Storing energy in the summer to be used in the winter probably isn't going to ever be practical with batteries. (Maybe it's practical by using electricity to make synthetic liquid fuels? That wouldn't be very efficient, though.) Batteries are useful for buffering shorter-term variations, like the day/night cycle.
There are some alternatives, though. One is to just build enough spare capacity into the system that one can still run a surplus on cloudy winter days when the winds aren't blowing.
Better I think is to connect power grids to even loads around. Barring megavolcano eruptions or nuclear winter, the sun is always shining somewhere in the world. And the wind is always blowing somewhere.
I think the thing that's needed most right now (aside from just more solar or wind plants everywhere) is high-capacity transcontinental grid connections. The United States should be able to buy solar power from the Sahara when it's night here, and sell surplus solar to Europe and Asia when the sun is shining here. This makes renewable energy much more attractive because there's always a buyer or a seller somewhere, and batteries aren't strictly needed.
Fossil fuel plants can continue to exist as emergency backup power sources in case something happens to the HVDC links. Ideally we'd get to the point where they never need to be used.
Apparently Chile and China are working on a plan whereby Chile supplies China with solar power via a trans-pacific HVDC line [1]. We need more of that: connections between North America and Europe, connections between South America and Africa, and so on.
"The project’s salt caverns will be capable of holding more than 5,500 metric tonnes of hydrogen. From an energy storage perspective, one cavern holds the equivalent of 150 gigawatt hours (GWh) of carbon-free dispatchable energy and/or decarbonized fuel that can be used in other industries. By comparison, a U.S. Energy Information Administration (EIA) 2020 report estimates the current installed base of battery energy storage across the U.S. at 1.2 GWh."
(The formation there has room for 100 such caverns.)
Metric tonnes: People get confused if you just say tonnes because there are some traditional ton units that are of similar scale but different. So, "metric tonnes" avoids this confusion even when it isn't strictly necessary in written English.
If you're wondering why you'd measure hydrogen in tonnes at all, well, it's a measure of mass, you could tell people how many hydrogen atoms it is but that's some mind-bogglingly huge number so it just feels meaningless, a tonne of something you can imagine, even if doing so for hydrogen is a stretch.
A metric ton(ne), by the way, is the same quantity as the unambiguous and compositional, but rarely used, "megagram". (Oh, but kilotons and megatons are usually units of energy as shorthand for burning TNT.)
> Maybe it's practical by using electricity to make synthetic liquid fuels?
That was my point. For long term storage you can convert electricity in green hydrogen. The round trip efficiency is not great, but it's not really that bad either. Until we develop the infrastructure to do that, we just use natural gas.
Solar, wind, batteries (for short term storage) and nat gas for peaker plants will get you to 20% net emissions. Hydrogen will get you to zero.
> Barring megavolcano eruptions or nuclear winter, the sun is always shining somewhere in the world.
Yeah, but sometimes that somewhere is mostly just the Pacific Ocean. If you look at the sun around Thursday, December 22, 2022 at 00:48:00[1], there's not a whole lot of land area with great sun.
Of course, if you overprovision, and interconnect, and have some peaker plants, and make syngas (or whatever) when there's overproduction to use in the peaker plants (and probably elsewhere, liquid fuels are really handy if the price is right), we can probably make it work.
I wouldn't build a solar plant in the Sahara though; sand is going to ruin everything if the heat doesn't first.
There are some alternatives, though. One is to just build enough spare capacity into the system that one can still run a surplus on cloudy winter days when the winds aren't blowing.
Better I think is to connect power grids to even loads around. Barring megavolcano eruptions or nuclear winter, the sun is always shining somewhere in the world. And the wind is always blowing somewhere.
I think the thing that's needed most right now (aside from just more solar or wind plants everywhere) is high-capacity transcontinental grid connections. The United States should be able to buy solar power from the Sahara when it's night here, and sell surplus solar to Europe and Asia when the sun is shining here. This makes renewable energy much more attractive because there's always a buyer or a seller somewhere, and batteries aren't strictly needed.
Fossil fuel plants can continue to exist as emergency backup power sources in case something happens to the HVDC links. Ideally we'd get to the point where they never need to be used.
Apparently Chile and China are working on a plan whereby Chile supplies China with solar power via a trans-pacific HVDC line [1]. We need more of that: connections between North America and Europe, connections between South America and Africa, and so on.
[1] https://news.ycombinator.com/item?id=29230066