EDIT: Submarine power transportation is indeed on the list
Not transoceanic, but there are two projects currently proposed that will – when constructed – break the current record for the “longest undersea power transmission cable” (a record currently held by the North Sea Link at 720 km, or 450 miles.)
One of these projects is the Xlinks Morocco-UK Power Project which aims to lay 3,800 km (2,400 miles) of cable and sell Morocco’s solar power to England.
There is, as of yet, not enough cable in the world to even begin this project. The company proposing the project is building factories to produce this cable.
The other is the Australia-Asia Power Link, which aims to provide Australian solar power to Singapore using a 4,500 km (2,800 miles) undersea cable.
Where the Xlinks project ran into a “not enough cable in the world” problem, Sun Cable’s AAPL has apparently been running into a “not enough money in the world” problem, as it has repeatedly gotten into trouble with its investors.
EDIT: But also, storage is scaling up
@[email protected] provided a fantastic link to a lot of energy storage mediums that are already in use in various grids across the world. These include (and the link the professor provided gives an excellent short summary on each)
- Pumped hydroelectric
- Compressed Air Energy Storage (CAES)
- Flywheels
- Supercapacitors
- And just plain batteries
Also, this wasn’t in the Gumby’s answer, but Finland’s Vatajankoski power plant uses a hot sand battery during its high-demand, low-production hours.
Hydrogen is projected to grow
@[email protected] noted that hydrogen has advantages no other energy storage medium possesses: duration of storage and ease of piping/shipping. This is probably why numerous governments are investing in hydrogen production, and why Wood Mackenzie projects what looks like a 200-fold increase in production by the year 2050. (It’s a graph. I’m looking at a graph, so I am only estimating.)
Okay any engineers up for a hypothetical? As others have pointed out, things like wind, nuclear, and other things are sensible answers. BUT WHAT ABOUT AN INSANE ANSWER?
It obviously would be prohibitive to have a colossal “city battery” that stored excess from the day to be used at night, and environmentally would present issues making a city sized battery. But what about a non-traditional kinetic battery (think F1’s KERS). What if there was say a building in the middle of the city, and inside is a metal disk made of solid steel that’s a foot thick, and 500 feet across, on an electromagnetic cushion, housed in a room with negative pressure or a vacuum. During the day, the excess solar energy from the city powers this to gradually spin faster and faster, and during the night this process is reversed with the enormous amount of kinetic energy feeding a powerstation generator that would provide power at night. Okay, I told you it was an insane hypothetical, but as thought experiment humour me. It would by definition be a battery, but one that wouldn’t deteroriate in the same was as a chemical battery, without the same environmental impact of involving all the cobalt, lithium, etc., although it admittedly would be pretty wildly expensive just from a space, and material cost of the disk perspective. How big would this need to be? Is this remotely possible? I mean WAY less power is used at night after all. Thoughts?
In case you don’t already know, that concept has a name: Fly Wheels (wiki link: https://en.wikipedia.org/wiki/Flywheel ).
One of their main problems is that, as you pump enough energy into them to justify their cost compared to other storage mechanisms, the spinning mass becomes more and more of a danger if it ever breaks loose. Not to mention the gyroscopic effect making a “fully charged” fly wheel very hard to safely move.
The statistic you’re looking for is energy density. It’s usually expressed as Watthour per kilo(Wh/kg). Li-ion batteries are somewhere around 300Wh/kg, or about 1 megajoule though less if you’re making it into a building.
Lifting a big weight provides you with Mass x 9.81 x Height amount of joules. So lifting 1 kg for 100m gives you 1x10x100~ 1 kilojoule.
So, to charge my 300kg, 32.000 Wh Nissan leaf battery (130Wh/kg, what you get when you actually build batteries in the real world), you would need to lift a mass of 115tons to 100 meters. So to charge a single car, at 100% efficiency, you need to lift 72 entire cars. Just so I can drive to work and back. And real-world efficiency is far below 100%, just think of the friction.
I think you’ve spotted the reason why we don’t actually build gravity batteries. Imagine lifting 115 tons to 100m, that requires a massive crane, itself weighting nearly half that. That’s why all gravity storage in existence basically consists of pumping water uphill, onto pre-existing mountains and lakes that nobody had to fabricate out of concrete and steel.
There’s a company in the UK that proposes building gravity batteries using existing shafts that were excavated for mining.
I like insane hypotheticals that are discussed as hypocriticals. Not an engineer on paper, but these are my thoughts.
I think a very heavy weight that fits neatly inside of a protective structure with room to raise and lower it would be the way to get a kinetic battery. I’m talking about a platform stacked with concrete and rocks and sand and building demolition debris until it has stacked up to 2 or 3 stories tall. Then build a basic shell around it to blend into the town and have that 6 to 8 stories tall. The weight would tug at cables or press down on a hydraulic cylinder at a constant rate. A motor would then spin a large set of extreme reduction gears to raise the weight when there’s extra power coming in. Then, the tremendous weight could drive the reduction gears to spin the motor as a generator at a constant rate and make reliable power.
The less crazy version of this has been proposed, a set of cranes stacking up and lowering down more reasonably size blocks to store power inside of a tall structure.
None of this is practical. You can’t build a tower like this for any real storage, it’s just not efficient. The only effective method is running a train up a mountain, or pumping water uphill. If you have to actually build a mountain a first, it’s not going to work.