5 ms·

> that will make renewable energy storage a non-problem I recently played around with the data from Germany 2020. I scaled up the existing renewables (only the

> that will make renewable energy storage a non-problem I recently played around with the data from Germany 2020. I scaled up the existing renewables (only the ones that are scalable - wind and solar, hydro is pretty much maxed out) so that the yearly consumption can be served from 100% renewables. Then I added a battery to carry the overproduction over to the gaps. A 3 TWh battery would still lead to 50 days of empty battery and thus gaps in the power supply. This is electricity, not Transport and heating. And obviously my approach is simple, no sector coupling effects, no smart grid just scaling up want we have. 3 TWh is 30 million Model S batteries. Even with sodium ion batteries I think this is not really realistic. I always wondered why the are talking about hydrogen so much, despite the much higher losses you get in that process. Now I get it. I think batteries will be a good solution for single family homes / buildings with solar panel. But the grunt of the grid storage I think will be hydrogen. Especially because during winter, it can produce heat and electricity and the same gas turbines that are already common in German cities. Either way, it's a big, hard project, but doable if we really want to.

brianwawok 5y ago
Grid storage is different from powering EVs though. You don’t provide a week of grid backup via battery. You do stuff like pump 100 million gallons of water into a dam with a hydro plant ready. I think water is more efficient then hydrogen even.
- DanHulton 5y ago
  Sure, but it's very dependant on geography, if you want to do it at scale. We're definitely going to have to adopt a mixed approach, so I'd say it still makes sense to keep the research into hydrogen, batteries, all of it.
- maxerickson 5y ago
  That's 3 minutes of maximum generation at https://en.wikipedia.org/wiki/Ludington_Pumped_Storage_Power_Plant https://en.wikipedia.org/wiki/Ludington_Pumped_Storage_Power... I guess that plant doesn't have an extreme amount of head or a particularly large reservoir. It's about 7 minutes at https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Station https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Sta... , which has a lot more head. So you need a lot more pumped storage if you want to start talking about days of backup, and we already used quite a few of the best sites.
- turbinerneiter 5y ago
  Hydrogen is not very efficient, hydro is very efficient. But the energy density for hydro is lower than people think. m * g * h -> you either need lots of water or lots of height. Best is to have both. You only get that in the Alps and you need some special geoprgaphic features to make it work. Europe is also densely populated and the nature we have left, we want to preserve, so we can't flood all of it. Do the math, figure out how big of damn we would need to store 3TWh. My result: at 1000m pump height, you would need 3000 billion liters, which is cube of water with a length 1.5km. Double check this tough, I'm not sure if I did all the conversion correctly
  - japanuspus 5y ago
    I am not sure there is a universal value for "what people think" about pumped hydro energy density, but your numbers are quite far of: 3TWh at 1000m pump height would require 3e6Wh3600s/h/(1000m1000kg/m3*9.8m/s2) = 1.1e6m3, so a waist-high lake of one square kilometer would do. For what it is worth, in Europe, Switzerland is doing a lot of pumped hydro powered by surplus French nuclear power in the summer time. Norway has huge amounts of hydro and only pumps a little, but it doesn't matter much: The Scandinavian grid is so well connected, that hydro will ramp down when power is available elsewhere, in effect providing on-demand provider for the whole region.
KuzMenachem 5y ago
If you overprovision the electricity production you can get away with less battery capacity. It’s a tradeoff and the cost-optimal point is not going to be the one where the production is exactly equal to the demand.
- turbinerneiter 5y ago
  This was the most interesting finding: increasing production by 20% did more then increasing storage by 10x.
  - guerby 5y ago
    Yes that's why no one is going for 100% currently yearly production match with renewable, it will need to go higher in production :). Then you'll get times with overproduction with very low prices, this will prop up "power to storage for power later" (liquid, gaz, whatever) with buy low sell high usual market stuff. Note that France has currently 130 TWh of gaz storage capacity for about 473 TWh of yearly electricity consumption.
franckl 5y ago
Exactly, and we think ammonia is even better than hydrogen. It is easier to transport and to store (especially for places without underground salt caverns). See Https://www.airthium.com
jhgb 5y ago
> I recently played around with the data from Germany 2020. I scaled up the existing renewables (only the ones that are scalable - wind and solar, hydro is pretty much maxed out) so that the yearly consumption can be served from 100% renewables. Then I added a battery to carry the overproduction over to the gaps. A 3 TWh battery would still lead to 50 days of empty battery and thus gaps in the power supply. Did you use the approach outlined in https://doi.org/10.1016/j.euroecorev.2018.07.004 https://doi.org/10.1016/j.euroecorev.2018.07.004 ? Because "50 days of empty battery" is vastly different from the results in that work. 3 TWh is roughly 0.5% of German annual consumption and should bring you to at least a 90% renewable scenario, if not to 100%.
- turbinerneiter 5y ago
  90% is pretty close to the 50 days of empty battery. Keep in mind that on empty battery days, you still produce some energy as well. My approach was very very simple: if production is higher than consumption, store energy. Energy storage is limited, so when the stroage is full, energy is lost. If consumption is higher then production, take the difference from the battery. I have not considered any smart usage patterns or any advanced concepts at all. Also keep in mind that this ignores transport an heat. Pure electricity was what I looked at and that is somewhat around one third of the total energy used in Germany.
  - jhgb 5y ago
    > 90% is pretty close to the 50 days of empty battery. That's not quite how I understood "50 days of empty battery", but fair enough. This is not something that can't be solved, though. Even the 90% estimate is the worst case estimate, since there's actually a high likelihood of 3 TWh of storage being sufficient for 100% of renewables in any given German year. > My approach was very very simple: if production is higher than consumption, store energy. Energy storage is limited, so when the stroage is full, energy is lost. If consumption is higher then production, take the difference from the battery. That's Sinn's approach ("waste no energy and store everything, no matter the cost"), which yields significantly higher total costs (and storage capacities) than Zerrahn's approach which actually takes costs into consideration and leads to much smaller storage capacities on the basis of throwing energy away or using it opportunistically being actually cheaper than storing it for later grid use. > Also keep in mind that this ignores transport an heat. Transport and heat actually simplify things significantly for the grid since charging of EVs in Europe can be shifted around by as much as several days while heat will have been largely solved by the EU's 2010 and 2012 energy efficiency directives.
dzhiurgis 5y ago
My back of napkin calculation says transatlantic HVDC cable has lower LCOE than batteries, but question is capacity.
tgsovlerkhgsel 5y ago
> 3 TWh is 30 million Model S batteries Given that Germany has 60 million cars, that sounds not just realistic, but outright easy.

