4 ms·

We have a lot of the transmission lines already although of course we need more. The major missing part is interconnects between countries, or regions of large

We have a lot of the transmission lines already although of course we need more. The major missing part is interconnects between countries, or regions of large countries like the US. Germany has an over supply of renewable energy on occasion but is unable to export the energy so it simply drives the price negative in Germany while prices are high elsewhere.

p_l 5y ago
Germany pays neighbours to stop their own wind farms to sell power from their own, because they can't ship the energy from wind-rich north southwards due to lack of necessary interconnects. It's not that simple. And the overbuilding necessary is usually more in range of 10x assuming favourable storage conditions (which aren't necessarily available).
- pfdietz 5y ago
  When I look at "Germany, 2011 weather data, 2030 cost assumptions" in https://model.energy/ https://model.energy/ I get an optimized solution (for synthetic baseload production) that has PV and wind curtailment at 4.6% and 12.3%, respectively. This solution includes batteries and hydrogen; generally when hydrogen is included curtailment is limited (because you can make hydrogen when the sources would have been curtailed, up to some point of sufficiently rare curtailment that the extra electrolysers don't make sense.)
  - p_l 5y ago
    This holds as long as hydrogen storage can be kept quite low (assuming no improvements in nuclear) i.e. you have plentiful underground caverns. Helps that the data they have on caverns is actually for germany. Mind you, the model misses things like "Bavaria is NIMBYing all necessary transit work" etc. which is why you have weird situation of Germany paying Netherlands to curtail wind farms while buying nuclear from France, because they have to route around NIMBYs. Only slightly related - I'd love if the cost comparisons in general discourse stopped avoiding the issue of intermittency (that's how you always get such low prices on wind and solar) and used costs that include capacity factor and dispatchability (which https://model.energy/ https://model.energy/ does). Having funding (and purchasing priority) decided on dispatchable green sources (whether hydro, wind/solar/battery/hydrogen mixes, or nuclear) would probably help a lot in stabilisation of grid and long term decarbonisation, even if it would reduce some frankly pathological incentives for renewable build out (pathological because of linked carbon-producing plant build out to stabilise the setup, while simultaneously using cheap peak production prices to push out stable setups)
    - pfdietz 5y ago
      That site may overestimate the cost of dealing with intermittency, since it doesn't include dispatchable demand. For example, if hydrogen is to be used in steelmaking or ammonia synthesis, that demand can also be added when renewables would otherwise be curtailed, and the hydrogen stored for later use. The site's model also does not include pumped hydro, or intermediate term thermal storage. All these extra options can only help reduce the cost of integrating renewables, and make renewables more competitive vs. nuclear.
      - ephbit 5y ago
        > ... dispatchable demand. For example, if hydrogen is to be used in steelmaking or ammonia synthesis, that demand can also be added when renewables would otherwise be curtailed, and the hydrogen stored for later use. Isn't the problem that electrolyzers mostly have to run 24/7 because they would otherwise not be profitable? Then all these processes that rely on hydrogen wouldn't actually belong to the dispatchable demand category. Dispatchable demand could be found in heat pumps (in combination with buffer tanks) for heating homes. (As long as there's sufficient grid capacity)
        pfdietz 5y ago
        When the idea was to turn relatively expensive electricity into hydrogen to replace gasoline, then it made sense to make the electrolyzers as efficient as practical, even if that made them more expensive. But using curtailed intermittent power is different: here, the electricity is cheap, and capital cost of the electrolyzer becomes more important than efficiency. Under these different design tradeoffs, one might use a different technology (alkaline electrolyzers without platinium group catalysts, say, rather than PEM cells with expensive Nafion membranes and platinum.) I have seen claims that alkaline electrolyzers are available for < $200/kW in China.
      - p_l 5y ago
        Pumped hydro has the problem of "we pretty much can't build more". As for curtailment-reducing tricks, that's a good argument but IMO not changing the base calculus much - the model is about replacing the base demand power sources, so that we can push the extra into peak. Bigger problem is that scaling down demand is problematic for dealing with underproduction, and also simply missing on power (Thus my preference for billing for dispatchable power generation, then extra peak could be funneled easier into bonus things like green hydrogen for non-storage etc.)
ch4s3 5y ago
This is both a political problem and an energy sovereignty issue. You could turn Libya into solar Russia, but would you want to do that? My other concern is that such a complex and interconnected system is likely to be fragile in unexpected ways. And none of this addresses the land area required for base load solar.
- ephbit 5y ago
  > ... concern is that such a complex and interconnected system is likely to be fragile in unexpected ways. I second that. The robustness of the current global energy supply system based largely upon solid, liquid and gaseous fuels stems from its flexibility and inherent buffering capability and the fact that lots of the connections/links are loose/weak/interchangeable. (Supplier of fuel xy can be chosen relatively spontaneously, completely unlike some cable which invariably connects two fixed geographic locations.) An intercontinental electrical grid is in comparison dramatically less flexible. I'd call it grossly negligent to even attempt to implement a world spanning grid exceeding lets say 15 % of total power transmission.

