@clive For those interested, the abstract is at https://pubs.rsc.org/en/content/articlelanding/2022/EE/D2EE00233G and the full paper is at https://www.rsc.org/suppdata/d2/ee/d2ee00233g/d2ee00233g1.pdf

It’s a lot more complicated (and frankly, more plausible) than the New Scientist article makes out.

The algae are growing both on the aluminium wool, and in the liquid.

The peak power involved is 4.2x10^-6W, and it’s only powering the CPU, nothing else. You’d literally need 10 million of these to make a normal LED light bulb turn on.