Japan Building Giant Battery Systems to Store Solar Power | Hacker News Reader

Japan Building Giant Battery Systems to Store Solar Power

blogs.wsj.com

78 pointsprostoalex30 comments

That's 600 MWh for 257 million USD. Tesla's powerwall has 10 KWh for 3500 USD. Interestingly, that's about the same price point.

Efficiency-wise, the centralized Japanese solution makes probably more sense for large centralized solar plants, whereas Tesla's model probably makes more sense for self-owned solar panels.

Upfront costs might be similar though this includes total costs (Land, installation, AC-DC converter, etc) where the tesla does not. However, efficiency is probably higher and the matence costs are probably far lower.

PS: The tesla battery actually claimes an 'inflated' effecency level (92%), by not including inverters, though as it's designed for DC solar systems that may be reasonable.

I gather that Tesla's model is also targeted at people who may also wish to start storing power they buy off the grid at times when the cost is lower (as well as from locally generated solar, turbines, etc).

Price point commonality may be more coincidence than anything else. There's a philosophical question in there for some (probably small) number of customers -- whether they wish to remain beholden to vendors of electricity, at whatever rate is determined by the vendor at the time.

Which Tesla model? There are 2: the Powerwall for home use, and the Powerpack, for businesses. The Powerpack starts at 100kWh, and goes as big as you have money for. Initial reservations are mainly for the Powerpack.

https://en.wikipedia.org/wiki/Tesla_Powerwall

Grid storage that stabilizes a grid is much more valuable than storage of power to shift production to non-peak times.

Whats the difference between stabilizing a grid and storing power produced at non-peak times so you can use it at peak times?

One is much more profitable, because it requires much faster response times.

Grid storage that stabilizes a grid [...]

Your comment made me think - what if a state-power or hacker group were able to make a large number of these energy storage units dump their energy back on the grid en mass? Would there be ways to protect the grid from being overloaded by a centralized energy store dumping its energy?

With ten billion dollars we could have one million houses with solar roofs and powerwalls, a whole city unplugged. I'd like to see government invest in a project like that.

I believe distributed generation is the future.

"the lack of compatibility between regional power utility grids."

For folks outside the country, the grids here are actually like 19th century European railroad gauges in different countries. Meaning, after the tsunami in the north, when the nuclear power plants were shut down, they literally could not move electricity from one part of the country to another where it was needed (or could, but it was crazily difficult).

I'll just note that, since you need AC-DC conversion for a battery anyway, you could build one with two converters connected to two grids ...

(Good illustration of sunk costs though. Presumably it's prohibitively expensive to merge the grids.)

Yes, japan is split into a 60 Hz (west) and a 50 Hz (east) power distribution systems. They do have four main frequency converter stations that can move power between the two networks, three of them are shown on this power distribution map:

https://en.wikipedia.org/wiki/Shin_Shinano#/media/File:Power...

Taken together they have a capacity of around one Gigawatt. Here is some more information on the used technology:

https://en.wikipedia.org/wiki/Higashi-Shimizu_Frequency_Conv...

https://en.wikipedia.org/wiki/Sakuma_Dam#HVDC_frequency_conv...

Taken together they have a capacity of around one Gigawatt.

Not even enough to power a flux capacitor :(

How did that happen?

Quoting from https://en.wikipedia.org/wiki/Energy_in_Japan#National_grid

"The two grids were originally developed by separate companies. [..] In 1885 demand had grown enough that TELCO bought generation equipment from AEG of Germany. The same happened in the western parts of Japan with General Electric being the supplier to Osaka Electric Lamp. GE's equipment used the US standard 60 Hz while AEG's equipment used the European standard of 50 Hz."

AFAIK they never managed to convert the network to a common frequency due to cost concerns and politics.

Google doesn't help me, but my wife often tells me that our area (along the coast of Suruga bay in Shizuoka prefecture) has the most annual sunshine in all of Japan (I won't argue with her ;-) ). Definitely the number of solar installations here is dramatically rising. Practically every day I see a new one. 5 years ago it was wind turbines (it's also insanely windy here most of the time...)

Shizuoka is home to a very large amount of car and motorcylce manufacturing and after the the Tohoku earthquake they got creative with scheduling workers based on available power. My understanding is that the big manufacturers made a rota took turns using the power. If they manage to get a very large amount of solar power running (which it definitely looks like they are aiming for), I wonder if they will end up scheduling work based on the weather report.

They should put solar panels on wind turbines then :)

Listen to this one. He's/She's going places.

Here's one map of solar insolation for Japan:

http://solargis.info/doc/_pics/freemaps/1000px/ghi/SolarGIS-...

...and for the world:

http://solargis.info/doc/_pics/freemaps/1000px/ghi/SolarGIS-...

Cool! Thanks. Definitely it's in the darkest red area, so she could well be right!

Finally someone starts putting two and two together. Mankind's preoccupation with lethal / more dangerous power conversion methods has lasted more than long enough.

Still smaller than the US's largest battery.

https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Sta...

3-Gigawatt turbines for 10-hours == roughly 30 Gigawatt-hours of storage potential. IIRC, the project only cost $1.6 Billion in 70s money, so after some inflation... it's still a pretty cheap storage mechanism.

I love the simplicity of water / gravity energy storage. https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit...

It obviously requires the right kind of terrain etc, but it is very very cool.

50000 kilowatt, for how many milliseconds? The phone in my pocket has a 500 _giga_watt battery. What a pity it's only 700mAh...

Not really true, I believe lithium batteries have a discharge rate limit, but still good point.

I know you probably already realise this, but they obviously mean kWh.

I normally wouldn't comment, but to most people a kW is a kWh and, in context, it's obvious they're talking about kWh.

It's possible that they accidentally quoted the maximum power rather than the energy stored, which would make the figure correct but not what most would expect.

The linked document mentions 50,000 kW and 300,000 kWh.

Like say you get an electric car and people ask what is the range, and you answer the number for the top speed?

It's inexcusable for journalists reporting on any energy issue.

You just can't give any slack on this point. It's 100% wrong to say one thing and mean the other thing.

No, it has not. You cannot get the energy out of that battery that quick.

That makes a huge difference. For example, TNT has about a tenth of the specific energy per kg of gasoline (4.6 MJ/ kg vs 44 MJ/kg; https://en.wikipedia.org/wiki/Energy_density), but is more useful as a bomb because you can get the energy out very quickly.

If you could get that amount of power out of a mobile phone, it would probably be a bomb.

The internal resistance of a battery limits the amount of current that it can produce: https://en.wikipedia.org/wiki/Internal_resistance

Reply on news.ycombinator.com