Gravity batteries try to beat chemical ones with winches, weights, mine shafts • Hacker News Board

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#191

Post by aquark » Sat, Apr 24, 2021, 4:37 PM UTC

bjourne wrote: post #168

hutzlibu wrote: post #145

Earlier quoted context omitted.

Maybe I do not understand it fully (ne pas parle de francais), but where do they game the system? You buy cheap when you have storage and sell expensive when demand goes up. Pretty much how the market should work? This way there is incentive to balance it out (by creating storage) - and in this case stabilize the grid. When the grid would become more flexible, so even homeowners can do this with their solar panels an…

It's not gaming the system, it is arbitrage. However, it is pretty terrible for producers unable to exploit price swings. E.g a nuclear plant produces electricity at a fixed cost and may sell it at a loss when the price is low, but recoups the losses when the price is high. Since arbitrage smooth out the price peaks, it damages nuclear's profitability. One could say that's too bad for nuclear, others (nuclear lobbyis…

If nuclear can offer sustained cheaper than average generation then the market would allow a long term fixed price contract — they shouldn’t need to sell their full output at spot rates. Consumers that want predictability could buy on these contracts.

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#192

Post by darawk » Sat, Apr 24, 2021, 4:37 PM UTC

wizzwizz4 wrote: post #137

darawk wrote: post #44

Earlier quoted context omitted.

Not to disagree with your underlying point, but I think it might be more constructive to frame the problem as a failure to internalize the costs, rather than a focus on money. Ultimately we do need a fungible way to compare solutions, and money is the simplest way to do that. We just need to figure out how to effectively internalize those externalities to the price.

Cost functions have an implied ethical system behind them. Using money is just waving your hands over it and going “well, money is objective , so we don't need a value system” – but there's still a value system there. It's like “machine learning” in that regard; there's no magic.

Money is just a fungible unit of comparison for types of value, nothing more.

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#193

Post by amluto » Sat, Apr 24, 2021, 4:44 PM UTC

bjourne wrote: post #164

martinald wrote: post #127

Earlier quoted context omitted.

Not true in northern European countries. The problem isn't day to day regulation, it's the massive demand in cold snaps in winter (when there is very little wind generation - cold weather tends to have little wind). You're talking balancing 20-30GW of additional demand with little solar/wind generation for weeks/months - probably at least 1TWh of storage required for the UK alone. Keep in mind this will only get wors…

Homes in the UK are poorly insulated, likely due to a previous over-reliance on fossil fuels. https://www.theguardian.com/environment/damian-carrington-bl... Better insulation and switching to district heating where applicable could yield massive savings.

District heating still needs heat to come from somewhere. Admittedly, low grade heat like is used for heating can be stored for days in the form of hot water in insulated tanks.

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#194

Post by masklinn » Sat, Apr 24, 2021, 4:48 PM UTC

Scoundreller wrote: post #165

thirdlamp wrote: post #94

Earlier quoted context omitted.

What if we used load bearing batteries as part of the tower structure?

I was thinking what if we used buildings built on jacks as our source of mass. Big one are largely built on pilings anyway, and even small ones on softer ground. Going to be a lot of flexing though. Nice thing is that some of the “inefficient” heat may be usable on-site: and you may get compressed air as an output that could be usable directly.

> I was thinking what if we used buildings built on jacks as our source of mass.

Then you've got no height. Plus buildings are not dense so it's a pain in the ass, and when (not if) the jacks fail you're out a building.

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#195

Post by VBprogrammer » Sat, Apr 24, 2021, 4:49 PM UTC

audunw wrote: post #90

rakoo wrote: post #48

As usual everyone is fixated on price when the real hurdle will be scale. If we're going to replace our existing fossil fuel plants we need at least as much capacity. A quick grep in the article tells me these guys have a plan for a 4MW plant that involves a 1km shaft. That's the same order of magnitude as a single wind turbine, which is already one of the worst ratio of power output per quantity of resource and land…

It's a common misconception that energy storage needs to handle all the power needs of an area for a significant time. The most immediate need for energy storage is frequency regulation, and short hours-long dips in power output. If we can solve that we can scale renewables very far. For days-long dips in power output, it's probably better to keep some gas power plants on stand-by. I think many areas of the world has…

> It's a common misconception that energy storage needs to handle all the power needs of an area for a significant time.

You are only looking one half of the problem. Wind power in the UK has a power factor of about 35%. What that means is to meet the average demand from the UK electricity grid we'd need not install 3 times as much Wind Power as the demand. This is borne out in the current figures, we have some 25GW installed wind power for an average of about 6GW supplied. If we have enough renewables to meet the demand on average, a windy day across the UK is going to result in a glut of power.

