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Previous thread: https://news.ycombinator.com/item?id=7847829 https://news.ycombinator.com/item?id=7847829 This is not a very green technology. It is not the s

by abalone 12y ago

Previous thread: https://news.ycombinator.com/item?id=7847829 https://news.ycombinator.com/item?id=7847829 This is not a very green technology. It is not the same as recycling aluminum. The aluminum is turned back into alumina by the reaction. "Recharging" this "battery" (it's more of a fuel cell) means shipping a 220lb module back to a far-away aluminum smelter and reforging it anew. Forging aluminum is a hugely energy intensive process that produces significant greenhouse gases. It's a cheat to say the smelters use hydropower -- if this were to scale up to power the automotive industry it would require more dams which have major ecological impact. Plus there's still the greenhouse gas emission and transport problem.

gus_massa 12y ago
> It is not the same as recycling aluminum. The aluminum is turned back into alumina by the reaction. I agree. Recycling an aluminum can use much less energy than converting the aluminum oxide to metallic aluminum (perhaps only a 10%). To convert the aluminum salts of one of these used batteries to a new battery you need to reduce again the aluminum to the metallic state, so you need almost all the original energy (perhaps only the 90% because you may skip a few purifying steps). > It's a cheat to say the smelters use hydropower [...] I disagree here. To move any car you need energy. The energy can come form gasoline, gas, a battery, ... In all the electric cars the battery have to be recharged. In a normal electric car (for example a Tesla) you charge the battery every night at home. This aluminum battery is “recharged” in the smelters only a few times in a year. In both cases the energy from the recharge comes from oil, gas, solar, wind turbines, nuclear, hydroelectric or whatever is cheaper there. If both model have the same efficiency, then doing a lot of small recharges is as green as doing one big “recharge”.
AlisdairO 12y ago
This still has the potential to be quite green, despite CO2 in the manufacturing process. When combined with a Li-ion pack for regular journeys, the average driver isn't going to be using the Al-O2 battery very much. Our current solutions to range issues are packaging a shit-ton of li-ion capacity (model s), or including a separate engine (volt). These both add enormous weight and manufacturing costs to the car. The much higher energy density of this solution means that you carry a lot less weight with you during most of your journeys. Let's say that these guys' estimates hold up, and the average driver does < 2000 miles in long distance journeys out of a total of, say, 12000 miles per year. How much difference in total energy consumption will shaving 200kg (lose 300kg for 2/3rds of the tesla's battery pack, gain 100kg for the new al-o2 pack) off the weight of the car make? edit: I realise this is rather hand-wavy, considering the 1800 mile range for this system is based off a smaller car than the model s, but I still think it's worth considering the difference in overall energy consumption that the higher energy density of this pack provides.
- lloeki 12y ago
  > a smaller car For reference, this is a Citroën C1 or Peugeot 107 (same car as Toyota Aygo, albeit with a slightly different design) [0]: http://en.wikipedia.org/wiki/Citroën_C1 http://en.wikipedia.org/wiki/Citroën_C1
- stonemetal 12y ago
  > 1800 mile range for this system It is 1800KM, which is closer to 1000 than 2000 miles. At 12000 miles a year that is about a battery a month rather than a battery every other month.
  - AlisdairO 12y ago
    They're claiming that it has a max range of 1860 miles for a 100kg battery system: > The Phinergy aluminum-air battery at 100 kilograms (220 pounds) weight contained enough on board energy to allow the vehicle to travel up to 3,000 kilometers (over 1,860 miles) The article does seem slightly unclear on that point, though. Again, if you have normal driving patterns this Al-O2 system is a backup battery. You'd be using a smaller li-ion battery for the day-to-day drives. That means a normal user wouldn't need a new Al-O2 battery every month, because they'd only rarely be using it.
Elv13 12y ago
In Québec (where those batteries would be recharged), if we need more dams we build more dams. The only limiting factor is the demand and the amount of legal nightmare we are ready to unleash by flooding the first nation land. In both case, money is usually the answer. A single river can support tens of dams as long as the flow is correctly regulated. Moving that power to the states (2000km) is wasting 70% of the power in losses. Better build more smelters in the north and ship the energy as battery instead.
rwallace 12y ago
It's true that smelting aluminium is a hugely energy intensive process, but it can use energy wherever and whenever it's available. That's actually a much bigger deal than it sounds like, because the biggest hassle with solar and wind - the best forms of renewable energy we have, if nuclear is politically impossible - is bridging the gap in time and space between availability of the energy and people wanting to use it. If we start being able to store energy in the form of aluminum, that would be great. Put the aluminum plant in the desert next to however many hectares of solar panels, let it spend all day soaking up solar energy, no need for power grid upgrades.

