3 ms·
> batteries are better for storage of energy in most cases That's not true. There are two main storage cases: from day to night and from summer to winter. Beca
by credit_guy 3y ago
> batteries are better for storage of energy in most cases
That's not true. There are two main storage cases: from day to night and from summer to winter. Because there are 365 days and nights in a year and only one summer and one winter, a battery for seasonal storage needs to be 365 times cheaper than one for daily storage to break even after the same number of years. Of course, there are no batteries that are 365 times cheaper than lithium-ion batteries. Nothing comes close.
People are thinking that chemical energy storage could work for the case of seasonal storage. It doesn't quite work right now, but it's not off by 2 orders of magnitude, it's off by maybe a factor of 5. It is much more likely that we'll succeed in making green hydrogen production, transportation and storage economical than that we could make batteries cheaper by a factor of 100.
Separately, there is a fairly good chance that we'll be able to extract hydrogen from underground deposits (google "white hydrogen", e.g. [1]).
Third, hydrogen storage economics enjoys the square-cube law: larger pressurized tanks can hold a lot of hydrogen for not a much larger cost than smaller tanks. So hydrogen could make sense for applications where very large tanks are needed, and one such application is railways. A typical train oil car has a volume of about 130 m3. At 700 bar (typical storage tank pressure), one m3 of hydrogen weighs about 42 kg, so this is about 5.5 tons. Hydrogen has about 3 times the energy density of diesel, so that would be the equivalent of about 16 tons of diesel. Train have an efficiency of at least 400 ton-miles per gallon, which is more than 125 ton-miles per kg, or 2 million ton-miles for 16 tons. In other words, such a tanker car could be enough to propel a ten thousand ton freight train for 200 miles. It would be much easier to convert diesel locomotives to burn hydrogen than to electrify thousands of miles of railways, so there's a fairly good chance that rail could be hydrogen's killer app.
[1]https://www.theguardian.com/environment/2023/aug/12/prospectors-hit-the-gas-in-the-hunt-for-white-hydrogen https://www.theguardian.com/environment/2023/aug/12/prospect...
- tcfhgj 3y agoSummer to winter isn't a real storage case. If you need more energy in the winter, you build more wind power, not PV to store it an entire year. And episodes of little wind+sun have a duration of less than a month. And there are more storage use cases, e.g. short term grid stabilization (<1 second).
- rocqua 3y agoYou cannot reasonably dimension wind power to serve the winter heating needs of northern Europe. Once you get halfway there you're summer surpluses get so huge, inefficient seasonal storage becomes a much better solution.
- tcfhgj 3y agoInterestingly, others worry that the seasonal phenomenon of wind power is too large: https://blogs.scientificamerican.com/plugged-in/wind-patterns-and-electricity-generation-vary-across-the-seasons/ https://blogs.scientificamerican.com/plugged-in/wind-pattern... Perhaps southern Europe will counteract as well: less need in the winter and energy required for increased cooling with heat pumps in the summer
- rnk 3y agoCan you explain why existing batteries don't store energy well? I don't have to use energy to crack natural gas or water. I don't have to worry about the hydrogen leaking out and catching into an invisible fire. I don't have to carry around a tank with enormous pressure, because the hydrogen isn't very dense as an energy source. I could just say we'll solve all problems with green batteries. We can recycle batteries at > 95% of materials already. We have lifepo4 batteries that are stable, don't have cobalt and be charge up to 100% without destroying them. In reality I don't have to point to some unknown incredible improvements in the future, they work today. I see hydrogen as the oil industrial complex and diesel & ice industrial complexes wanting to maintain all their infrastructure that burns fuel for engines. It makes sense from their standpoint.
- rocqua 3y agoFor seasonal storage, because you cycle then so rarely, and demand between charging and discharging is so different, the economics favor low cost per kwh solutions, and care much less about efficiency.