If we don't have ways of storing that modestly efficiently then our only choice will be to take turbines out of service, increasing the overall cost.

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#196

Post by VLM » Sat, Apr 24, 2021, 4:52 PM UTC

jillesvangurp wrote: post #77

rakoo wrote: post #48

As usual everyone is fixated on price when the real hurdle will be scale. If we're going to replace our existing fossil fuel plants we need at least as much capacity. A quick grep in the article tells me these guys have a plan for a 4MW plant that involves a 1km shaft. That's the same order of magnitude as a single wind turbine, which is already one of the worst ratio of power output per quantity of resource and land…

Your assumption that we need that much storage is simply wrong. This pops up in just about any article on HN mentioning batteries. Somebody will jump to the wrong conclusion that we need to provide massive amounts of battery storage and that therefore we need coal/nuclear/etc. (i.e. really expensive ways to generate energy) because buying so many batteries is obviously stupendously expensive. It's a popular argument…

The cheapest "energy storage" is bandwidth and demand based billing.

The required battery storage cost to guarantee my 3 KW electric clothes dryer could theoretically operate 24x7 when needed after three weeks of cloudy windless weather at midnight is staggering. The alternative is demand based billing and program my dryer to never accept a KWh that costs more than say, seven cents. On a minute by minute basis I don't care if my "hour" dryer cycle takes 65 minutes because a cloud passed overhead and it slept for five minutes. Its also worth considering that "in theory" people who design for max theoretical load MUST assume my clothes dryer will run for 24 hours a day 7 days a week, when in practice I have never done more than five hour long loads of laundry in a row, and that was after traveling out of country for two weeks (after zero electrical demand for 14 days)

Even data centers can do stuff like vmware vmotion running virtual hosts off a cloudy cloud data center to a sunny cloud data center with no user interruption.

The idea that the wall outlet is an infinite source of energy is going away, or if its demanded for a hospital operating room or nuclear power plant or something, those KWh are going to cost like $5 or something similar and that's just how its going to be. Its not going to be that much suffering; right now my multi KW airconditioner instantly starts up when the thermostat says go, and in a decade maybe the electric company contract says it's guaranteed to start within the next ten minutes 99% of the time, and that sounds like a nice deal if it cuts my bill in half and eliminates CO2 output.

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#197

Post by [deleted] » Sat, Apr 24, 2021, 4:55 PM UTC

[deleted]

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#198

Post by raverbashing » Sat, Apr 24, 2021, 5:03 PM UTC

ms4720 wrote: post #147

cogman10 wrote: post #136

Earlier quoted context omitted.

This seems like a "running before we can walk" statement. Until we can handle day to day problems, it seems weird to worry about edge cases. I imagine as we transition to renewables and storage we will still have fossil fuel peeker plants to handle these sorts of snaps. It won't be until our power storage is far more beefed up that we'll shut those down, and that will take years.

A cold snap like that can happen every 3-5 years, think really cold February. If you don't have the capacity to handle it people will die and lots of things will break. It is not an edgcase

Agree. See Texas for an example.

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#199

Post by ericd » Sat, Apr 24, 2021, 5:10 PM UTC

martinald wrote: post #127

audunw wrote: post #90

Earlier quoted context omitted.

It's a common misconception that energy storage needs to handle all the power needs of an area for a significant time. The most immediate need for energy storage is frequency regulation, and short hours-long dips in power output. If we can solve that we can scale renewables very far. For days-long dips in power output, it's probably better to keep some gas power plants on stand-by. I think many areas of the world has…

Not true in northern European countries. The problem isn't day to day regulation, it's the massive demand in cold snaps in winter (when there is very little wind generation - cold weather tends to have little wind). You're talking balancing 20-30GW of additional demand with little solar/wind generation for weeks/months - probably at least 1TWh of storage required for the UK alone. Keep in mind this will only get wors…

Wrt cold snaps being a big problem, it seems like we could just massively insulate dwelling and improve our energy use auditing, if it became necessary? Vacuum insulation panels are a bit pricey, but they’re crazy insulative for the thickness. If we’re willing to deal with thicker walls, there are a variety of other options that are downright cheap (shredded newspaper, for example).

We’ve been designing around super cheap on-demand energy for a while now, but we did manage before that.

Re: Gravity batteries try to beat chemical ones with winches, weights, mine shafts

#200

Post by oauea » Sat, Apr 24, 2021, 5:14 PM UTC

silon42 wrote: post #173

f6v wrote: post #160

Earlier quoted context omitted.

> This seems like a "running before we can walk" statement. Europe tries to be at a forefront of green energy. No sun/wind is a real issue there, not just an edge case.

Yup, where I live there can be 3 months of fog/clouds... meaning minimal wind / sun.

Global warming will resolve that issue soon enough.