There's been some chatter about Carbonscape, a newish company that has jumped on the biochar bandwagon. Their claim to fame is that they microwave woody materials until they char. FAQ.

What is Carbonscape’s particular contribution?

For millennia, the process of manufacturing charcoal has remained relatively unchanged. Since this time there have been many applications for charcoal but because it burns hotter and cleaner than wood, the greatest use has often been as a fuel.

Excitingly, Carbonscape has developed cutting edge techniques and world leading intellectual property around the technology and processes, revolutionising the conversion of wood waste and other biomass into charcoal. Our proprietary industrial microwave technology means that in spite of the energy used during production, the carbon captured draws down significantly more carbon dioxide from the atmosphere than it produces. Each industrial-scale unit converts 40–50% of wood debris into charcoal; one tonne of carbon dioxide can be fixed as charcoal per day. By converting carbon in organic material to charcoal, it can be then put into the ground where it does the most good.

All of the chatter about Carbonscape is either repetitive fluffing about biochar, or quotes from Tim Flannery who is on the Carbonscape Board as a Director. PR in other words.

But why wave wood? Making biochar is exothermic. After a small amount of external heat is applied the gases given off from pyrolysis are enough to keep the reaction going and do other useful work such as drive steam turbines to make electricity. And what becomes of those gases in the microwave system?

It seems like a convoluted way of making biochar that is less efficient than other methods.