Getting to Carbon Zero

Good article from MIT putting some solid numbers on the environmental impact of ChatGPT and its relatives. This article is for a general audience; people interested in the technical details can find them at https://mit-genai.pubpub.org/pub/8ulgrckc/release/2

In Ghana, more than 90% of e-waste is recycled. In Europe, only about a third.

The Seattle Times asked the same questions I did, about grid resilience in the face of more powerful storms. It's a sign of the difficulty of the problem that potential solutions were consigned to a short paragraph at the end.

I don't have an answer. But dismissing concerns about grid resilience as scaremongering by climate skeptics (even though some of it definitely is) isn't the answer either.

Real rivers are messy.

From the every little bit helps department. While green spaces are a large scale answer to the urban heat island effect, dense buildings and parking lots are likely to be with us for a while. Retroreflectors -- the same materials used in highway signs -- can help by bouncing sunlight back into the sky, rather than to potentially absorbing surfaces.

The separator between the anode and cathode of a lithium-ion battery poses a major engineering challenge. Separator failure leads to an internal short circuit, with potentially catastrophic results. But simply increasing the separator thickness reduces battery capacity and can impede the flow of ions that the battery needs to function. A group of Korean researchers thinks they've made progress, with a thin SiO2 coating for a polymer separator.

On paper, thin film solar cells look like a promising alternative to CZ-grown bulk cells, with much less silicon waste. In practice, it turns out that the energy cost of thin film growth is also quite large and it's hard to match CZ-silicon's cell quality. The latest assault on this particular windmill comes from NexWafe, whose process involves epitaxial growth on a seed wafer. They're still in the process of scaling up, with facilities investments in both Germany and the US.

The reporting on this update says that plug-in hybrids had a tremendous spike in sales in February. Actually looking at the data, though, battery electric vehicles have about 80% of the plug-in vehicle market, with plug-in hybrids accounting for the rest. Plug-in vehicle sales -- battery and hybrid combined -- do appear to have surpassed hybrids without plugs. There's still a long way to go, though, with plug-ins of all kinds accounting for less than 10% of the US market in 2023.

Hydrogen is often mentioned as an ideal alternative fuel. Better energy density than batteries, and the combustion product is water. Unfortunately, most commercial hydrogen comes from natural gas because water splitting is a slow, energy-intensive reaction. A group at Dongguk University hopes to change that, with a more efficient catalyst based on molybdenum and ruthenium. Full technical details here.

I'm working on a longer piece about perovskite solar cells, but one of the key obstacles to their commercial success is the presence of lead. Researchers at Pusan National University think they've found a passivation solution to prevent lead leakage. Technical details here.

Scientists at the University of Western Australia have used the strontium/calcium ratio in sea sponge skeletons to track average global temperatures over the last couple of centuries. The results are ... not good. They think we've already passed the 2-degree threshold for serious climate impacts.

I wrote about the hybrid/gas/electric tradeoff a while back. The technology is changing, though. This analysis from the Washington Post suggests that electrics are a better deal for most commuters, especially those with ready access to charging.

The tocarbonzero.com domain is changing DNS providers, and also doing some improved forwarding behind the scenes. If something seems broken, message me here.