5 ms·

Could explain why it’s “bullshit?”

pfdietz 4y ago
The person I was responding to qualified with "* Or maybe a country with a very small population and a lot of unused land maybe which is a pretty small category." But if you actually do the arithmetic, you will find that land constraints are not important for most countries. There's plenty of land for most countries to produce what they need (as long as they don't do something braindead like trying to burn biomass). Put it another way: the value of the energy generated per area of land is much greater than the value produced by other uses of the land, like agriculture or forestry, and no one claims those are infeasible. I believe this wrong belief about renewables not being able to do the job came from the assumption that large amounts of biofuel would be needed (IIRC MacKay's "Sustainable Energy Without the Hot Air" made this mistake). The efficiency of sunlight => fuel from growth of biomass is very low.
- epups 4y ago
  I agree land use is not a major consideration here. But what about base load? You cannot guarantee proper weather and we currently don't have anywhere near battery capacity to store energy from renewable sources for a meaningful amount of time. So ultimately yes, you are faced with a choice between hydro, coal/gas and nuclear for that.
  - pfdietz 4y ago
    Take the mismatch between solar/wind and demand. Take the Fourier transform of this mismatch. It has components at various frequencies. There are various storage technologies that are best for various frequencies: batteries for high frequences (diurnal or faster); maybe thermal storage for intermediate frequencies (days to weeks); maybe hydrogen for low frequencies (months, yearly, or even longer). If you optimize the system with the right combination of solar/wind (which are typically somewhat anticorrelated, or at least somewhat independent), and various kinds of storage, you can generate an artificial steady output for not that much. See https://model.energy/ https://model.energy/ for a web site that generates cost optimal (under various cost assumptions and using historical weather data) solutions to this problem in various places.
    - epups 4y ago
      None of these storage technologies are currently being used at scale. Not a single country is relying on batteries or hydrogen to solve the problem I mentioned above.
      - pfdietz 4y ago
        Ah, the good old "if it hasn't happened yet, it can't ever happen" argument. Priceless. Remember, we're talking about a claim that renewables are fundamentally blocked from providing the power for the grid in most countries. If you exclude the possibility of additional foreseeable technological development, then nuclear also fails, since existing commercial reactors very quickly exhaust the available economical uranium if they are asked to power the world.
        epups 4y ago
        Your statement about uranium is incorrect for a couple of reasons, but that's beside the point. You're asking us to take a leap of faith and believe in experimental technologies that have not been proven to work at scale at all. I'm not denying they might work one day, and I'm all for investing in them to see if they do. But in the meantime, hundreds of thousands of people will die due to switching to coal reactors. This is a concrete fact that is happening today. We have a safe energy source in nuclear, and we should make use of it to avoid these real, measurable, tangible consequences.
        pfdietz 4y ago
        CANDU reactors may be an exception, since they can operate with a conversion ratio of nearly 1 (about 0.9, IIRC, which will extend the uranium concentration by an order of magnitude). But breeders are not currently commercial reactors -- there have been prototypes, but they are not commercial. Nor is seawater uranium extraction commercially demonstrated (it's not even ready for that; the resins have too short a lifespan, for one thing).
        pyuser583 4y ago

The person I was responding to qualified with "* Or maybe a country with a very small population and a lot of unused land maybe which is a pretty small category." But if you actually do the arithmetic, you will find that land constraints are not important for most countries. There's plenty of land for most countries to produce what they need (as long as they don't do something braindead like trying to burn biomass). Put it another way: the value of the energy generated per area of land is much greater than the value produced by other uses of the land, like agriculture or forestry, and no one claims those are infeasible. I believe this wrong belief about renewables not being able to do the job came from the assumption that large amounts of biofuel would be needed (IIRC MacKay's "Sustainable Energy Without the Hot Air" made this mistake). The efficiency of sunlight => fuel from growth of biomass is very low.

epups 4y ago
I agree land use is not a major consideration here. But what about base load? You cannot guarantee proper weather and we currently don't have anywhere near battery capacity to store energy from renewable sources for a meaningful amount of time. So ultimately yes, you are faced with a choice between hydro, coal/gas and nuclear for that.
- pfdietz 4y ago
  Take the mismatch between solar/wind and demand. Take the Fourier transform of this mismatch. It has components at various frequencies. There are various storage technologies that are best for various frequencies: batteries for high frequences (diurnal or faster); maybe thermal storage for intermediate frequencies (days to weeks); maybe hydrogen for low frequencies (months, yearly, or even longer). If you optimize the system with the right combination of solar/wind (which are typically somewhat anticorrelated, or at least somewhat independent), and various kinds of storage, you can generate an artificial steady output for not that much. See https://model.energy/ https://model.energy/ for a web site that generates cost optimal (under various cost assumptions and using historical weather data) solutions to this problem in various places.
  - epups 4y ago
    None of these storage technologies are currently being used at scale. Not a single country is relying on batteries or hydrogen to solve the problem I mentioned above.
    - pfdietz 4y ago
      Ah, the good old "if it hasn't happened yet, it can't ever happen" argument. Priceless. Remember, we're talking about a claim that renewables are fundamentally blocked from providing the power for the grid in most countries. If you exclude the possibility of additional foreseeable technological development, then nuclear also fails, since existing commercial reactors very quickly exhaust the available economical uranium if they are asked to power the world.
      - epups 4y ago
        Your statement about uranium is incorrect for a couple of reasons, but that's beside the point. You're asking us to take a leap of faith and believe in experimental technologies that have not been proven to work at scale at all. I'm not denying they might work one day, and I'm all for investing in them to see if they do. But in the meantime, hundreds of thousands of people will die due to switching to coal reactors. This is a concrete fact that is happening today. We have a safe energy source in nuclear, and we should make use of it to avoid these real, measurable, tangible consequences.
        pfdietz 4y ago
        CANDU reactors may be an exception, since they can operate with a conversion ratio of nearly 1 (about 0.9, IIRC, which will extend the uranium concentration by an order of magnitude). But breeders are not currently commercial reactors -- there have been prototypes, but they are not commercial. Nor is seawater uranium extraction commercially demonstrated (it's not even ready for that; the resins have too short a lifespan, for one thing).
      - pyuser583 4y ago