6 ms·

MW is power, not energy

by zefr0g 2y ago

lysace 2y ago
> "In South Africa, for example, the total amount of energy produced from solar systems in 2019 was thought to be about 500 megawatts" This is annoyingly common with journalists and also a very clear tell that they don't have any idea what they are writing about. Maybe in a few years the writer will understand that it's tricky to store energy in a cost-efficient way and that energy isn't the same as power. Or perhaps they won't. Either way, in late 2024, this low level of understanding is pretty tiring. The writer "has been the the recipient of a 2017 National Association of Science Writers reporting award for coverage of air pollution in Detroit, and a finalist for the 2019 Livingston Award for a series on water politics at the Texas-Mexico border. At The Atlantic, she covers climate change." The writer's CV doesn't mention any education at all.
- dguest 2y ago
  It might not be complete nonsense. If you map energy -> power the paragraph actually says something sensible. It could have been worse: if they'd said something like "500 megawatts per week" it would be completely unclear what they even mean. Should you map it to megawatt-hours / week (around 3 MW), because that's a common (kind of goofy) unit to work in? Or does it mean they use (on average) 500 MW?
  - lysace 2y ago
    I admire your creativity/positivity!
- kragen 2y ago
  500 megawatts would be 4.4 terawatt hours per year. That's in the ballpark of what they actually did produce in 02019, according to https://en.wikipedia.org/wiki/Energy_in_South_Africa https://en.wikipedia.org/wiki/Energy_in_South_Africa. So the journalist seems to have actually been correct in this case, although it's a bit like saying "the distance covered by the runner was 12 miles per hour", when it would perhaps be more appropriate to say that that was the runner's speed rather than the runner's distance.
  - lysace 2y ago
    No-one claimed that any numbers were made up. Just that this was a very frequent and clear tell.
    - kragen 2y ago
      .
      - lysace 2y ago
        Edit: noticed that HN user kragen has replaced the comment I replied to with a dot, for some reason. This doesn't seem civil to me. You think it's clear tell that she knew what she was talking about when she wrote "the total amount of energy produced from solar systems in 2019 was thought to be about 500 megawatts". Similarly you think it's a clear tell that I don't know what I'm talking about when I say that this is an incorrect statement, and that this is a clear tell.
        kragen 2y ago
        Yes, because, as I explained above, I checked Wikipedia, and that figure turns out to be correct to within at worst a factor of two. Power units such as megawatts measure the rate at which energy is produced, consumed, or otherwise converted, which is to say, the amount of energy used per unit of time. For example, per year. A watt is about 31.6 megajoules per year. So there's nothing actually wrong with the reporter's statement, even though it would be more precise to say that the average power generated was thought to be around 500 megawatts.
        lysace 2y ago
        To summarize: The arithmetic number wasn't made up out of thin air. The unit (and arithmetic number) were wrong in the given context (energy). I claim that the latter is a common tell of a lack of understanding. You claim that I don't know what I'm talking about since the number wasn't made up.
- deleted 2y ago
  [deleted]
- EVa5I7bHFq9mnYK 2y ago
  Writers, and 99% of the people they write for, don't care about the difference between MW and MWh, bit and byte, or million and billion.
  - 0cf8612b2e1e 2y ago
    Agreed, it would be great if everything could always be technically accurate, but like fetch, it is never going to happen. It is wrong basically everywhere. Which is understandable as common vernacular readily interchanges energy and power.
  - lysace 2y ago
    I kind of want a "science journalist" "specializing in the climate change field" to understand the difference. Understanding the difference between power and energy is really the most crucial aspect you can imagine, here. Still they keep failing at this.
    - kragen 2y ago
      But in this case what was being discussed was the rate at which South Africa converted solar energy into electrical energy, which is a power, and the journalist correctly used units of power. Many journalists are indeed staggeringly incompetent, but in this case you are the one who is mistaken.
fsckboy 2y ago
>MW is power, not energy i think a more useful correction for people whose day to day lives don't require them to keep track of the difference is MW is rate of energy use with respect to time, not total energy. The rate of energy in science is called "power" because they both are measures of energy, and the energy/power distinction in science co-opted preexisting words that didn't have those precise meanings. Total energy is the integral of power over time, so it's not really wrong to say "this higher energy battery contains more power" in everyday speech.
ikesau 2y ago
And MW wasn't even the unit used in the source, the SAPVIA Solar PV Dashboard[1], which shows Megawatt Peak. MWp is a unit that refers to the theoretical maximum power output of a solar PV system (e.g. under ideal conditions.) These data accord with the article's thesis, but it doesn't inspire confidence that units were conflated. They're not the same thing as megawatts, they don't measure energy, etc. [1] https://sapvia.co.za/dataportal/dataportal-public https://sapvia.co.za/dataportal/dataportal-public

