Yo this point “They are associated with extremists and unserious people. Renewables are still willfully tainted by their association with green movements, who are either clueless hippies or dangerous communists/totalitarian ideologies who want to take us back to the stone age.”, I’m sure you’re aware of it, but I would add that renewables are unfortunately stuck between what your describe and a good chunk of the new “ecologists” BANANAs (Build Absolutely Nothing Anywhere Near Anything) that favor nuclear (cf what you describe with the offshore wind turbines killing whales).
Not really. If it works, it works, no need to find these kind of excuses. But sadly, thet don't (as advertized); the main reason is density and intermitency, they just can't provide a steady electricty output without relying on back-up coal or gaz (see Germany). So their role will likely still be marginal, helping a bit in some regions
Germany demonstrates the exact opposite - renewables have replaced 40% of electricity previously provided by baseload plants (nuclear and lignite) and the system now requires less of the flexible kind of power (gas and hard coal), in MWh.
This is not about reality, this is about hy people are not interested in reality
In 2022, some 30 percent of gross electricity was generated using lignite and hard coal, considered the most polluting of energy sources. Natural gas contributed another 13 percent. This is huge and I don’t know how this is a victory for renewables unless I’m missing something
Just look at the starting point (when 30% was 60% or thereabouts, just 20 years ago). The fact that Germany chose to close nuclear plants before lignite plants can be criticised in that respect, but it only slowed down the trend to get rid of coal.
I think I agree with everything, but I find myself a bit puzzled by the following statement: "It requires more MWs of backup, but fewer MWh, and since with flexible plants it’s the MWh that are expensive, not the MW, it’s not even more expensive overall". Could you unpack it a bit? Thanks, I appreciate your insights.
MWh are actual energy, and MW is the throughput capacity: a MW delivers one MWh per hour
Instantaneous demand is expressed in MW, and volume of energy delivered in MW (maybe obvious, but better safe than sorry!)
Say you have a system that have demand varying from 20MW (Saturday night in the summer) to 50 MW (early evening in winter). You can manage that with 20 MW of baseload and 30+MW of flexible capacity than comes online when needed, or with a renewables system that's going to generate between a lot (potentially more than 50 MW when there's plenty of sun and wind, which might need to be curtailed) to very little (no wind at night)
When you have baseload, the difference between demand and that supply is 0-30 MW - but that demand profil is quite regular (the same shape every day, bigger in winter and smaller in sumer) - so the flexible capacity is needed to some extent every day, and up to 30 MW every now and then
With renewables, the supply profile is going to be a lot more irregular, and demand minus supply is going to vary essentially from 0 MW (when there's enough, or too much renewables) to 50 MW (when there isn't any). If you have enough capacity that there is a lot of renewables most of the time (not so impossible if you have a combination of solar, wind, hydro and storage), then the demand gap will be often close to zero, but will reach 50 MW every now and then.
So the peak of flexible capacity that you need is 50 MW instead of 30 MW with baseload. But the volume of electricity generated by the flexible capacity could be quite low (if the peaks of such demand gaps don't last long)
Flexible capacity is typically diesel or gas-fired plants - to exaggerate a bit, they don't cost a lot to build, and they cost money only to buy the fuel that will be burnt (and the carbon cost is similar - only when power is produced) - and they will sell these MWh at the price that the market will bear, which will be structurally high at that point as it's precisely when they are the only ones around to provide the supply, so they can set the price they want (moderated only by supply destruction, or regulated price caps)
The explanation makes total sense, but I think I didn’t explain myself properly. Maybe I inferred from your words some kind of hidden meaning that wasn’t there to begin with. My puzzlement didn’t stem from the MW vs MWh difference in itself. I guess the thing I couldn’t totally explain for myself was when you wrote “since with flexible plants it’s the MWh that are expensive, not the MW, it’s not even more expensive overall”.
The way I’m used to looking at things is that the marginal cost of renewable energy is or tends towards zero, so it’s the MW that is expensive to build, not the marginal MWh once the MW is built. This is kind of the opposite of how you described the issue.
It is of course expensive to build a flexible capacity that is large enough to cover the 0 to 50 MW requirement of your example.
So, with this aspect clarified, I think I now get the full picture of what you meant. We were just highlighting a different side of the same coin (at a different time of the coin flip).
Hi Jérôme,
Thank you for this informative article.
