6 ms·

The last I read into Germany's plan to be "100%" renewable, it was using other countries in Europe to provide the base load using their hydro and nuclear. Whic

The last I read into Germany's plan to be "100%" renewable, it was using other countries in Europe to provide the base load using their hydro and nuclear. Which is great so long as they have excess to provide Germany I suppose. There does not seem to be nearly enough construction of pumped storage or battery to cover the unevenness of German wind power. In fact, their prices have gone negative repeatedly in the past, which is not in fact a good thing. (OMG help, we'll pay anyone to take this power before the grid blows up!)

ncmncm 4y ago
It would be stupid to spend on storage before there is enough renewable generating capacity to charge it from. In the meantime they spend, sensibly, on renewable generating capacity. By the time there is enough, storage will be massively cheaper. In the meantime, charging storage from gas or coal and then drawing it down is the same as burning gas or coal for immediate use, just with losses.
- capitainenemo 4y ago
  The storage should be built in conjunction with the renewable generation to avoid those excess grid damaging events which is just wasteful. Similar issue to US where constructing generation is being subsidised but not constructing storage along with it.
  - ncmncm 4y ago
    There are no "grid damaging events".
    - capitainenemo 4y ago
      Correct, because they price it negatively to avoid that happening. It's still indicative of a problem.
- elihu 4y ago
  Batteries will probably be cheaper, but pumped hydro storage will probably cost about the same since it's a mature technology. I could see Norway or Switzerland being major players in pumped hydro storage, given their geography. Awhile back I did a bunch of math to try to figure out how much stored gravitational energy is in Lake Mead, and if I didn't make any major mistakes it came out to be about as much energy as the U.S. uses (as electrical energy) in 24 hours. The idea of moving that amount of water around on short time scales is hard to fathom.
  - ncmncm 4y ago
    The overwhelming majority of storage will not be batteries, unless a massively cheaper battery chemistry takes over. Lake Mead stores (well, stored) radically less energy than mountaintop reservoirs with thousands of feet of "head" can hold behind cheap earthen dikes. Look up "penstock".
    - elihu 4y ago
      I suppose I should have clarified that I meant "lake Mead if at capacity" which it isn't. Stored energy (in a fixed gravitational field) is the product of height and mass. Hoover dam has a "hydraulic height" of 576 feet according to a government website, though the average height of any given drop of water is less than that because the lake is deep (or it was, anyways). The thing about lake Mead is that the volume of water is absolutely huge. I don't think there are any mountaintop reservoirs anywhere close to it because though the altitude difference could be a lot more, it's hard to store large amounts of water on a mountaintop. If we estimate that the average height of water in Lake Mead is 400 feet and it holds 26 million acre feet, then a pumped hydro storage system with 4,000 feet of altitude difference would need to hold 2.6 million acre feet to be equivalent. I'm pretty sure there's nothing like that in the U.S. The Bath County Pumped Storage Station in Virginia has an upper reservoir of about 35.6 thousand acre feet and a vertical distance of 380 meters (1,246 feet).
      - ncmncm 4y ago
        There are dozens of such reservoirs in the Sierra Nevada range in California. None of them will take as much water as Lake Mead, but they don't need to. Sweden has lots of high mountains that may have shallow reservoirs built cheaply on top of. Reservoirs with earthen dikes are radically cheaper than the sort of dams needed for traditional hydro power, and may be placed almost anywhere, because they do not need or destroy a watershed. Lots of small ones, placed close to users, are better than one big one like Lake Mead.
froh 4y ago
> we'll pay anyone to take this power before the grid blows up that's not how that works. also: Dunkelflaute is 0.5% - 1.5% per year and only very rarely for longer than 24h. peaker power plants are turned off most of the time today and a combination of those and decentralized battery storage will easily buffer Dunkelflaute in Germany. https://en.m.wikipedia.org/wiki/Dunkelflaute https://en.m.wikipedia.org/wiki/Dunkelflaute
Isolus 4y ago
In fact, many believe that storage as hydrogen shows promise. There are many test plants for this right now in areas with a lot of wind and connection to the national gas grid. The idea is that the hydrogen can then be used in existing gas power plants.
- ncmncm 4y ago
  Hydrogen is one of many practical storage media. Many will be used, different ones favored in different places. Hydrogen is particularly suited for places with large, stable underground cavities.
- froh 4y ago
  hydrogen has a relatively poor efficiency compared to battery storage electricity to store and back, and it's an highly flammable, infamously explosive gas. but it has a high energy density and it can be transported relatively well. hydrogen will find it's niche.

