Spotted on FCRN: a small amount of single-cell protein has been produced using electricity and carbon dioxide alone.
The researchers believe the protein produced in this way could be further developed for use as food and animal feed. All you need is energy (renewable obviously preferred) such as solar energy and CO2.
But it's very early days. It took them two weeks to produce just one gram!
I haven't explored the science and don't have a sense on the viable nature of scaling this, so let's not get too excited.