p_l 5y ago

Germany pays neighbours to stop their own wind farms to sell power from their own, because they can't ship the energy from wind-rich north southwards due to lack of necessary interconnects. It's not that simple. And the overbuilding necessary is usually more in range of 10x assuming favourable storage conditions (which aren't necessarily available).

pfdietz 5y ago
When I look at "Germany, 2011 weather data, 2030 cost assumptions" in https://model.energy/ https://model.energy/ I get an optimized solution (for synthetic baseload production) that has PV and wind curtailment at 4.6% and 12.3%, respectively. This solution includes batteries and hydrogen; generally when hydrogen is included curtailment is limited (because you can make hydrogen when the sources would have been curtailed, up to some point of sufficiently rare curtailment that the extra electrolysers don't make sense.)
- p_l 5y ago
  This holds as long as hydrogen storage can be kept quite low (assuming no improvements in nuclear) i.e. you have plentiful underground caverns. Helps that the data they have on caverns is actually for germany. Mind you, the model misses things like "Bavaria is NIMBYing all necessary transit work" etc. which is why you have weird situation of Germany paying Netherlands to curtail wind farms while buying nuclear from France, because they have to route around NIMBYs. Only slightly related - I'd love if the cost comparisons in general discourse stopped avoiding the issue of intermittency (that's how you always get such low prices on wind and solar) and used costs that include capacity factor and dispatchability (which https://model.energy/ https://model.energy/ does). Having funding (and purchasing priority) decided on dispatchable green sources (whether hydro, wind/solar/battery/hydrogen mixes, or nuclear) would probably help a lot in stabilisation of grid and long term decarbonisation, even if it would reduce some frankly pathological incentives for renewable build out (pathological because of linked carbon-producing plant build out to stabilise the setup, while simultaneously using cheap peak production prices to push out stable setups)
  - pfdietz 5y ago
    That site may overestimate the cost of dealing with intermittency, since it doesn't include dispatchable demand. For example, if hydrogen is to be used in steelmaking or ammonia synthesis, that demand can also be added when renewables would otherwise be curtailed, and the hydrogen stored for later use. The site's model also does not include pumped hydro, or intermediate term thermal storage. All these extra options can only help reduce the cost of integrating renewables, and make renewables more competitive vs. nuclear.
    - ephbit 5y ago
      > ... dispatchable demand. For example, if hydrogen is to be used in steelmaking or ammonia synthesis, that demand can also be added when renewables would otherwise be curtailed, and the hydrogen stored for later use. Isn't the problem that electrolyzers mostly have to run 24/7 because they would otherwise not be profitable? Then all these processes that rely on hydrogen wouldn't actually belong to the dispatchable demand category. Dispatchable demand could be found in heat pumps (in combination with buffer tanks) for heating homes. (As long as there's sufficient grid capacity)
      - pfdietz 5y ago
        When the idea was to turn relatively expensive electricity into hydrogen to replace gasoline, then it made sense to make the electrolyzers as efficient as practical, even if that made them more expensive. But using curtailed intermittent power is different: here, the electricity is cheap, and capital cost of the electrolyzer becomes more important than efficiency. Under these different design tradeoffs, one might use a different technology (alkaline electrolyzers without platinium group catalysts, say, rather than PEM cells with expensive Nafion membranes and platinum.) I have seen claims that alkaline electrolyzers are available for < $200/kW in China.
    - p_l 5y ago
      Pumped hydro has the problem of "we pretty much can't build more". As for curtailment-reducing tricks, that's a good argument but IMO not changing the base calculus much - the model is about replacing the base demand power sources, so that we can push the extra into peak. Bigger problem is that scaling down demand is problematic for dealing with underproduction, and also simply missing on power (Thus my preference for billing for dispatchable power generation, then extra peak could be funneled easier into bonus things like green hydrogen for non-storage etc.)

ch4s3 5y ago

This is both a political problem and an energy sovereignty issue. You could turn Libya into solar Russia, but would you want to do that? My other concern is that such a complex and interconnected system is likely to be fragile in unexpected ways. And none of this addresses the land area required for base load solar.

ephbit 5y ago
> ... concern is that such a complex and interconnected system is likely to be fragile in unexpected ways. I second that. The robustness of the current global energy supply system based largely upon solid, liquid and gaseous fuels stems from its flexibility and inherent buffering capability and the fact that lots of the connections/links are loose/weak/interchangeable. (Supplier of fuel xy can be chosen relatively spontaneously, completely unlike some cable which invariably connects two fixed geographic locations.) An intercontinental electrical grid is in comparison dramatically less flexible. I'd call it grossly negligent to even attempt to implement a world spanning grid exceeding lets say 15 % of total power transmission.