3 ms·

Managing a hot molten salt pool is not as difficult as trying to deal with many lithium cells. You mention dropping cargo containers on site, but that is not t

by nickff 11y ago

Managing a hot molten salt pool is not as difficult as trying to deal with many lithium cells. You mention dropping cargo containers on site, but that is not the whole problem; you need to manufacture these containers and have a way of continuously monitoring the cells, either finding and isolating the 'bad' ones, or replacing whole containers. In addition, the molten salt will last far more cycles than the batteries, while costing less to replace and being simpler to service.

toomuchtodo 11y ago
https://www.teslamotors.com/powerpack https://www.teslamotors.com/powerpack That's the benefit though, right? I can write Tesla a check and they can ship me an entire utility scale energy storage system by rail/truck multi-modal. I can't do that with molten salt.
- nickff 11y ago
  You are vastly underestimating the cost and complexity of running this system at an affordable cost. You would end up with Tesla running the majority of your facility (by cost), and consequently would not be a competitive plant. Let's do some simple math: An average natural gas plant seems to be around 800MW, and we might assume that they are running somewhere around 1/2 capacity when there is not much solar irradiation (evening and night), giving us an average power level of 400MW. Wikipedia says that Lithium Ion cells have a specific energy of about 100-240 W.h/kg, and I'll assume that Tesla uses some good 200W.h/kg cells. If the plant has to run with no irradiation for 10 hours at half capacity, it needs 4000 MW.h of energy in batteries, which is 4000M/200 = 20Mkg of batteries not including any losses during discharge or wasted energy for cooling. 20 million kilograms of batteries would be very expensive to store and maintain; they would also take up a lot of containers. A 20' container is usually maxed out at about 20 tons, so you would need a thousand of them. The basic problem is that unlike molten salt, there are no economies of scale to be had with batteries or photovoltaic panels.
  - Retric 11y ago
    There is no need for Li-Ion for grid storage as weight is a non issue it's just a question of cost. Don't forget we ship train loads of coal across several states just to burn it.
    - nickff 11y ago
      I mentioned weight to give some idea of the amount of batteries that would be required, and how many containers would be needed (as I was responding to a suggestion of using containerized batteries), not because the weight is a significant factor.

by nickff 11y ago

toomuchtodo 11y ago

https://www.teslamotors.com/powerpack https://www.teslamotors.com/powerpack That's the benefit though, right? I can write Tesla a check and they can ship me an entire utility scale energy storage system by rail/truck multi-modal. I can't do that with molten salt.

nickff 11y ago
You are vastly underestimating the cost and complexity of running this system at an affordable cost. You would end up with Tesla running the majority of your facility (by cost), and consequently would not be a competitive plant. Let's do some simple math: An average natural gas plant seems to be around 800MW, and we might assume that they are running somewhere around 1/2 capacity when there is not much solar irradiation (evening and night), giving us an average power level of 400MW. Wikipedia says that Lithium Ion cells have a specific energy of about 100-240 W.h/kg, and I'll assume that Tesla uses some good 200W.h/kg cells. If the plant has to run with no irradiation for 10 hours at half capacity, it needs 4000 MW.h of energy in batteries, which is 4000M/200 = 20Mkg of batteries not including any losses during discharge or wasted energy for cooling. 20 million kilograms of batteries would be very expensive to store and maintain; they would also take up a lot of containers. A 20' container is usually maxed out at about 20 tons, so you would need a thousand of them. The basic problem is that unlike molten salt, there are no economies of scale to be had with batteries or photovoltaic panels.
- Retric 11y ago
  There is no need for Li-Ion for grid storage as weight is a non issue it's just a question of cost. Don't forget we ship train loads of coal across several states just to burn it.
  - nickff 11y ago
    I mentioned weight to give some idea of the amount of batteries that would be required, and how many containers would be needed (as I was responding to a suggestion of using containerized batteries), not because the weight is a significant factor.