Thoughts for May 15, 2022
Hi all. This week’s topics include ammonia for energy storage, arsenic pollution, fusion torch, and abortion politics.
Ammonia and Energy Storage
One of the vexing problems with an electricity system with a high percentage of variable renewable sources is storage. Particularly in northern latitudes, the need for electricity goes up in the winter heating season, while production from solar power goes down. There are several possibilities for dealing with this problem, and one of them is long-duration storage (electricity storage that lasts for several days or longer). But so far there are not many promising options for doing this.
Ammonia, chemically NH3, is one option for doing so that, as far as I can tell, does not receive as much attention as it should. This paper gives a very good cost of storage, around 16-23 Eurocents/kWh. However, the roundtrip efficiency (35%) compares unfavorably with other long-duration storage options. This paper gives similar results: good cost but poor efficiency.
Hydrogen is a related option frequently suggested for storage. Hydrogen would be more efficient and conceptually simpler, as hydrogen production is a step in producing ammonia. But hydrogen is difficult and expensive to store, since the molecules are very light. Ammonia, by contrast, is easier to store, and we already have good experience with doing so.
In addition to transporting energy across time, as storage is meant to do, ammonia is straightforward to ship and serves as a good alternative to HVDC for transporting energy across space, as for example in the case of Australia’s new ammonia export venture.
Most ammonia is used today to produce fertilizers, without which it would be impossible to feed the world’s population. There are also several important industrial uses. Thus regardless of how ammonia’s role in the energy system shapes out, it is a critical molecule, and it constitutes about 1% of world energy production and 1% of world greenhouse gas emissions. And so there is a need to develop low-carbon ways of producing it, such as by electrolysis.
Arsenic in Soil
Arsenic is a heavy metal that, when it is present in large quantities in soil, gets into crops and causes severe health damage. Much of the world’s soils have arsenic levels exceeding standards from the World Health Organization. In Bangladesh, a country with a particularly severe arsenic problem due to geographical factors, 43,000 deaths per year are attributed to exposure.
It seems to me that the main cause of arsenic pollution is natural, as opposed to artificial. One artificial cause is (now banned in the US) arsenic-containing pesticides. This paper lists out some causes: natural sources include volcanic eruptions and sea sprays, and artificial sources include improper waste disposal, mining (particularly gold mining), chicken litter, cattle-dipping vats (an arsenic solution to kill ticks), coal burning, and pesticides.
Even if the cause of arsenic pollution is mostly natural, it is a serious problem that calls for a solution. One option is phytoremediation, which is the growing of certain plants or fungi to intake arsenic and other heavy metals.
My understanding of this subject is still very superficial. I’d like to understand things such as the sources of arsenic pollution in a more quantitative sense, what are some of the other solutions, and when would they be cost effective?
Fusion Torch
A fusion torch is one of the more exotic ideas for recycling. Introduced in a 1969 paper, the idea is to use the ultra-hot plasma of a fusion reactor to vaporize material, whereupon it can be separated by element and sorted. Here is a short summary.
Neutronic fusion (i.e. deuterium-tritium, the pathway that most research today is going to) might not work as a fusion torch, so aneutronic pathways, particular p-B11, are being explored.
I found this follow-up paper from 1971 amusing. They are concerned that the waste heat from all this fusion power, for recycling and other purposes, could warm the world. This is a distinct concern from contemporary climate change worries, which are that carbon dioxide and other greenhouse gases could trap heat. Waste heat from energy is a small part of the world’s energy flux, and I’d guess we would have to increase world primary energy by about a factor of 50 before waste heat becomes a major problem, though maybe at a lower level we’d run into localized problems. Energy and environmental work of the late 1960s/early 1970s is an odd combination of (now seemingly naive) enthusiasm for advancement in energy and (now seemingly irrational) anxiety over population.
It doesn’t seem like much is happening now, aside from this recent article suggesting the fusion torch as an option for processing material on the moon. It’s probably just as well.
Abortion Politics
In light of the recent leaked draft opinion overturning Roe v. Wade, abortion politics are very much at the forefront of attention. I’ll share a very non-comprehensive segment of things I find interesting and useful. Here it is worth reiterating the disclaimer that just because I find something interesting doesn’t mean that I endorse all its contents or even the main conclusion.
I would start with the philosopher Michael Huemer’s piece outlining some of the complexities. He reminds us that, if you think the question has a simple and obvious answer, you’re missing something. See also this piece of Michael Huemer illustrating some of the problematic legal aspects of Roe v. Wade.
Secular Pro-Life is an organization that I pay some attention to. Their shtick is exactly what the organization’s title suggests. See e.g. this piece from last year as a sampling of their work. It’s a shame that the pro-life movement has become so wrapped up with the Christian right, and in an apparent application of the Shirky Principle, they are generally hostile to people from outside their political bubble and appear to be more interested in fundraising and politicking than in actually making progress on the issue. If Roe v. Wade is in fact overturned, then the next frontier will be on state policy (the idea that Congress could implement a durable solution in the near future is fantasy), and so it is more important than ever to broaden their coalition outside of a narrow base.
In the interest of balance, here is Ari Armstrong outlining a (mostly) pro-choice case.
Another persistent criticism of the pro-life movement is that that phrases such as “sanctity of life” apply when one is talking about abortion but in few other contexts. An answer to that is “A Consistent Life Ethic”; see for instance this review of articles (you can see abstracts of the articles, but links to the individual articles are broken). I would consider the approach established in the preceding link a good start but incomplete.
I think that is enough for now.