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Comment by tomohawk | Hacker News Reader

For solar and other intermittent sources to be viable at scale, a continental long haul grid is needed, as well as a way to store power. Generally, you need 2x intermittent capacity to replace non-intermittent, as you need to be able to provide power, and store power at the same time.

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The grid doesn't rely on a single source of generation at scale today, I don't see why doing solar at scale is any different. A big chunk of power usage follows the sun; you don't need to store anything until solar is more than that portion.

There's this little thing called the sun, and it doesn't shine a big chunk of the day. Right about when you need the most energy for heating and lighting.

Electricity usage generally peaks during daylight hours, and other sources of generation can be throttled to account for solar's lack of generation at night.

Other sources being natural gas plants? Great plan.

Yes, it does make more sense to use natural gas between 6-10pm than it does it use it 24/7, like we do now.

And/or use hydro, which can also be throttled.

https://www.eia.gov/electricity/gridmonitor/expanded-view/el...

Until renewables are fully built out, storage is useless. So we burn natural gas at night for a while. When there is enough generating capacity to supply demand and charge storage at the same time, then we install the storage and charge it. Storage will be radically cheaper at that time than now.

In the meantime, every spare dollar should go to building out renewables. At some point spending on mined gas declines naturally because it is the most expensive energy.

But why do you want us to move to 100% solar and nothing else? No power system in the world depends on only one type of power.

You're just making things up to prove your conclusion.

In most of the US, electricity usage in afternoons in July is 50-100% higher than during the middle of the night in January[1]. Your intuition about when the most electricity is used is dead wrong.

[1] https://www.eia.gov/todayinenergy/detail.php?id=42915

Does this hold true when controlled for heat source? If we are pushing to be off fossil fuels, it'd be worth knowing how much we will need in order to convert all existing methane/propane/oil furnaces over to heat pumps, and what that looks like during cold winter nights.

The sun definitely shines all day. If it stopped shining at night, you wouldn't see a full moon

I don't think that's relevant to his point

AC is a huge load for much of the US. Covering that with solar is a huge win even if you need something else for 10pm. Don’t let perfect be the enemy of good.

And not just AC, but the service economy runs during daytime for the most part.

AC is a huge load now, with electrification heating will eclipse it. I can confirm this via my electric bill with a heat pump.

New AC designs seem to get about 1-2% more efficient every year, so we're making progress on both ends.

It's funny people always forget this. There is a much bigger temperature differential to overcome to provide heating compared to cooling in most of the US. Burning natural gas for various forms of heat is probably the most energy intensive thing most houses do. Electricity is more efficient, but once heating is electrified, most residential electricity will be used to heat homes and water.

With a modern heat pump, it is more efficient (most of the time) to burn natural gas at the power plant and then use the generated electricity to heat the home (after accounting for generation and line losses, and other efficiency drains) than it is to burn the gas in a modern, super-efficient gas furnace in the home.

So whether we fully renewablize™ the grid or not, we still should encourage (read: subsidize) the replacement of gas and heating oil furnaces with heat pumps.

This intuition can be kind of wrong - Long haul grid power isn't cheap, and it may turn out that large batteries on location will be more effective in many cases.

Everybody will have everything. You draw down local batteries first, pull from transmission lines, convert from your long-term tankage, according to what your AI decides. Transmission line power costs money, drawing down your batteries causes wear, long-term storage has lower round-trip efficiency, yada yada.

A 10MV DC national transmission system would make a lot of sense.

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