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The crucial question that this article doesn't address is: replace coal with what? Germany has been closing its nuclear plants, which has largely negated the ga

The crucial question that this article doesn't address is: replace coal with what? Germany has been closing its nuclear plants, which has largely negated the gains they've made in wind and solar. Once renewable generation during peak production hours for solar and wind is saturated not much can be gained from further increases in solar and wind capacity. The only alternative for non-intermittent energy production (besides nuclear) is gas. And gas still emits carbon, and creates energy dependency on Russia.

Pfhreak 7y ago
Gas produces less CO2 and (I think?) is free from fly ash. But I'd suspect renewables, hydro, natural gas, and biogas would fill in for coal.
- lukasm 7y ago
  sulfur and other pollutants. coal is the dirtiest source of energy. Coal would die anyway (modulo anthracite). Gas, solar, wind and nuclear is gonna be cheaper in the future.
zepearl 7y ago
I agree that there is currently a lack of general discussion/activity related to energy storage during peak hours of renewables (or active production during <antonym of peak> hours of renewables). Maybe it's just not yet time for that... . I guess/hope that companies will jump into the energy storage sector (related to renewables) once there is demand and it becomes therefore financially interesting => some unorthodox ideas might come up in the future (which could be used as well for flat landscapes like the german one) (e.g. https://qz.com/1355672/stacking-concrete-blocks-is-a-surprisingly-efficient-way-to-store-energy/ https://qz.com/1355672/stacking-concrete-blocks-is-a-surpris... )
wffurr 7y ago
Storage. By building out storage, of which there is a plethora of possibilities, then peak production from renewables can be stored and dispatched later. Each unit of storage at that point can then displace some amount of baseline generation like coal or nuclear.
- izacus 7y ago
  What kind of storage though? Last I talked to some engineers at powerplants here in EU, they said that pretty much all places where you can build high efficiency storage (accumulation lakes / pumping powerplants) are already taken and in use. Now they state of the art is considering even horribly inefficient storage ( < 25% ) and that's going to require a lot of space and resources.
  - cygx 7y ago
    Possibly power-to-gas. Methane production at 75% efficiency has been demonstrated a while ago[1] and claims of potential round-trip efficencies of up to 80% have been made[2]. This is relevant because Germany's existing gas infrastructure can store several hundreds of TWh. [1] https://www.kit.edu/kit/english/pi_2018_009_power-to-gas-with-high-efficiency.php https://www.kit.edu/kit/english/pi_2018_009_power-to-gas-wit... [2] https://www.sciencedirect.com/science/article/pii/S0360544218320693 https://www.sciencedirect.com/science/article/pii/S036054421...
- manfredo 7y ago
  Storage at anywhere even remotely close the scale required to displace nuclear and fossil fuel generation remains a fantasy. To put this in perspective, California's largest energy storage facility has as much capacity as the Diablo canyon plant generates every five minutes.
thereallksnmnn 7y ago
There is a lot of research going on in this field. One solution I find rather interesting is to use the peak energy to generate gas using some bio-chemical reaction and then again burn it once you need to adapt to peaks [1]. You can also use the existing gas infrastructure to transport the gas from the wind-rich north to the industrial-rich south without having to build new electricity lines (which people are protesting against too). Imho, it's a purely political driven decission to prolong coal usage and I SHAME the corrupting lobby-culture for this, as it's not in the interest of the people and only in the interest of a few companies and their share holder's. [1] https://www.sciencedirect.com/science/article/pii/S0960148115301610 https://www.sciencedirect.com/science/article/pii/S096014811... Edit: Spelling
- manfredo 7y ago
  Even the most efficient combined cycle gas plants are in the 55-65% efficiency range. The Sabatier process is also at maximum 70% efficient, so end to end efficiency is ~40%. Furthermore, in order to convert co2 to ch4 you need a source of CO2. Extracting the small percentage of CO2 from the atmosphere is not feasible. You would have to somehow pump the exhaust of the gas plants into a containment vessel, but creating backpressure on a gas turbine interferes with the turbine. Germany, as well as California, exemplify the problem with intermittent energy sources. Solar and wind are cheap to displace 30-40% of fossil fuels, but going beyond that involves solving extremely difficult engineering challenges.
est31 7y ago
Gas emits less CO2 per KWh than lignite. lignite is one of the most CO2 heavy energy sources. Gas is an opportunity that we can use to save tons of CO2, right now. Also, we've been importing large amounts of energy, It's illusory to assume we're able to become energy self-sufficient with renewables. Russia is not the only natural gas exporter and in the fully-renewable future we'll probably import renewably generated natural gas.
solarkraft 7y ago
> Once renewable generation during peak production hours for solar and wind is saturated not much can be gained from further increases in solar and wind capacity. What is energy storage?