Yo this point “They are associated with extremists and unserious people. Renewables are still willfully tainted by their association with green movements, who are either clueless hippies or dangerous communists/totalitarian ideologies who want to take us back to the stone age.”, I’m sure you’re aware of it, but I would add that renewables are unfortunately stuck between what your describe and a good chunk of the new “ecologists” BANANAs (Build Absolutely Nothing Anywhere Near Anything) that favor nuclear (cf what you describe with the offshore wind turbines killing whales).
Thanks for the comment - indeed
Not really. If it works, it works, no need to find these kind of excuses. But sadly, thet don't (as advertized); the main reason is density and intermitency, they just can't provide a steady electricty output without relying on back-up coal or gaz (see Germany). So their role will likely still be marginal, helping a bit in some regions
Germany demonstrates the exact opposite - renewables have replaced 40% of electricity previously provided by baseload plants (nuclear and lignite) and the system now requires less of the flexible kind of power (gas and hard coal), in MWh.
This is not about reality, this is about hy people are not interested in reality
In 2022, some 30 percent of gross electricity was generated using lignite and hard coal, considered the most polluting of energy sources. Natural gas contributed another 13 percent. This is huge and I don’t know how this is a victory for renewables unless I’m missing something
Just look at the starting point (when 30% was 60% or thereabouts, just 20 years ago). The fact that Germany chose to close nuclear plants before lignite plants can be criticised in that respect, but it only slowed down the trend to get rid of coal.
I think I agree with everything, but I find myself a bit puzzled by the following statement: "It requires more MWs of backup, but fewer MWh, and since with flexible plants it’s the MWh that are expensive, not the MW, it’s not even more expensive overall". Could you unpack it a bit? Thanks, I appreciate your insights.
Sorry for the delayed reply, but yes let me try.
MWh are actual energy, and MW is the throughput capacity: a MW delivers one MWh per hour
Instantaneous demand is expressed in MW, and volume of energy delivered in MW (maybe obvious, but better safe than sorry!)
Say you have a system that have demand varying from 20MW (Saturday night in the summer) to 50 MW (early evening in winter). You can manage that with 20 MW of baseload and 30+MW of flexible capacity than comes online when needed, or with a renewables system that's going to generate between a lot (potentially more than 50 MW when there's plenty of sun and wind, which might need to be curtailed) to very little (no wind at night)
When you have baseload, the difference between demand and that supply is 0-30 MW - but that demand profil is quite regular (the same shape every day, bigger in winter and smaller in sumer) - so the flexible capacity is needed to some extent every day, and up to 30 MW every now and then
With renewables, the supply profile is going to be a lot more irregular, and demand minus supply is going to vary essentially from 0 MW (when there's enough, or too much renewables) to 50 MW (when there isn't any). If you have enough capacity that there is a lot of renewables most of the time (not so impossible if you have a combination of solar, wind, hydro and storage), then the demand gap will be often close to zero, but will reach 50 MW every now and then.
So the peak of flexible capacity that you need is 50 MW instead of 30 MW with baseload. But the volume of electricity generated by the flexible capacity could be quite low (if the peaks of such demand gaps don't last long)
Flexible capacity is typically diesel or gas-fired plants - to exaggerate a bit, they don't cost a lot to build, and they cost money only to buy the fuel that will be burnt (and the carbon cost is similar - only when power is produced) - and they will sell these MWh at the price that the market will bear, which will be structurally high at that point as it's precisely when they are the only ones around to provide the supply, so they can set the price they want (moderated only by supply destruction, or regulated price caps)
Thanks Jerome.
The explanation makes total sense, but I think I didn’t explain myself properly. Maybe I inferred from your words some kind of hidden meaning that wasn’t there to begin with. My puzzlement didn’t stem from the MW vs MWh difference in itself. I guess the thing I couldn’t totally explain for myself was when you wrote “since with flexible plants it’s the MWh that are expensive, not the MW, it’s not even more expensive overall”.
The way I’m used to looking at things is that the marginal cost of renewable energy is or tends towards zero, so it’s the MW that is expensive to build, not the marginal MWh once the MW is built. This is kind of the opposite of how you described the issue.
It is of course expensive to build a flexible capacity that is large enough to cover the 0 to 50 MW requirement of your example.
So, with this aspect clarified, I think I now get the full picture of what you meant. We were just highlighting a different side of the same coin (at a different time of the coin flip).
Thanks again.
The old distinction between the price and the cost...
I wrote about this 15 years ago: https://www.eurotrib.com/story/2009/5/1/174635/6513 I should re-post it, actually