Climate Change and Renewable Energy News and Discussion

enroger said:

The problem with green hydrogen is low energy efficiency, around 50% efficiency to electrolyze water, around 50% fuel cell efficiency to turn hydrogen into electricity, so overall about 25% energy efficiency.

Battery on the other hand has over 80% overall efficiency.

I have no doubt the future is going to be solar + storage, my bet is on battery. Especially as battery is getting cheaper and cheaper, cycle time keeps improving, now they are at 10k cycles, consider one charging cycle per day that is about 30 years of use. Only thing is to worry about scarcity of materials such as lithium, CATL's sodium battery is one to pay attention to.

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where do you get those numbers from?

the most recent electrolyzer from Mingyang has power usage of 3.8 kwh/NM3

H2 fuel density is 33.6 kwh/KG 1KG = 11.2 NM3, so fuel density is 3.0 kwh/NM3

so we are already at 79% in efficiency with alkaline electrolyzer. SOEC electrolyzer can get close to 100%

As for just use Hydrogen fuel purely for electricity, you can get 60+% efficiency with combine cycle gas turbine that does is able to handle both NG and H2. If you get one more optimized for H2, I wouldn't be surprised if you can get to 70% efficiency
In fact, the theoretical max I think is close to 75 to 80%.

battery storage is cheaper, but how are you going to transport from 1 region to another? What if you have a lot of excessive electricity that battery packs can't hold? How do you sell excessive energy to other countries that aren't connected to the same power grid as you?

tphuang said:

where do you get those numbers from?

the most recent electrolyzer from Mingyang has power usage of 3.8 kwh/NM3

H2 fuel density is 33.6 kwh/KG 1KG = 11.2 NM3, so fuel density is 3.0 kwh/NM3

so we are already at 79% in efficiency with alkaline electrolyzer. SOEC electrolyzer can get close to 100%

As for just use Hydrogen fuel purely for electricity, you can get 60+% efficiency with combine cycle gas turbine that does is able to handle both NG and H2. If you get one more optimized for H2, I wouldn't be surprised if you can get to 70% efficiency
In fact, the theoretical max I think is close to 75 to 80%.

battery storage is cheaper, but how are you going to transport from 1 region to another? What if you have a lot of excessive electricity that battery packs can't hold? How do you sell excessive energy to other countries that aren't connected to the same power grid as you?

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Right, turns out my numbers are decade too old, I'll defer to your numbers. If you have sources I'd appreciate.

Still even the most optimistic number leaves hydrogen behind battery and battery is still cheaper. As you said there're cases where hydrogen has advantages but I consider those to be niche use case, other than that battery can handle 90% of China's baseload much more economically.

Maybe hydrogen would make more sense for European countries for reason you mentioned, build solar farm in places like Egypt and ship the hydrogen to Germany for example. Another big use case for hydrogen would be transportation due to higher energy density.

Some times China's renewable industry blows my mind with what they develop
Here is Mingyang developing world's first Deep Ocean AI energy management platform called Deep Fusion X

Just combines floating turbine with floating solar, green hydrogen production, marine ranch, energy storage together. Using AI to figure out the best way to generate power, store energy and use for fishery.

A lot about weather forecasts and using Deep Fusion X to dispatch operation & maintenance as needed

Looks like Mingyang is build plant in Korea to produce wind turbines there with an investment of 2B RMB

MY also got 306MW onshore wind turbine order from Philippines.

enroger said:

Right, turns out my numbers are decade too old, I'll defer to your numbers. If you have sources I'd appreciate.

Still even the most optimistic number leaves hydrogen behind battery and battery is still cheaper. As you said there're cases where hydrogen has advantages but I consider those to be niche use case, other than that battery can handle 90% of China's baseload much more economically.

Maybe hydrogen would make more sense for European countries for reason you mentioned, build solar farm in places like Egypt and ship the hydrogen to Germany for example. Another big use case for hydrogen would be transportation due to higher energy density.

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take a look at some of these projects I'm posting here. How do you think ESS makes sense? A lot of the projects are economical because you don't have to connect them to the grid and just convert to green hydrogen or ammonia and then allow them to be shipped elsewhere.

China will have so much excessive electricity in certain regions. How are you going to transport electricity from Gobi deserts to coastal areas or for export? Sure, you can build high voltage lines, but those are expensive and take a long time to build and they loose power over distance.

You can now transport hydrogen in natural gas pipes. As technology improve, we will figure out even better ways to transport hydrogen or ammonia or methanol. There is boundless potential. There are a lot of industries and transportation that can't be converted to use electricity or batteries, that you have to use hydrogen or ammonia or methanol

tphuang said:

take a look at some of these projects I'm posting here. How do you think ESS makes sense? A lot of the projects are economical because you don't have to connect them to the grid and just convert to green hydrogen or ammonia and then allow them to be shipped elsewhere.

