5 ms·

Stopped reading at a total cost of more than $300 per MWh for batteries. Quick back-of-the-napkin calculation: Car batteries come in at less than $100/KWh. The

Stopped reading at a total cost of more than $300 per MWh for batteries. Quick back-of-the-napkin calculation: Car batteries come in at less than $100/KWh. They're good for at least 1000 cycles at 80% capacity. That gives us at least 0.8MWh for a 100$ investment. It's very, very unlikely that initial construction of the site and operational costs more than triple that price.

alexchamberlain 6y ago
Their marketing has the LCOS of those 2 solutions the other way around - $171 for Gravity, $367 for Litium Ion batteries. See https://gravitricity.com/technology/ https://gravitricity.com/technology/
- PeterisP 6y ago
  Too bad they don't seem to provide the actual report anywhere (and neither does ICL), they just quote a single chart from that without any details. This feels fishy to me - I'd want to look into the cost basis they used, as a key problem with comparisons against batteries is that the battery cost has changed so much over the recent years (halving every 5 years or so), and many studies quote their battery price calculations on older reports that are now off by a large multiple. $367 of LI batteries at year X is $171 of LI batteries at year X+5 and $86 at year X+10, so it's important to look at what the X is in their study. And of course, we should consider that chemical battery costs are expected to decrease in the near future, while the cost well-established mechanical components would stay stable.
  - alexchamberlain 6y ago
    Whilst I agree the components of a mechanical battery are probably going to stay stable, I think Gravitricity have an opportunity to commoditise the design and install near sporadic renewables like wind. Bias: I participated in their crowdfunding campaign.
_rpd 6y ago
Here’s what the article says about cost: > For a 25-year project, he estimates that Gravitricity would cost $171 for each megawatt-hour. Jessika Trancik, an energy storage researcher at the Massachusetts Institute of Technology, says that number is aspirational and still needs to be supported with field data. But Schmidt’s calculation of the lifetime cost per megawatt-hour for lithium-ion batteries, $367, is more than twice as much. Flow batteries, a promising grid-scale technology that stores charge in large tanks of liquid electrolyte, come in at $274 per megawatt-hour
o_p 6y ago
This doesnt account the short duration of batteries, I have to replace them every time they go past their lifetime, so in the long term their cost is much higher
- PeterisP 6y ago
  The heavy machinery with moving parts lifting thousands and thousands of tons is also going to need maintenance and wear&tear replacements. The problem with scale is that all these proposed gravity batteries need much, much more machinery than an equivalent pumped capacity pumped hydro or chemical battery plant.
  - polypodiopsi 6y ago
    Out of interest: do you have experience with mechanical engeneering or is this more of a common sense speculation?
  - mplewis 6y ago
    This is something made easier by the fact that we understand how mechanical designs age. We've built high-standing structures with parts that move in a similar way that last decades. We understand how to maintain those structures without totally replacing them.
simion314 6y ago
You should finish reading or find a similar storage company that sells batteries and see how much they charge.
kurthr 6y ago
What you have described would last for 1000 days used to even out daily (solar) power demand/supply. So for a 25yr capability it would cost 8x more? I would hope not, and I think you could get 3000 cycles by restricting temperature and charge/discharge, but that still requires 2.5-3x higher cost and puts this solution as very competitive with current battery solutions.
- choeger 6y ago
  The cost was given purely in terms of MWh.
cheschire 6y ago
I wish that cost basis wasn't the only consideration when evaluating energy storage, but we're so accustomed to money being the great equalizer that things without a financial cost associated are often overlooked. What is the $/MWh cost associated with mining for, recycling, and disposing of battery components? What about the third order effects of centralizing control over the fuel source within only a handful of countries[0]? What's the $/MWh of the political shifts? I can't safely make assumptions about why you personally stopped reading after cost came up, but it seems to be a common reaction at this point. "Show me the money!" tends to end most conversations about energy these days. 0: https://unctad.org/news/demand-raw-materials-electric-car-batteries-set-rise-further https://unctad.org/news/demand-raw-materials-electric-car-ba...
- darawk 6y ago
  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.
  - wizzwizz4 6y ago
    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.
    - darawk 6y ago
      Money is just a fungible unit of comparison for types of value, nothing more.
      - Qwertious 6y ago
        In that case, gas plants are the best peaker option in most places as in most place CO2 and methane emissions cost $0.
imtringued 6y ago
The only savings grace with these gravity systems is that they could last 100 years. Gravity is a very poor of storing energy. Height is limited by practicality. Reusing old mine shafts is just a code word for unaffordable. You need to increase the amount of mass that you move around, therefore your system should be infinitely scalable. By limiting yourself to mineshafts you have reduced the scalability option and the entire project becomes a scam.
billytetrud 6y ago
Car batteries don't last decades. Multiply that $100 by 5 years and you can see how the price racks up

alexchamberlain 6y ago

Their marketing has the LCOS of those 2 solutions the other way around - $171 for Gravity, $367 for Litium Ion batteries. See https://gravitricity.com/technology/ https://gravitricity.com/technology/

