from the fridge to the TV. And in summer, that would have got us to bed time or very close.
Your refrigerator doesn't shut down at night. At least I hope it doesn't. In order to keep the safe temperature at night and in the morning you'd have to get it *very* cold in the afternoon (negative something), and that could damage your food from freezing.
Maybe a technical solution would be practical like using some kind of fluid that freezes and melts at the temperature you want to refrigerate at (around 1.6 degrees Celsius), thus absorbing some heat when the temperature rises above that in order to melt. Or just a *huge* amount of insulation and thermal mass... or some kind of coolant body you cool below freezing, then use a pump to circulate it into the fridge as needed.
I'm just not sure any fridges like that exist, and that might not be an easy build... particularly considering the stakes (improperly refrigerated food could be dangerous, so you'd need a digital thermometer to make sure it didn't go too high for too long, and you risk wasting a lot of food).
I could see solar becoming more viable if we had that kind of energy demand flexible infrastructure in place, including heating water during peak production, but that seems really far off right now and a much bigger ask than people installing panels and batteries and just going on with business as usual.
Jamie in Chile wrote: ↑Fri Feb 01, 2019 4:59 pmYou can use batteries to store solar. However the battery systems are not as cost effective as a system that sells to the grid in the afternoon and buys after dark.
I can see that being more cost effective, but as I said that just commits us even more to fossil fuels. Fossil fuels are the only thing that can be reliably started up at night and shut down during the day. Nuclear takes a long time to adapt, so it's good for base load but works poorly with solar. It kind of makes them natural enemies. They can work together a bit with solar taking the extra afternoon load from air conditioning, but I think that's about the extent we should expect of solar. We really need to use nuclear to carry the bulk of power generation.
Jamie in Chile wrote: ↑Fri Feb 01, 2019 4:59 pmHowever thinking of safety, solar panels are good in normal power cuts (and they are frequent here), as well as disasters (earthquakes here can take the power out for days, but that is a week every 5 years) and that was one of the reasons we wanted to get it (we have power cuts of minutes or hours all the time).
That makes a lot of sense. Better some power for part of the day than none.
Jamie in Chile wrote: ↑Fri Feb 01, 2019 4:59 pmSolar panels are also potentially good for an end of the world scenario. So they are actually a safety net. If civilization has gone, and the electricity grid is gone, you still have electricity. Also, if money has become worth less or even worthless, you still have something of value.
Assuming you have somebody to repair them.
Although if solar is making a nuclear grid less likely, promoting it may make the end of the world *more* likely rather than less.
Jamie in Chile wrote: ↑Fri Feb 01, 2019 4:59 pmI believe we should have a mix of different renewable including solar, wind, and water pumped up hillsides ready for release (this is on demand clean energy).
Water pumping is good, but not everywhere is lucky enough to have the geography to make that plausible.
Jamie in Chile wrote: ↑Fri Feb 01, 2019 4:59 pmI also think as we transition to renewables we should increase the total capacity a bit and connect pipelines to other countries so we can buy/sell when one has high supply and the other low or vice versa.
Transmission losses long distance are a pretty big problem, as is that kind of infrastructre cost.