Hannah Ritchie has a splendid substack/newsletter called By The Numbers, and last week she published a very interesting thought experiment.

If you took the land that's currently used for growing biofuels, and, while still keeping it devoted to energy production, used the space for solar panels instead, how would they compare?

As she says,

"The numbers were quite staggering. So staggering in fact, that I doubted myself. I ran the calculations many times, convinced I’d accidentally added a zero somewhere. I asked Pablo to also come up with an estimate, without telling him how I got to my numbers. As it turns out, we took slightly different approaches, but landed somewhere similar."

The world uses about 32 million hectares of land for biofuels, which is pretty amazing in itself.  That's about the size of Germany.  And the main use of biofuels is in transport, where they currently meet about 4% of global demands.

But when she ran the numbers, Ritchie discovered that using the land for solar instead would generate about enough electricity to meet the world's needs.  Note - that's not the world's transport needs, it's the world's entire electricity consumption! 

Now, she wasn't proposing that you actually could or should do this simple swap; there are obviously all sorts of extra factors like infrastructure, environment, battery storage, etc.  But it's a very effective illustration of just how inefficient biofuels are as a way of generating energy.  (And it's worth remembering that you can often grow crops or graze animals under solar panels as well.)

Their second idea was to suppose that all of the world's road transport was to be decarbonised; something that skeptics often say could never be done because of the energy requirements.  What would that take?

Well, it would take about one-quarter of the land currently used for biofuels. The space that, at present, provides 1% of global liquid fuel.