4 ms·

In how much time does a solar/wind project becomes carbon negative compared to coal?

realusername 3y ago
It never becomes carbon negative? It just emits less overall. To become carbon negative it would have to suck carbon back from the air.
- balderdash 3y ago
  I think they meant how many years until break even vs conventional alternatives
  - culi 3y ago
    Again, what is "break even"? For example, in electric vehicles, the initial production emits much more than a conventional gas car (mostly due to the battery). A lot of people don't realize that as much as 30% of a vehicle's lifetime emissions can be in the initial production alone. As a result it takes ~28-68.2k miles (in the US) for an EV to emit comparatively fewer emissions Are you looking for a number like that? If you are then you would have to more narrowly defined your use-case. There are far too many factors, infrastructures, conditions, technologies, etc to consider
    - blacksmith_tb 3y ago
      Those numbers seem much too high, for example the projection for a Model 3 is that you'd only need to drive it 13K mi / 22K km[1] 1: https://www.reuters.com/business/autos-transportation/lifetime-carbon-emissions-electric-vehicles-vs-gasoline-cars-2021-06-29/ https://www.reuters.com/business/autos-transportation/lifeti...
      - culi 3y ago
        My numbers come from a study published in Nature in 2022: https://www.nature.com/articles/s41893-022-00862-3 https://www.nature.com/articles/s41893-022-00862-3 The Argonne model relied on in the article you linked is quite dated at this point and has its limitations (which are acknowledged by the authors of it themselves).
        blacksmith_tb 3y ago
        I see, so that 28K number looks solid, the 68K upper bound applies to a scenario where someone doesn't switch to an EV but buys one and still keeps driving an ICE vehicle too, which seems odd - I would think many drivers could use an EV for all their shorter trips (certainly shopping, likely commuting), but paying to register/license an extra car just for the occasional long trip doesn't seem very practical.
        culi 3y ago
        That's a fair take. As stated in the study that scenario is based around actual documented EV usage behavior amongst owners PS, cheers for actually reading the paper
    - realusername 3y ago
      > As a result it takes ~28-68.2k miles (in the US) for an EV to emit comparatively fewer emissions That's really not much to be honest and the US doesn't exactly have the best grid in the world in terms of carbon either.
      - culi 3y ago
        Yeah I don't think it's that much either. I feel a lot of readers are reading my comments as if I'm being hostile towards renewables and downvoting me because of that assumption. I am not opposed to renewables, nor am I trying to argue that "it takes [insert amount of miles that's well within the average lifespan of a car] for EVs to break even" somehow implies "EVs bad" Obviously I don't support the continued usage of oil and coal as energy resources
mitthrowaway2 3y ago
Negative compared to a preexisting coal plant? It's probably a matter of weeks.
- _justinfunk 3y ago
  Note that it takes 2 orders of magnitude more wind turbines to replace that preexisting coal plant. (i.e. >100 turbines for 1 coal plant)
  - mitthrowaway2 3y ago
    Yes, that's factored in. The average coal plant outputs 830 MW, and obviously nobody is building wind turbines that large. That's why wind power installations are called "wind farms".
oezi 3y ago
The figure I recently read was that solar panels are recouping their manufacturing carbon impact in less than a year when compared to conventional fossil mix.

It never becomes carbon negative? It just emits less overall. To become carbon negative it would have to suck carbon back from the air.

balderdash 3y ago
I think they meant how many years until break even vs conventional alternatives
- culi 3y ago
  Again, what is "break even"? For example, in electric vehicles, the initial production emits much more than a conventional gas car (mostly due to the battery). A lot of people don't realize that as much as 30% of a vehicle's lifetime emissions can be in the initial production alone. As a result it takes ~28-68.2k miles (in the US) for an EV to emit comparatively fewer emissions Are you looking for a number like that? If you are then you would have to more narrowly defined your use-case. There are far too many factors, infrastructures, conditions, technologies, etc to consider
  - blacksmith_tb 3y ago
    Those numbers seem much too high, for example the projection for a Model 3 is that you'd only need to drive it 13K mi / 22K km[1] 1: https://www.reuters.com/business/autos-transportation/lifetime-carbon-emissions-electric-vehicles-vs-gasoline-cars-2021-06-29/ https://www.reuters.com/business/autos-transportation/lifeti...
    - culi 3y ago
      My numbers come from a study published in Nature in 2022: https://www.nature.com/articles/s41893-022-00862-3 https://www.nature.com/articles/s41893-022-00862-3 The Argonne model relied on in the article you linked is quite dated at this point and has its limitations (which are acknowledged by the authors of it themselves).
      - blacksmith_tb 3y ago
        I see, so that 28K number looks solid, the 68K upper bound applies to a scenario where someone doesn't switch to an EV but buys one and still keeps driving an ICE vehicle too, which seems odd - I would think many drivers could use an EV for all their shorter trips (certainly shopping, likely commuting), but paying to register/license an extra car just for the occasional long trip doesn't seem very practical.
        culi 3y ago
        That's a fair take. As stated in the study that scenario is based around actual documented EV usage behavior amongst owners PS, cheers for actually reading the paper
  - realusername 3y ago
    > As a result it takes ~28-68.2k miles (in the US) for an EV to emit comparatively fewer emissions That's really not much to be honest and the US doesn't exactly have the best grid in the world in terms of carbon either.
    - culi 3y ago
      Yeah I don't think it's that much either. I feel a lot of readers are reading my comments as if I'm being hostile towards renewables and downvoting me because of that assumption. I am not opposed to renewables, nor am I trying to argue that "it takes [insert amount of miles that's well within the average lifespan of a car] for EVs to break even" somehow implies "EVs bad" Obviously I don't support the continued usage of oil and coal as energy resources

mitthrowaway2 3y ago

Negative compared to a preexisting coal plant? It's probably a matter of weeks.

_justinfunk 3y ago
Note that it takes 2 orders of magnitude more wind turbines to replace that preexisting coal plant. (i.e. >100 turbines for 1 coal plant)
- mitthrowaway2 3y ago
  Yes, that's factored in. The average coal plant outputs 830 MW, and obviously nobody is building wind turbines that large. That's why wind power installations are called "wind farms".

oezi 3y ago

The figure I recently read was that solar panels are recouping their manufacturing carbon impact in less than a year when compared to conventional fossil mix.