by abalone 12y ago

gus_massa 12y ago

> It is not the same as recycling aluminum. The aluminum is turned back into alumina by the reaction. I agree. Recycling an aluminum can use much less energy than converting the aluminum oxide to metallic aluminum (perhaps only a 10%). To convert the aluminum salts of one of these used batteries to a new battery you need to reduce again the aluminum to the metallic state, so you need almost all the original energy (perhaps only the 90% because you may skip a few purifying steps). > It's a cheat to say the smelters use hydropower [...] I disagree here. To move any car you need energy. The energy can come form gasoline, gas, a battery, ... In all the electric cars the battery have to be recharged. In a normal electric car (for example a Tesla) you charge the battery every night at home. This aluminum battery is “recharged” in the smelters only a few times in a year. In both cases the energy from the recharge comes from oil, gas, solar, wind turbines, nuclear, hydroelectric or whatever is cheaper there. If both model have the same efficiency, then doing a lot of small recharges is as green as doing one big “recharge”.

AlisdairO 12y ago

This still has the potential to be quite green, despite CO2 in the manufacturing process. When combined with a Li-ion pack for regular journeys, the average driver isn't going to be using the Al-O2 battery very much. Our current solutions to range issues are packaging a shit-ton of li-ion capacity (model s), or including a separate engine (volt). These both add enormous weight and manufacturing costs to the car. The much higher energy density of this solution means that you carry a lot less weight with you during most of your journeys. Let's say that these guys' estimates hold up, and the average driver does < 2000 miles in long distance journeys out of a total of, say, 12000 miles per year. How much difference in total energy consumption will shaving 200kg (lose 300kg for 2/3rds of the tesla's battery pack, gain 100kg for the new al-o2 pack) off the weight of the car make? edit: I realise this is rather hand-wavy, considering the 1800 mile range for this system is based off a smaller car than the model s, but I still think it's worth considering the difference in overall energy consumption that the higher energy density of this pack provides.

lloeki 12y ago
> a smaller car For reference, this is a Citroën C1 or Peugeot 107 (same car as Toyota Aygo, albeit with a slightly different design) [0]: http://en.wikipedia.org/wiki/Citroën_C1 http://en.wikipedia.org/wiki/Citroën_C1
stonemetal 12y ago
> 1800 mile range for this system It is 1800KM, which is closer to 1000 than 2000 miles. At 12000 miles a year that is about a battery a month rather than a battery every other month.
- AlisdairO 12y ago
  They're claiming that it has a max range of 1860 miles for a 100kg battery system: > The Phinergy aluminum-air battery at 100 kilograms (220 pounds) weight contained enough on board energy to allow the vehicle to travel up to 3,000 kilometers (over 1,860 miles) The article does seem slightly unclear on that point, though. Again, if you have normal driving patterns this Al-O2 system is a backup battery. You'd be using a smaller li-ion battery for the day-to-day drives. That means a normal user wouldn't need a new Al-O2 battery every month, because they'd only rarely be using it.

Elv13 12y ago

In Québec (where those batteries would be recharged), if we need more dams we build more dams. The only limiting factor is the demand and the amount of legal nightmare we are ready to unleash by flooding the first nation land. In both case, money is usually the answer. A single river can support tens of dams as long as the flow is correctly regulated. Moving that power to the states (2000km) is wasting 70% of the power in losses. Better build more smelters in the north and ship the energy as battery instead.

rwallace 12y ago

It's true that smelting aluminium is a hugely energy intensive process, but it can use energy wherever and whenever it's available. That's actually a much bigger deal than it sounds like, because the biggest hassle with solar and wind - the best forms of renewable energy we have, if nuclear is politically impossible - is bridging the gap in time and space between availability of the energy and people wanting to use it. If we start being able to store energy in the form of aluminum, that would be great. Put the aluminum plant in the desert next to however many hectares of solar panels, let it spend all day soaking up solar energy, no need for power grid upgrades.