brianwawok 5y ago

Grid storage is different from powering EVs though. You don’t provide a week of grid backup via battery. You do stuff like pump 100 million gallons of water into a dam with a hydro plant ready. I think water is more efficient then hydrogen even.

DanHulton 5y ago
Sure, but it's very dependant on geography, if you want to do it at scale. We're definitely going to have to adopt a mixed approach, so I'd say it still makes sense to keep the research into hydrogen, batteries, all of it.
maxerickson 5y ago
That's 3 minutes of maximum generation at https://en.wikipedia.org/wiki/Ludington_Pumped_Storage_Power_Plant https://en.wikipedia.org/wiki/Ludington_Pumped_Storage_Power... I guess that plant doesn't have an extreme amount of head or a particularly large reservoir. It's about 7 minutes at https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Station https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Sta... , which has a lot more head. So you need a lot more pumped storage if you want to start talking about days of backup, and we already used quite a few of the best sites.
turbinerneiter 5y ago
Hydrogen is not very efficient, hydro is very efficient. But the energy density for hydro is lower than people think. m * g * h -> you either need lots of water or lots of height. Best is to have both. You only get that in the Alps and you need some special geoprgaphic features to make it work. Europe is also densely populated and the nature we have left, we want to preserve, so we can't flood all of it. Do the math, figure out how big of damn we would need to store 3TWh. My result: at 1000m pump height, you would need 3000 billion liters, which is cube of water with a length 1.5km. Double check this tough, I'm not sure if I did all the conversion correctly
- japanuspus 5y ago
  I am not sure there is a universal value for "what people think" about pumped hydro energy density, but your numbers are quite far of: 3TWh at 1000m pump height would require 3e6Wh3600s/h/(1000m1000kg/m3*9.8m/s2) = 1.1e6m3, so a waist-high lake of one square kilometer would do. For what it is worth, in Europe, Switzerland is doing a lot of pumped hydro powered by surplus French nuclear power in the summer time. Norway has huge amounts of hydro and only pumps a little, but it doesn't matter much: The Scandinavian grid is so well connected, that hydro will ramp down when power is available elsewhere, in effect providing on-demand provider for the whole region.

