I recently have calculated the total cost of an energy system that is based on wind power as the primary power source and hydrogen as the energy storage mechanism. The total system costs are approximately similar to a system based only on new nuclear power plants built according to current regulations in the current market conditions. All of this is somewhat roughly estimated, as we don't know how much electrolyzers, hydrogen storage solutions, and hydrogen to electricity conversion in turbines or fuel cells costs in very large scales.
However, hydrogen needs to be stored somewhere. Its energy density by weight is extremely high, but energy density by volume is very low, even when compressed or liquefied. There are several solutions:
- Liquid hydrogen. Unfortunately, the energy efficiency of liquid hydrogen is low. Also, even with thermally isolated containers, the hydrogen needs to gradually leak away.
- Compressed hydrogen stored in pipelines. Unfortunately, hydrogen causes embrittlement of steel, possibly leading to hydrogen leaks.
- Storage in old mines, old depleted oil/gas fields, etc. However, hydrogen could theoretically leak.
All of these solutions have the possibility that hydrogen will leak away.
Therefore, my questions are:
- What are the environmental effects of hydrogen leaked to the atmosphere?
- What is the atmospheric lifetime of hydrogen?
- What is the global warming potential of hydrogen on timescales that matter (let's say 20 years or 100 years)?
- What is the mechanism of removal from the atmosphere? Oxidation to water, or similar to helium: escaping to space?
- Is the usage of hydrogen as an energy storage mechanism even justified based on the environmental effects, or are the effects so bad that it makes sense to continue burning of fossil fuels or reconsider nuclear energy?