MW is power, not energy

by zefr0g 2y ago

MW is power, not energy

> "In South Africa, for example, the total amount of energy produced from solar systems in 2019 was thought to be about 500 megawatts" This is annoyingly common with journalists and also a very clear tell that they don't have any idea what they are writing about. Maybe in a few years the writer will understand that it's tricky to store energy in a cost-efficient way and that energy isn't the same as power. Or perhaps they won't. Either way, in late 2024, this low level of understanding is pretty tiring. The writer "has been the the recipient of a 2017 National Association of Science Writers reporting award for coverage of air pollution in Detroit, and a finalist for the 2019 Livingston Award for a series on water politics at the Texas-Mexico border. At The Atlantic, she covers climate change." The writer's CV doesn't mention any education at all.

dguest 2y ago
It might not be complete nonsense. If you map energy -> power the paragraph actually says something sensible. It could have been worse: if they'd said something like "500 megawatts per week" it would be completely unclear what they even mean. Should you map it to megawatt-hours / week (around 3 MW), because that's a common (kind of goofy) unit to work in? Or does it mean they use (on average) 500 MW?
- lysace 2y ago
  I admire your creativity/positivity!
kragen 2y ago
500 megawatts would be 4.4 terawatt hours per year. That's in the ballpark of what they actually did produce in 02019, according to https://en.wikipedia.org/wiki/Energy_in_South_Africa https://en.wikipedia.org/wiki/Energy_in_South_Africa. So the journalist seems to have actually been correct in this case, although it's a bit like saying "the distance covered by the runner was 12 miles per hour", when it would perhaps be more appropriate to say that that was the runner's speed rather than the runner's distance.
- lysace 2y ago
  No-one claimed that any numbers were made up. Just that this was a very frequent and clear tell.
  - kragen 2y ago
    .
    - lysace 2y ago
      Edit: noticed that HN user kragen has replaced the comment I replied to with a dot, for some reason. This doesn't seem civil to me. You think it's clear tell that she knew what she was talking about when she wrote "the total amount of energy produced from solar systems in 2019 was thought to be about 500 megawatts". Similarly you think it's a clear tell that I don't know what I'm talking about when I say that this is an incorrect statement, and that this is a clear tell.
      - kragen 2y ago
        Yes, because, as I explained above, I checked Wikipedia, and that figure turns out to be correct to within at worst a factor of two. Power units such as megawatts measure the rate at which energy is produced, consumed, or otherwise converted, which is to say, the amount of energy used per unit of time. For example, per year. A watt is about 31.6 megajoules per year. So there's nothing actually wrong with the reporter's statement, even though it would be more precise to say that the average power generated was thought to be around 500 megawatts.
        lysace 2y ago
        To summarize: The arithmetic number wasn't made up out of thin air. The unit (and arithmetic number) were wrong in the given context (energy). I claim that the latter is a common tell of a lack of understanding. You claim that I don't know what I'm talking about since the number wasn't made up.
deleted 2y ago
[deleted]
EVa5I7bHFq9mnYK 2y ago
Writers, and 99% of the people they write for, don't care about the difference between MW and MWh, bit and byte, or million and billion.
- 0cf8612b2e1e 2y ago
  Agreed, it would be great if everything could always be technically accurate, but like fetch, it is never going to happen. It is wrong basically everywhere. Which is understandable as common vernacular readily interchanges energy and power.
- lysace 2y ago
  I kind of want a "science journalist" "specializing in the climate change field" to understand the difference. Understanding the difference between power and energy is really the most crucial aspect you can imagine, here. Still they keep failing at this.
  - kragen 2y ago
    But in this case what was being discussed was the rate at which South Africa converted solar energy into electrical energy, which is a power, and the journalist correctly used units of power. Many journalists are indeed staggeringly incompetent, but in this case you are the one who is mistaken.

fsckboy 2y ago

>MW is power, not energy i think a more useful correction for people whose day to day lives don't require them to keep track of the difference is MW is rate of energy use with respect to time, not total energy. The rate of energy in science is called "power" because they both are measures of energy, and the energy/power distinction in science co-opted preexisting words that didn't have those precise meanings. Total energy is the integral of power over time, so it's not really wrong to say "this higher energy battery contains more power" in everyday speech.

ikesau 2y ago

And MW wasn't even the unit used in the source, the SAPVIA Solar PV Dashboard[1], which shows Megawatt Peak. MWp is a unit that refers to the theoretical maximum power output of a solar PV system (e.g. under ideal conditions.) These data accord with the article's thesis, but it doesn't inspire confidence that units were conflated. They're not the same thing as megawatts, they don't measure energy, etc. [1] https://sapvia.co.za/dataportal/dataportal-public https://sapvia.co.za/dataportal/dataportal-public