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Comment by KptMarchewa | Hacker News Reader

We've solved energy in middle of sunny, summer day. We haven't solved it in middle of winter night.

We're in the process, and may arguably already have, for the tropics.

Get more panels, maybe some batteries.

Winter being a problem really depends on location. Seasonal variability is much lower near the equator. Also batteries are becoming a solved tech. Also wind is anti correlated with solar, it's stronger in winter and at night. So you want 50-50 to minimize the need for storage.

Luckily most people are sleeping in the middle of the night, so electricity usage is already quite low. That's why many areas already have a separate discounted Night Tariff.

Additionally, the winter might not have a lot of sun, but it usually does have quite a bit of wind. Build a combination of solar and wind power, and you've solved the biggest issue. The rest can be picked up by hydro and gas peaker plants (short-term), or battery storage and other new technologies (long-term).

the winter has plenty of sun and few clouds.

Irradiance of a surface is lower at the same time of day (think of shining a flashlight perpendicular to the ground vs at an angle) and the number of hours the sun is above the horizon is also less. Lower power at any given time of day and for fewer hours of the day.

Here’s a figure to demonstrate that:

https://www.researchgate.net/figure/Monthly-output-from-sola...

Any basic irradiance analysis of a surface in any day lighting simulation software will clearly demonstrate this.

Additionally, in winter, the peak energy usage will often be well past sunset in many locations around the world (and it will get even more pronounced with heating electrification). This is why batteries+wind will be very important.

I was very surprised the difference is that small. Intuition would suggest there to be a lot of sun in the summer given how hot it gets.

The day is roughly half as long but you get 40-50% per month ???

Really a lot more than I imagined.

Not sure if that involves changing the angle.(which would complicate things)

It isn't a popular or sensible technology atm but sterling or other heat engines do work and they work even better if there is a cold source. There are experiments with heating water with solar voltaic. I read they are reaching 70% energy conversion.

It seems there is lots of room for further tinkering. 40% isn't bad tho

It depends where. In Poland, we had whole 7 hours of sun this December.

in antarctica you may need nuclear or ammonia storage or something, but the rest of us can just use batteries

If you can reduce even 50% of the consumption from the grid that would be huge.

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