Pfhreak 7y ago

Gas produces less CO2 and (I think?) is free from fly ash. But I'd suspect renewables, hydro, natural gas, and biogas would fill in for coal.

lukasm 7y ago
sulfur and other pollutants. coal is the dirtiest source of energy. Coal would die anyway (modulo anthracite). Gas, solar, wind and nuclear is gonna be cheaper in the future.

zepearl 7y ago

I agree that there is currently a lack of general discussion/activity related to energy storage during peak hours of renewables (or active production during <antonym of peak> hours of renewables). Maybe it's just not yet time for that... . I guess/hope that companies will jump into the energy storage sector (related to renewables) once there is demand and it becomes therefore financially interesting => some unorthodox ideas might come up in the future (which could be used as well for flat landscapes like the german one) (e.g. https://qz.com/1355672/stacking-concrete-blocks-is-a-surprisingly-efficient-way-to-store-energy/ https://qz.com/1355672/stacking-concrete-blocks-is-a-surpris... )

wffurr 7y ago

Storage. By building out storage, of which there is a plethora of possibilities, then peak production from renewables can be stored and dispatched later. Each unit of storage at that point can then displace some amount of baseline generation like coal or nuclear.

izacus 7y ago
What kind of storage though? Last I talked to some engineers at powerplants here in EU, they said that pretty much all places where you can build high efficiency storage (accumulation lakes / pumping powerplants) are already taken and in use. Now they state of the art is considering even horribly inefficient storage ( < 25% ) and that's going to require a lot of space and resources.
- cygx 7y ago
  Possibly power-to-gas. Methane production at 75% efficiency has been demonstrated a while ago[1] and claims of potential round-trip efficencies of up to 80% have been made[2]. This is relevant because Germany's existing gas infrastructure can store several hundreds of TWh. [1] https://www.kit.edu/kit/english/pi_2018_009_power-to-gas-with-high-efficiency.php https://www.kit.edu/kit/english/pi_2018_009_power-to-gas-wit... [2] https://www.sciencedirect.com/science/article/pii/S0360544218320693 https://www.sciencedirect.com/science/article/pii/S036054421...
manfredo 7y ago
Storage at anywhere even remotely close the scale required to displace nuclear and fossil fuel generation remains a fantasy. To put this in perspective, California's largest energy storage facility has as much capacity as the Diablo canyon plant generates every five minutes.

thereallksnmnn 7y ago

There is a lot of research going on in this field. One solution I find rather interesting is to use the peak energy to generate gas using some bio-chemical reaction and then again burn it once you need to adapt to peaks [1]. You can also use the existing gas infrastructure to transport the gas from the wind-rich north to the industrial-rich south without having to build new electricity lines (which people are protesting against too). Imho, it's a purely political driven decission to prolong coal usage and I SHAME the corrupting lobby-culture for this, as it's not in the interest of the people and only in the interest of a few companies and their share holder's. [1] https://www.sciencedirect.com/science/article/pii/S0960148115301610 https://www.sciencedirect.com/science/article/pii/S096014811... Edit: Spelling

manfredo 7y ago
Even the most efficient combined cycle gas plants are in the 55-65% efficiency range. The Sabatier process is also at maximum 70% efficient, so end to end efficiency is ~40%. Furthermore, in order to convert co2 to ch4 you need a source of CO2. Extracting the small percentage of CO2 from the atmosphere is not feasible. You would have to somehow pump the exhaust of the gas plants into a containment vessel, but creating backpressure on a gas turbine interferes with the turbine. Germany, as well as California, exemplify the problem with intermittent energy sources. Solar and wind are cheap to displace 30-40% of fossil fuels, but going beyond that involves solving extremely difficult engineering challenges.

est31 7y ago

Gas emits less CO2 per KWh than lignite. lignite is one of the most CO2 heavy energy sources. Gas is an opportunity that we can use to save tons of CO2, right now. Also, we've been importing large amounts of energy, It's illusory to assume we're able to become energy self-sufficient with renewables. Russia is not the only natural gas exporter and in the fully-renewable future we'll probably import renewably generated natural gas.

solarkraft 7y ago

> Once renewable generation during peak production hours for solar and wind is saturated not much can be gained from further increases in solar and wind capacity. What is energy storage?