China will have so much excessive electricity in certain regions. How are you going to transport electricity from Gobi deserts to coastal areas or for export? Sure, you can build high voltage lines, but those are expensive and take a long time to build and they loose power over distance.

You can now transport hydrogen in natural gas pipes. As technology improve, we will figure out even better ways to transport hydrogen or ammonia or methanol. There is boundless potential. There are a lot of industries and transportation that can't be converted to use electricity or batteries, that you have to use hydrogen or ammonia or methanol

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High volt superconductor grid happens to be a specialty of China so I won't rule out that possibility. It comes down to cost, HV lines + battery VS hydrogen electrolyze + pipelines + generators.

The question I have is what is magnitude of water needed for terawatts of hydrogen production? Gobi is severely lacking in water so it needs to be piped in as well.

tphuang said:

take a look at some of these projects I'm posting here. How do you think ESS makes sense? A lot of the projects are economical because you don't have to connect them to the grid and just convert to green hydrogen or ammonia and then allow them to be shipped elsewhere.

China will have so much excessive electricity in certain regions. How are you going to transport electricity from Gobi deserts to coastal areas or for export? Sure, you can build high voltage lines, but those are expensive and take a long time to build and they loose power over distance.

You can now transport hydrogen in natural gas pipes. As technology improve, we will figure out even better ways to transport hydrogen or ammonia or methanol. There is boundless potential. There are a lot of industries and transportation that can't be converted to use electricity or batteries, that you have to use hydrogen or ammonia or methanol

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methanol isn't hard to transport. you transport it in a steel container at standard temperature and pressure. it is noncorrosive and liquid at STP.

the disadvantage of methanol is that you need CO or CO2 to form it from H2 and the only way to get industrial quantities of those is with fossil fuel.

ammonia is much harder to handle being corrosive, toxic and semicryogenic but Haber-Bosch is known.

enroger said:

High volt superconductor grid happens to be a specialty of China so I won't rule out that possibility. It comes down to cost, HV lines + battery VS hydrogen electrolyze + pipelines + generators.

The question I have is what is magnitude of water needed for terawatts of hydrogen production? Gobi is severely lacking in water so it needs to be piped in as well.

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I think each project will have to determine what's the most logical for them. As hydrogen in general becomes more efficient for production & transportation, the economy will get better. And just as importantly, the project operator also matters. A lot of the projects are funded by Sinopec & other companies that want to be large green hydrogen players. All things to consider. You need both green hydrogen and battery storage

As for water, it will have to be the same water source that people use. There are lakes around there

FairAndUnbiased said:

methanol isn't hard to transport. you transport it in a steel container at standard temperature and pressure. it is noncorrosive and liquid at STP.

the disadvantage of methanol is that you need CO or CO2 to form it from H2 and the only way to get industrial quantities of those is with fossil fuel.

ammonia is much harder to handle being corrosive, toxic and semicryogenic but Haber-Bosch is known.

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I think transporting both methanol & ammonia isn't difficult with the technology we have. I was more pointing to just the issue of transporting hydrogen in general. Do you find more efficient ways to transport it or do you have to convert it to ammonia or methanol. Keep in mind that there is a lot of industrial use for both, so many of the green H2 project are known as green ammonia or green methanol project right from the start.

Is there any news on China's advanced nuclear projects. Thorium molten salt reactor or the sodium cooled fast reactor?

tacoburger said:

Is there any news on China's advanced nuclear projects. Thorium molten salt reactor or the sodium cooled fast reactor?

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They will take some time. I wouldn't expect them to provide short term solution to energy security or de-carbonization goals


Anyhow, I still need to read this over, because it's really but Longi thinks we need to lower Green hydrogen cost to below 12.6 RMB/kg
now by personal calculation has worked out to be 10.64RMB/KG in another 5 to 7 years, so I think 12.6 is very easily doable. And I think cost & production level will come down a lot faster than people think. It has already done so in every other renewable field

Seawater extraction of uranium. Just a test platform for now. I hope that we eventually get figures as to how much uranium they can extract and the cost. If they don't have to be manned, there's no reason why you can't just have thousands of them dotting the coastline and have a crew come and harvest them once in a while. Or bundle them up with existing sea based infrastructure like oil rigs, offshore wind turbines, floating fish farms etc etc. Or extract from the concentrated brine that desalination produce before dumping it back onto the ocean. Or from coal ash that also contains trace amounts of uranium. It all depends on the cost of the mats that are used to absorb the uranium.


The floating platform. It's small but most off the action should be in the "mats" floating under the water, which could be several dozen meters long.