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Green hydrogen is a way to ship solar power elsewhere that doesn't have it, similar to a battery, but with the advantage of being able to be piped/pumped/liquif
by rswail 8mo ago
Green hydrogen is a way to ship solar power elsewhere that doesn't have it, similar to a battery, but with the advantage of being able to be piped/pumped/liquified etc.
- throwaway473825 8mo agoLiquid hydrogen loses 1% of its volume per day due to boil-off. Hydrogen is incredibly difficult to move without huge energy losses.
- pfdietz 8mo agoIt would be moved by pipeline as a compressed gas, not as LH2. The US already has > 1000 miles of H2 pipelines.
- closewith 8mo agoAll between co-located industrial generators and consumers. H2 pipelines are DOA due to the absurd compression costs.
- pfdietz 8mo agoA BTU of hydrogen requires more energy to compress to a given pressure than a BTU of natural gas, but hydrogen also has lower viscosity, so less recompression is needed. The point you raise does not rule out hydrogen pipelines.
- closewith 8mo agoIt does, definitively.
- pfdietz 8mo agoIf it does, then it also rules out long distance transmission of electrical power, as that is even more expensive. And the hydrogen advantage is even greater when one considers one can piggyback storage onto this system, as is done in natural gas pipelines. The electrical system would need additional batteries which are much more expensive per unit of storage capacity.
- closewith 8mo agoYou are simply wrong on this. HVDC losses total ~5% for 1,000km, including step up and step down losses. H2 will experience 20-30% over the same distance of natural gas line including compression and friction losses. DOA.
- pfdietz 8mo agoI said expensive. Total cost is the relevant metric, not efficiency. https://docs.nrel.gov/docs/fy22osti/81662.pdf https://docs.nrel.gov/docs/fy22osti/81662.pdf It's a common mistake to think efficiency dominates all other metrics. It's never just efficiency.
- closewith 8mo agoCapex for H2 pipelines is higher than new HVDC, and opex is 5-10x HVDC per MWh-km so you're just wrong on this. H2 makes sense for feedstocks but not energy distribution.
- pfdietz 8mo agoThe reference I gave you completely disagrees with your statement. So, present a link justifying it or I will just go with the link I have.
- closewith 8mo agoThe PDF you shared actually agrees with my point if you care you to read it. It models the cost for a specific HVDC implementation, but the HVDC line selected is more expensive when transporting just 3% of the energy of the pipeline. The same capex and opex can support 100x more Wh-km via HVDC, making HVDC at least an order of magnitude cheaper then the H2 pipeline. What's interesting to me is that this is completely uncontroversial and incontrovertible, so I wonder where your insistence otherwise is?
- adrian_b 8mo agoFor that purpose and for long-term storage of energy and for aircraft/spacecraft, synthetic hydrocarbons are much better. Making synthetic hydrocarbons was already done at large scale during WWII, but it was later abandoned due to the availability of very cheap extracted oil. So when oil was not available, the economy could still be based on synthetic hydrocarbons even with the inefficient methods of that time (it is true however that at that time they captured CO2 from burning coal or wood, not directly from the air, where it is diluted). Today one could develop much more efficient methods for synthesizing hydrocarbons from CO2 and water, but the level of investment for such technologies has been negligible in comparison with the money wasted for research in non-viable technologies, like using hydrogen instead of hydrocarbons, or with the money spent in things like AI datacenters.