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From the language of the article it's somewhat ambiguous. "A capacity factor of 100 percent means the wind farm would be sending 30MW of power to the grid ever

From the language of the article it's somewhat ambiguous. "A capacity factor of 100 percent means the wind farm would be sending 30MW of power to the grid every minute of every day since it's been in operation." The "sending" portion makes me interpret this in the sense of 30MW per minute.

cbcoutinho 9y ago
Most renewable energy sources are variable, meaning they have a capacity/load factor that is less than 100% - you would never mention the load factor of a natural gas power plant because it's essentially a turnkey solution that doesn't fluctuate. Renewable energy is different, and it's good that this issue is mentioned in articles so that it's acknowledged as being a challenge. I don't think it's ambiguous in any way
- ChuckMcM 9y ago
  > ... you would never mention the load factor of a natural gas power plant because it's essentially a turnkey solution that doesn't fluctuate. As I understood the term the capacity factor is the percentage of time the plant is generating power. All plants have periods of maintenance and other "down times" which means they don't achieve 100% capacity. I would expect to use that number like this: Given a 30MW plant with a 50% capacity factor measured for the year, I would consider it to provide 30MW x 180 x 24 or 129,600 MWh of generating capacity. Two plants with a 50% capacity factor would give you coverage at their rated power all year only if they never overlapped in their down time. So if I was working the issue operationally I'd put in three plants to insure I had 100% coverage of 30MW all year long.
  - cbcoutinho 9y ago
    Maintenance does incur planned downtime on a power plant, but those things can be planned for when there isn't much energy usage throughout the year. In colder climates that's usually in the spring/summer. If a plant goes out for two weeks every year for maintenance, that's not a big problem. A wind farm on the other hand has a much lower load factor (UK offshore is around 30% [0]), and that load capacity isn't planned at all. You might get 30% on average per year, but that daily capacity fluctuates throughout the year - that's what I mean about fluctuating capacity. [0] https://www.gov.uk/government/statistics/renewable-sources-of-energy-chapter-6-digest-of-united-kingdom-energy-statistics-dukes https://www.gov.uk/government/statistics/renewable-sources-o...
stephen_g 9y ago
It's badly worded, but most people should get the meaning in context of talking about capacity factor. "Every minute of every day" is just a common English expression to mean "all the time." The word "minute" in there isn't significant and doesn't factor in the calculation, it's just for emphasis. So really all the author means is "producing 30MW consistently for the whole time it's been in operation." Or if they did use minutes as a time slice in the capacity calculation, it would have to be "averaging 30MW during every minute of every day".
epistasis 9y ago
When there's a potential ambiguity and one meaning is sensical and the other nonsensical, that's not actually an ambiguity. Saying that this is ambiguous is paramount to making the assumption that the author does not know the difference, and then trying to twist the meanings to prove your point. That's unnecessarily tendentious.
- bthornbury 9y ago
  Precision of language is important.

cbcoutinho 9y ago

Most renewable energy sources are variable, meaning they have a capacity/load factor that is less than 100% - you would never mention the load factor of a natural gas power plant because it's essentially a turnkey solution that doesn't fluctuate. Renewable energy is different, and it's good that this issue is mentioned in articles so that it's acknowledged as being a challenge. I don't think it's ambiguous in any way

ChuckMcM 9y ago
> ... you would never mention the load factor of a natural gas power plant because it's essentially a turnkey solution that doesn't fluctuate. As I understood the term the capacity factor is the percentage of time the plant is generating power. All plants have periods of maintenance and other "down times" which means they don't achieve 100% capacity. I would expect to use that number like this: Given a 30MW plant with a 50% capacity factor measured for the year, I would consider it to provide 30MW x 180 x 24 or 129,600 MWh of generating capacity. Two plants with a 50% capacity factor would give you coverage at their rated power all year only if they never overlapped in their down time. So if I was working the issue operationally I'd put in three plants to insure I had 100% coverage of 30MW all year long.
- cbcoutinho 9y ago
  Maintenance does incur planned downtime on a power plant, but those things can be planned for when there isn't much energy usage throughout the year. In colder climates that's usually in the spring/summer. If a plant goes out for two weeks every year for maintenance, that's not a big problem. A wind farm on the other hand has a much lower load factor (UK offshore is around 30% [0]), and that load capacity isn't planned at all. You might get 30% on average per year, but that daily capacity fluctuates throughout the year - that's what I mean about fluctuating capacity. [0] https://www.gov.uk/government/statistics/renewable-sources-of-energy-chapter-6-digest-of-united-kingdom-energy-statistics-dukes https://www.gov.uk/government/statistics/renewable-sources-o...

stephen_g 9y ago

It's badly worded, but most people should get the meaning in context of talking about capacity factor. "Every minute of every day" is just a common English expression to mean "all the time." The word "minute" in there isn't significant and doesn't factor in the calculation, it's just for emphasis. So really all the author means is "producing 30MW consistently for the whole time it's been in operation." Or if they did use minutes as a time slice in the capacity calculation, it would have to be "averaging 30MW during every minute of every day".

epistasis 9y ago

When there's a potential ambiguity and one meaning is sensical and the other nonsensical, that's not actually an ambiguity. Saying that this is ambiguous is paramount to making the assumption that the author does not know the difference, and then trying to twist the meanings to prove your point. That's unnecessarily tendentious.

bthornbury 9y ago
Precision of language is important.