Forgot your password?
typodupeerror

Submission + - Gravitricity energy storage goes bankrupt, but two others keep on trying (autonocion.com)

Geoffrey.landis writes: Gravitricity, a Scottins corporation that proposed using gravitational potential energy to store electrical energy, went bankrupt at the end of 2025. The basic idea is so simple, even a freshman physics student could describe it: use an electric motor to raise a weight up against gravity, and then when you need energy, lower the weight back down, and use the energy to run a generator. The difficulty, however, is in scale. Their proof of concept unit, a 40-ton block of steel falling the height of a 30-story building, stores an amount of energy equal to about eight hours of an average American home’s electricity. Their solution was to go big: there are literally millions of abandoned mine shafts around the world, many of them kilometer and more deep. They proposed a full GraviStore system would hang up to 24 separate weights of 500 metric tons each from cabled winches inside a single shaft. Twelve thousand metric tons of suspended steel, going up and down forever. But turning their concept into a reality ended up spending money faster than it could be invested, and, so quietly it took investors three months to even notice, the company went bankrupt.
But the basic concept may not be dead. Several other companies are still working at turning the concept into reality. And hundreds of thousands of abandoned mines are scattered across the United States, most of them a liability, a few of them with a kilometer of free vertical drop and a hoist house and a grid connection already sitting on site.

Comment Re:"Reasoning" (Score 1) 187

You are speaking irrelevant nonsense. LLMs are trained in words

They are not. They are trained in tokens. Tokens do not align with word boundaries, and an arbitrary word can be tokenized in many different ways.

and they think in words

They do not. They don't even think in tokens. The process is: words are split to tokens, tokens point to an embedding position (latent space) while RoPE encodes a relative position, and all reasoning is done within latent space, which is not at all verbal (concepts are directions in latent space, and math is done on concepts, not words).

Comment Re:Why not put a generator on the engine? (Score 1) 44

Also, a note: when spec'ing a generator, you need to know how much you're planning to use it vs. batteries. If it's only going to be used rarely, you prefer low mass, low volume, low cost, and low maintenance when unused (at the cost of low efficiency and higher maintenance in use), whereas if it's going to be used a lot, you prefer high efficiency and low maintenance cost in use, even if at the cost of higher mass, volume, cost, and maintenance when unused. In the former case, you'd prefer to allocate that extra mass, volume, and money into a larger battery pack.

Comment Re:Why not put a generator on the engine? (Score 1) 44

That's why you don't use a tiny petrol generator? Diesel generator efficiencies are roughly:

Small backup generator (1-15kW): ~20-28%
Midsize backup generator (20-200kW): ~30-35%
Large industrial generator (200-2000kW): ~35-42%

Also, ironically this company's plan of the trailer providing a boost will actually make the tractor less efficient. ICE engines use "brake specific fuel consumption" (BSFC) graphs to plot their efficiencies across different RPMs and different torques. You can see an example for a small diesel engine here. Note that they require very high torque conditions and relatively high power conditions to be efficient. You can change the balance between torque and RPM within a given power band (blue) via gearing but gearing doesn't change what power band you're in. If you're in a low power band, you're fundamentally forced into inefficiency (note also that you're not going to be driving around at 1000 RPM just over a stall all the time).

Indeed, if you were forced into a low power band, you'd actually be better off with a series hybrid powertrain, as the engine can alternate between operating in an efficient powerband and shutting down. Of course, parallel hybrids are more efficient than series (albeit with added complexity and mass).

Comment Re:between 165k and 222k usd? (Score 2) 44

Unfortunately, the math doesn't work that way (even ignoring that a 400kWh battery is very small). Battery packs taper the closer you get to full, they're not a constant power all the way. Unless your battery pack can take 400kW at 80%, you're not charging that quickly.

Also, while 40 mins is fine in Europe (breaks: 45 minutes every 4,5 hours of driving... though using 70% of a 400kWh pack on a loaded class 8 truck going even at a slow 80kph will only take you 2 1/2h of driving in "average" conditions, so the truck's range is fundamentally undersized), the US is 30 minutes total break in 11 hours of driving, so ~6 hours on your first leg and ~5h on your second leg with 30 minutes to fill that 5h of driving. And US speed limits are usually faster for trucks than in the EU, so higher consumption. EU really needs 600kWh and >=600kW charging, while the US needs 800-1000kWh and >MW charging.

Note that in all of this we're assuming efficient-shaped trucks (Tesla Semi or the like), not your typical EU bricks, along with a well optimized powertrain and an efficient tyre config. If not, you need to increase those packs and charge powers further.

Comment Re:The billionares can leave, but they're (Score 1) 93

So the Billionaire can leave, but he'll end up controlling his company remotely from out of state unless he can do everything with AI or make do with mediocre employees or use AI and have a few less-than-stellar employees for grunt tasks.

And then wait for California to introduce a law that if the CEO works remotely from the company, then workers are allowed to work remotely as well. And by remotely, I mean the CEO lives in a place where no substantial office of the company exists. So if they live in Florida, they will need to set up an office in Florida where the CEO will go to and staffed with a certain number of people who also come in to work daily. Say, 10 to 20 people must work in the same office as the CEO to be not considered working remote. And those 10 to 20 people must regularly come into the office.

And said office must in a properly zoned for business. So no inviting 10 family members for an in-home office.

If nothing else, Florida and Texas now see a boom in CEOs having to open offices and hire people.

Comment Who are they? Secretaries (Score 4, Insightful) 68

Here's the article's actual answer to the question (not in the summary): "The most affected jobs are secretaries, are routine clerks," said Michelle Yin, one of the working paper's authors...

Secretarial jobs were already cataclysmically wiped out by the word processing/computer revolution. It's hard to remember anymore how ubiquitous secretaries were to businesses.

However, turns out that this previous revolution didn't reduce the workforce, because the number of IT support personnel required increased directly as the number of secretaries decreased.

Slashdot Top Deals

Nothing ever becomes real until it is experienced. - John Keats

Working...