PeterisP 6y ago
Too bad they don't seem to provide the actual report anywhere (and neither does ICL), they just quote a single chart from that without any details. This feels fishy to me - I'd want to look into the cost basis they used, as a key problem with comparisons against batteries is that the battery cost has changed so much over the recent years (halving every 5 years or so), and many studies quote their battery price calculations on older reports that are now off by a large multiple. $367 of LI batteries at year X is $171 of LI batteries at year X+5 and $86 at year X+10, so it's important to look at what the X is in their study. And of course, we should consider that chemical battery costs are expected to decrease in the near future, while the cost well-established mechanical components would stay stable.
- alexchamberlain 6y ago
  Whilst I agree the components of a mechanical battery are probably going to stay stable, I think Gravitricity have an opportunity to commoditise the design and install near sporadic renewables like wind. Bias: I participated in their crowdfunding campaign.

_rpd 6y ago

Here’s what the article says about cost: > For a 25-year project, he estimates that Gravitricity would cost $171 for each megawatt-hour. Jessika Trancik, an energy storage researcher at the Massachusetts Institute of Technology, says that number is aspirational and still needs to be supported with field data. But Schmidt’s calculation of the lifetime cost per megawatt-hour for lithium-ion batteries, $367, is more than twice as much. Flow batteries, a promising grid-scale technology that stores charge in large tanks of liquid electrolyte, come in at $274 per megawatt-hour

o_p 6y ago

This doesnt account the short duration of batteries, I have to replace them every time they go past their lifetime, so in the long term their cost is much higher

PeterisP 6y ago
The heavy machinery with moving parts lifting thousands and thousands of tons is also going to need maintenance and wear&tear replacements. The problem with scale is that all these proposed gravity batteries need much, much more machinery than an equivalent pumped capacity pumped hydro or chemical battery plant.
- polypodiopsi 6y ago
  Out of interest: do you have experience with mechanical engeneering or is this more of a common sense speculation?
- mplewis 6y ago
  This is something made easier by the fact that we understand how mechanical designs age. We've built high-standing structures with parts that move in a similar way that last decades. We understand how to maintain those structures without totally replacing them.

simion314 6y ago

You should finish reading or find a similar storage company that sells batteries and see how much they charge.

kurthr 6y ago

What you have described would last for 1000 days used to even out daily (solar) power demand/supply. So for a 25yr capability it would cost 8x more? I would hope not, and I think you could get 3000 cycles by restricting temperature and charge/discharge, but that still requires 2.5-3x higher cost and puts this solution as very competitive with current battery solutions.

choeger 6y ago
The cost was given purely in terms of MWh.

cheschire 6y ago

I wish that cost basis wasn't the only consideration when evaluating energy storage, but we're so accustomed to money being the great equalizer that things without a financial cost associated are often overlooked. What is the $/MWh cost associated with mining for, recycling, and disposing of battery components? What about the third order effects of centralizing control over the fuel source within only a handful of countries[0]? What's the $/MWh of the political shifts? I can't safely make assumptions about why you personally stopped reading after cost came up, but it seems to be a common reaction at this point. "Show me the money!" tends to end most conversations about energy these days. 0: https://unctad.org/news/demand-raw-materials-electric-car-batteries-set-rise-further https://unctad.org/news/demand-raw-materials-electric-car-ba...

darawk 6y ago
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.
- wizzwizz4 6y ago
  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.
  - darawk 6y ago
    Money is just a fungible unit of comparison for types of value, nothing more.
    - Qwertious 6y ago
      In that case, gas plants are the best peaker option in most places as in most place CO2 and methane emissions cost $0.

imtringued 6y ago

The only savings grace with these gravity systems is that they could last 100 years. Gravity is a very poor of storing energy. Height is limited by practicality. Reusing old mine shafts is just a code word for unaffordable. You need to increase the amount of mass that you move around, therefore your system should be infinitely scalable. By limiting yourself to mineshafts you have reduced the scalability option and the entire project becomes a scam.

billytetrud 6y ago

Car batteries don't last decades. Multiply that $100 by 5 years and you can see how the price racks up