KuzMenachem 5y ago

If you overprovision the electricity production you can get away with less battery capacity. It’s a tradeoff and the cost-optimal point is not going to be the one where the production is exactly equal to the demand.

turbinerneiter 5y ago
This was the most interesting finding: increasing production by 20% did more then increasing storage by 10x.
- guerby 5y ago
  Yes that's why no one is going for 100% currently yearly production match with renewable, it will need to go higher in production :). Then you'll get times with overproduction with very low prices, this will prop up "power to storage for power later" (liquid, gaz, whatever) with buy low sell high usual market stuff. Note that France has currently 130 TWh of gaz storage capacity for about 473 TWh of yearly electricity consumption.

franckl 5y ago

Exactly, and we think ammonia is even better than hydrogen. It is easier to transport and to store (especially for places without underground salt caverns). See Https://www.airthium.com

jhgb 5y ago

> I recently played around with the data from Germany 2020. I scaled up the existing renewables (only the ones that are scalable - wind and solar, hydro is pretty much maxed out) so that the yearly consumption can be served from 100% renewables. Then I added a battery to carry the overproduction over to the gaps. A 3 TWh battery would still lead to 50 days of empty battery and thus gaps in the power supply. Did you use the approach outlined in https://doi.org/10.1016/j.euroecorev.2018.07.004 https://doi.org/10.1016/j.euroecorev.2018.07.004 ? Because "50 days of empty battery" is vastly different from the results in that work. 3 TWh is roughly 0.5% of German annual consumption and should bring you to at least a 90% renewable scenario, if not to 100%.

turbinerneiter 5y ago
90% is pretty close to the 50 days of empty battery. Keep in mind that on empty battery days, you still produce some energy as well. My approach was very very simple: if production is higher than consumption, store energy. Energy storage is limited, so when the stroage is full, energy is lost. If consumption is higher then production, take the difference from the battery. I have not considered any smart usage patterns or any advanced concepts at all. Also keep in mind that this ignores transport an heat. Pure electricity was what I looked at and that is somewhat around one third of the total energy used in Germany.
- jhgb 5y ago
  > 90% is pretty close to the 50 days of empty battery. That's not quite how I understood "50 days of empty battery", but fair enough. This is not something that can't be solved, though. Even the 90% estimate is the worst case estimate, since there's actually a high likelihood of 3 TWh of storage being sufficient for 100% of renewables in any given German year. > My approach was very very simple: if production is higher than consumption, store energy. Energy storage is limited, so when the stroage is full, energy is lost. If consumption is higher then production, take the difference from the battery. That's Sinn's approach ("waste no energy and store everything, no matter the cost"), which yields significantly higher total costs (and storage capacities) than Zerrahn's approach which actually takes costs into consideration and leads to much smaller storage capacities on the basis of throwing energy away or using it opportunistically being actually cheaper than storing it for later grid use. > Also keep in mind that this ignores transport an heat. Transport and heat actually simplify things significantly for the grid since charging of EVs in Europe can be shifted around by as much as several days while heat will have been largely solved by the EU's 2010 and 2012 energy efficiency directives.

dzhiurgis 5y ago

My back of napkin calculation says transatlantic HVDC cable has lower LCOE than batteries, but question is capacity.

tgsovlerkhgsel 5y ago

> 3 TWh is 30 million Model S batteries Given that Germany has 60 million cars, that sounds not just realistic, but outright easy.