3 ms·

Sure but wouldn’t we need to mine exponentially less uranium? How many tons of neodymium need to be mined for wind turbines to produce the equivalent output of

Sure but wouldn’t we need to mine exponentially less uranium? How many tons of neodymium need to be mined for wind turbines to produce the equivalent output of a nuclear reactor, for example.

dane-pgp 5y ago
That's an interesting question, actually, and the numbers seem difficult to come by. A master's thesis from 2011 says[0]: "data on the amount of rare earths in wind turbines vary, ranging from 0.2 to 3.3 kg of neodymium content per kW of rated capacity" For comparison, a nuclear power station generates[1]: "24,000,000 kWh from 1 kg of uranium-235" So, taking the lower estimate for the neodymium content, the wind turbine would have to produce energy for 0.2 x 24,000,000 hours to be as efficient in terms of mass. That's about 548 years. Even with recycling, that's a longer term commitment than some nuclear waste storage proposals, although with less of a proliferation risk. [0] https://core.ac.uk/download/pdf/153229259.pdf https://core.ac.uk/download/pdf/153229259.pdf [1] https://www.euronuclear.org/glossary/fuel-comparison/ https://www.euronuclear.org/glossary/fuel-comparison/
- fsh 5y ago
  235U may have an impressive energy density, but uranium ore contains very little natural uranium and natural uranium contains very little 235U. According to this back-of-the-envelope calculation [1], a typical energy density of uranium ore is only around 1400 MJ/kg, so only 60 times higher than that of coal. [1] http://www.plux.co.uk/energy-density-of-uranium/ http://www.plux.co.uk/energy-density-of-uranium/
  - dane-pgp 5y ago
    To convert that into the (slightly more clumsy) units of my post above, 1400 MJ is about 390 kWh (which is a lot smaller than 24 million). Even taking the upper estimate of neodymium content then, 3.3 x 390 hours is only 54 days. I don't know how much ore needs to be dug up to extract 1 kg of neodymium, but one site boasts 7% rare earth content in the material it processes[0] so there might need to be a 14x scale factor to avoid comparing apples to ore ranges. 54 days x 14 is 2 years, which should be well under the average life time of a turbine, even before recycling is taken into account. We do have to also consider the capacity factor of wind turbines, though (not just their rated capacity), which "range from 0.26 to 0.52" according to a recent factsheet[1], so that might bump the estimate to 8 years. [0] https://mpmaterials.com/what-we-do/ https://mpmaterials.com/what-we-do/ [1] https://css.umich.edu/factsheets/wind-energy-factsheet https://css.umich.edu/factsheets/wind-energy-factsheet

Sure but wouldn’t we need to mine exponentially less uranium? How many tons of neodymium need to be mined for wind turbines to produce the equivalent output of a nuclear reactor, for example.

dane-pgp 5y ago

That's an interesting question, actually, and the numbers seem difficult to come by. A master's thesis from 2011 says[0]: "data on the amount of rare earths in wind turbines vary, ranging from 0.2 to 3.3 kg of neodymium content per kW of rated capacity" For comparison, a nuclear power station generates[1]: "24,000,000 kWh from 1 kg of uranium-235" So, taking the lower estimate for the neodymium content, the wind turbine would have to produce energy for 0.2 x 24,000,000 hours to be as efficient in terms of mass. That's about 548 years. Even with recycling, that's a longer term commitment than some nuclear waste storage proposals, although with less of a proliferation risk. [0] https://core.ac.uk/download/pdf/153229259.pdf https://core.ac.uk/download/pdf/153229259.pdf [1] https://www.euronuclear.org/glossary/fuel-comparison/ https://www.euronuclear.org/glossary/fuel-comparison/

fsh 5y ago
235U may have an impressive energy density, but uranium ore contains very little natural uranium and natural uranium contains very little 235U. According to this back-of-the-envelope calculation [1], a typical energy density of uranium ore is only around 1400 MJ/kg, so only 60 times higher than that of coal. [1] http://www.plux.co.uk/energy-density-of-uranium/ http://www.plux.co.uk/energy-density-of-uranium/
- dane-pgp 5y ago
  To convert that into the (slightly more clumsy) units of my post above, 1400 MJ is about 390 kWh (which is a lot smaller than 24 million). Even taking the upper estimate of neodymium content then, 3.3 x 390 hours is only 54 days. I don't know how much ore needs to be dug up to extract 1 kg of neodymium, but one site boasts 7% rare earth content in the material it processes[0] so there might need to be a 14x scale factor to avoid comparing apples to ore ranges. 54 days x 14 is 2 years, which should be well under the average life time of a turbine, even before recycling is taken into account. We do have to also consider the capacity factor of wind turbines, though (not just their rated capacity), which "range from 0.26 to 0.52" according to a recent factsheet[1], so that might bump the estimate to 8 years. [0] https://mpmaterials.com/what-we-do/ https://mpmaterials.com/what-we-do/ [1] https://css.umich.edu/factsheets/wind-energy-factsheet https://css.umich.edu/factsheets/wind-energy-factsheet