ncmncm 4y ago

It would be stupid to spend on storage before there is enough renewable generating capacity to charge it from. In the meantime they spend, sensibly, on renewable generating capacity. By the time there is enough, storage will be massively cheaper. In the meantime, charging storage from gas or coal and then drawing it down is the same as burning gas or coal for immediate use, just with losses.

capitainenemo 4y ago
The storage should be built in conjunction with the renewable generation to avoid those excess grid damaging events which is just wasteful. Similar issue to US where constructing generation is being subsidised but not constructing storage along with it.
- ncmncm 4y ago
  There are no "grid damaging events".
  - capitainenemo 4y ago
    Correct, because they price it negatively to avoid that happening. It's still indicative of a problem.
elihu 4y ago
Batteries will probably be cheaper, but pumped hydro storage will probably cost about the same since it's a mature technology. I could see Norway or Switzerland being major players in pumped hydro storage, given their geography. Awhile back I did a bunch of math to try to figure out how much stored gravitational energy is in Lake Mead, and if I didn't make any major mistakes it came out to be about as much energy as the U.S. uses (as electrical energy) in 24 hours. The idea of moving that amount of water around on short time scales is hard to fathom.
- ncmncm 4y ago
  The overwhelming majority of storage will not be batteries, unless a massively cheaper battery chemistry takes over. Lake Mead stores (well, stored) radically less energy than mountaintop reservoirs with thousands of feet of "head" can hold behind cheap earthen dikes. Look up "penstock".
  - elihu 4y ago
    I suppose I should have clarified that I meant "lake Mead if at capacity" which it isn't. Stored energy (in a fixed gravitational field) is the product of height and mass. Hoover dam has a "hydraulic height" of 576 feet according to a government website, though the average height of any given drop of water is less than that because the lake is deep (or it was, anyways). The thing about lake Mead is that the volume of water is absolutely huge. I don't think there are any mountaintop reservoirs anywhere close to it because though the altitude difference could be a lot more, it's hard to store large amounts of water on a mountaintop. If we estimate that the average height of water in Lake Mead is 400 feet and it holds 26 million acre feet, then a pumped hydro storage system with 4,000 feet of altitude difference would need to hold 2.6 million acre feet to be equivalent. I'm pretty sure there's nothing like that in the U.S. The Bath County Pumped Storage Station in Virginia has an upper reservoir of about 35.6 thousand acre feet and a vertical distance of 380 meters (1,246 feet).
    - ncmncm 4y ago
      There are dozens of such reservoirs in the Sierra Nevada range in California. None of them will take as much water as Lake Mead, but they don't need to. Sweden has lots of high mountains that may have shallow reservoirs built cheaply on top of. Reservoirs with earthen dikes are radically cheaper than the sort of dams needed for traditional hydro power, and may be placed almost anywhere, because they do not need or destroy a watershed. Lots of small ones, placed close to users, are better than one big one like Lake Mead.

froh 4y ago

> we'll pay anyone to take this power before the grid blows up that's not how that works. also: Dunkelflaute is 0.5% - 1.5% per year and only very rarely for longer than 24h. peaker power plants are turned off most of the time today and a combination of those and decentralized battery storage will easily buffer Dunkelflaute in Germany. https://en.m.wikipedia.org/wiki/Dunkelflaute https://en.m.wikipedia.org/wiki/Dunkelflaute

Isolus 4y ago

In fact, many believe that storage as hydrogen shows promise. There are many test plants for this right now in areas with a lot of wind and connection to the national gas grid. The idea is that the hydrogen can then be used in existing gas power plants.

ncmncm 4y ago
Hydrogen is one of many practical storage media. Many will be used, different ones favored in different places. Hydrogen is particularly suited for places with large, stable underground cavities.
froh 4y ago
hydrogen has a relatively poor efficiency compared to battery storage electricity to store and back, and it's an highly flammable, infamously explosive gas. but it has a high energy density and it can be transported relatively well. hydrogen will find it's niche.